Watch out for fake 74LS logic ICs.  - Page 1
Forum section: electronics / projects

author: Fflint
author_rank: Frequent Contributor
timestamp: January 08, 2023, 09:01:10 am
content: I've heard a lot about fake opamps and other cheap ICs, but I never heard about fake 74LS logic ICs. I need specifically LS (or HCT) for compatibility with ancient devices and I recently bought some "cheap" SN74LS02N from a local ebay clone. When they arrived I noticed straight away the ti logo is fake, but I checked them in my Tl866II and it reported fine.Then once I tried to use them in a device with a 1mhz clock none out of 10 worked. I then got another two of the same chips, but from a reputable seller. Both of those work fine.Here is a photo of one chip from the reputable seller on top, and the fake one on the bottom.The seller returned my money and he wants the chips back tomorrow so there isn't much testing I can do, but I might just hook it up to a signal generator and an oscilloscope to seed what is it exactly about them that makes them fail.The supply chain situation for those chips must really be dire for people to resort to faking them. I now need 74LS133 which I can only get from China and I wonder if there is any chance of it being real...

author: james_s
author_rank: Super Contributor
timestamp: January 08, 2023, 09:13:57 am
content: It's prudent to just never buy stuff like that on ebay. It may be ok for tinkering around on a breadboard but you can't trust the specs and really, why not just buy from a reputable seller like Digikey? They are still fairly inexpensive and much more likely to be real genuine parts that meed the published specs.

author: Fflint
author_rank: Frequent Contributor
timestamp: January 08, 2023, 12:16:22 pm
content: Quote from: james_s on January 08, 2023, 09:13:57 amYou're right, but if only it was that easy (to always be able to buy from digikey or equivalents).What I do is hobby related and sometimes I do small runs of 5~10 units for sale too so this affects how I buy parts.Here(in my part of EU) we have 3 large distributors Digikey, Mouser and Farnell. Out of those 3 only Farnell has a local warehouse. Shipping is still expensive, but cheaper than the remaining two. Other than those 3 we also have lots of little family run shops that often have been in business for decades. They are usually quite reputable. Finally there are various auction and local ads sites (like ebay/Craigslist).The cost of shipping for those little shops is usually very cheap, double that for Farnell, double that again for Mouser, and double it for the third time for Digikey. Most of my order values are around what it costs to ship with digikey, but that is not the only issue with large distributors. These days it is very difficult to get all parts at one distributor. So imagine having to order with all 3.Also, the kind of older parts I often buy (74LS,STM32,Atmega etc) are sometimes found on local ad sites sold by individuals.So long story short, if you're making commercial projects and you have multi $k budget it is indeed prudent to only buy from big distributors. For small scale buyers... We sometimes have to take chances.Here is an updateabout those counterfeit chips as I've spent some time on a breadboard testing them and comparing with a genuine thing (bought in a local fairly reputable shop). Interestingly they can be made to work even at rather high speeds, but they have a much stronger tendency to self oscillate and the propagation delay is about 3 times the genuine thing.I used a breadboard as everyone knows those things are not ideal for signal integrity, but still there are lots of different behaviours between those two chips so let's list them. C is counterfeit, G is genuine1.C - Applying power to both chips with all inputs and outputs pulled down with 12k to ground (no decoupling cap) makes the chip oscillate immediately on two out of its 4 gates. The noise of this oscillations is present even on outputs of two gates that don't oscillate (at 1V).G - No oscillations2. 100nF ceramic decoupling cap added across power right next to chip.C - no differenceG - no difference3. Outputs of all gates have been switched from resistor pull downs to pull up(same 12k) to be in line with nand truth table.C - Self oscillations goneG - no difference4. Propagation delay measured.C - Approx 38nSG -Approx 12nS (still worse than datasheets value of 9)5. Square ttl signal was applied to one of each gate's inputs. Frequency was varied from 10kHz to 40Mhz.C - works fine until it starts drawing a lot more current at about 15MHz, 50mA PSU current limit cuts off power at around 23MHzG - Works fine all the way. Power consumption slightly rises from "0" to 3mA near 20MHz,Output amplitude drops slightly above 30MHz. I can't say if this is a chips fault or the breadboard wiring (likely the latter).6. Sine wave applied same frequency range (10k to 40MHz).C - Same effect as with square wave above 15MHz,below however the shape of the output signal looks "better" than the genuine thing? Strange.G - Fine all the way, but at mid frequencies of 1MHz the shape of the output looks a little strange. When it switches high it reaches well above threshold (about 4V),then slowly raises to 5V. The counterfeit chip went straight to 5V (when it worked).So here we have it. I suspect those are not even TI chips (on account of the propagation delay being so much higher), but some other make. Perhaps they are rejects from manufacturing that failed self oscillation/crosstalk tests. Do logic manufacturers do such tests? I have no idea.

author: wraper
author_rank: Unknown
timestamp: January 08, 2023, 12:31:17 pm
content: Quote from: Fflint on January 08, 2023, 12:16:22 pmYou have TME in Poland with <$4 delivery within your country.

author: wraper
author_rank: Unknown
timestamp: January 08, 2023, 12:32:30 pm
content: Quote from: Fflint on January 08, 2023, 09:01:10 amhttps://www.tme.eu/en/katalog/?search=74LS133&s_field=1000011&s_order=desc

author: wraper
author_rank: Unknown
timestamp: January 08, 2023, 12:46:09 pm
content: Also you have Maritex in Poland,https://www.maritex.com.pl/which can be more cost effective for common components and allows to buy cheap components at lower quantity. For example you can buy a single resistor for less than a centhttps://en.maritex.com.pl/passive_components/resistors/smt_resistors/chip_resistors_0603/resistors_0603_-_5/rmc0603-100k-h.html

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 08, 2023, 01:19:44 pm
content: Quote from: Fflint on January 08, 2023, 09:01:10 amGeez, if they don't even work at a milli Hz that must be real bad. I wonder how slow your Tl866II must be if it still is not able to flag this as an error.

author: Stray Electron
author_rank: Super Contributor
timestamp: January 08, 2023, 03:24:51 pm
content: FWIW I've never seen US made ICs that look like those. US made parts have a smooth slick finish but these have a pebble finish and they look like they may have been sand blasted to remove the original markings.That said, there are so many counterfeit electronic parts on the market today that I would not trust ANY part unless I bought it directly from a very reputable source such as Digikey.

author: CaptDon
author_rank: Super Contributor
timestamp: January 08, 2023, 03:36:45 pm
content: Yes doctor, I am sure we knew he meant Mhz but used mhz. And actually at 1mhz (Millihertz) they would probably transition through a linear range and self oscillate or do stupid things unless the 'one millihertz' clock still had a nice rise time.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 08, 2023, 04:25:19 pm
content: The supply current going up is a bit strange. Chance are the fake could be some slow (e.g. 74C02) version, maybe the 74L02 or 7400 - though I would not expect the high current consumption.For an 74LS02 there is really no need to resort to a dubious source like ebay. It may sometimes be OK for more excotic parts / old parts that are NOS, though with a risk.There are few more smaller resellers that have at least the more standard parts.

author: Bud
author_rank: Super Contributor
timestamp: January 08, 2023, 04:27:58 pm
content: When you consider all the troubles you had and time spent on testing, shipping charges from reputable distributors becomes a non-issue.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 08, 2023, 04:36:41 pm
content: Quote from: Stray Electron on January 08, 2023, 03:24:51 pmThe counterfeit part appears to be "blacktopped", which is where a black coating is applied over an original part, and new markings are applied.They counterfeit ceramic capacitors. Anything that gets into the electronic waste stream can be processed and appear in the counterfeit supply chain.

author: free_electron
author_rank: Super Contributor
timestamp: January 08, 2023, 06:30:11 pm
content: 22 arss 8 ... should have marked it arse ...

author: Fflint
author_rank: Frequent Contributor
timestamp: January 08, 2023, 10:40:36 pm
content: Quote from: wraper on January 08, 2023, 12:32:30 pmCool, thanks for this. I never knew :-)Quote from: wraper on January 08, 2023, 12:46:09 pmI saved this one too.

author: Fflint
author_rank: Frequent Contributor
timestamp: January 08, 2023, 11:30:36 pm
content: Quote from: Bud on January 08, 2023, 04:27:58 pmMy intention here is not to defend use of counterfeit parts, but if electronics is your hobby, not a paid job, and you know your way around measuring equipment as well as you already have one or two known good chips of the type you're buying I see no harm buying cheap parts and trying to find bargains. Especially when the site you're buying on has reasonable buyer protection. So as long as you're aware you might get burned there is no harm buying on all those sites. However, not everyone can tolerate issues that might crop up, and not everyone wants to spend half a day testing counterfeit chips out of curiosity, so I understand where you're coming from.Over all the years I've been buying electronic parts I've probably made no more than 5 orders to big suppliers. Everything else was bought through local ebay-clone-like sites, Aliexpress and ebay itself. This is the first time I actually got counterfeit parts and amongst my purchases before were such things as $120 a pop RF power transistors from Aliexpress, nice OCXOs, rf power resistors etc. (all expensive stuff I ever buy through such sites is from sellers with recent good feedback and prices that aren't "too good to be true").As for this experience I just would like to say it wasn't really much trouble for me(mainly because I had known good ICs from another source to check).It was quite interesting and educational. That's why I posted this thread. I was surprised such cheap ICs are being counterfeited in a fairly sophisticated way.For those interested in the details. Those chips were sold as "tested good" and I paid $3.4 (plus $2 local shipping) for 10 of them. When I contacted the seller with a complaint he didn't ask me to test them, he just wanted to know exactly what was wrong, once I explained he refunded me including shipping. He just asked I post them back in an economy letter (about $1.5). So one could say I'm loosing that buck and a half, but I agreed because technically he described them as "tested good" not "original TI" and they do test OK so I don't mind posting them back.For comparison's sake I already bought genuine TI SN74LS02N in a local physical store for $12.5 for 10. I'll definitely be ordering those 74ls133 from TME.

author: Stray Electron
author_rank: Super Contributor
timestamp: January 09, 2023, 12:25:19 am
content: I agree 100% with Bud on this. When I need to order parts, I usually need them for a repair or for a project that I'm working on and don't want to have waste time testing and troubleshooting the parts and possibly having to redo the repair. So I want GOOD parts to start with.If I want to test or play around with parts of unknown quality then I yank some off of one of the old circuit boards that I have laying around.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: January 09, 2023, 05:43:29 am
content: Either you consider your free time to be priceless or worthless, it seems.I also have no time for figuring out how to make counterfeits work for me. I don't want to buy counterfeits, EVER, because I don't want to support that "industry" in any way. All it does it make it harder to make nice things.

author: james_s
author_rank: Super Contributor
timestamp: January 09, 2023, 07:49:57 am
content: The only counterfeit parts I buy are the Maxim LED display drivers, the real ones are ridiculously expensive and the Chinese parts have always worked perfectly for my purposes.

author: Fflint
author_rank: Frequent Contributor
timestamp: January 09, 2023, 09:21:48 am
content: Quote from: Stray Electron on January 09, 2023, 12:25:19 amThose 5 times I ordered parts from large distributors were all for repairs. So I do agree with that.Quote from: Geoff-AU on January 09, 2023, 05:43:29 amFair enough. I suspect no one wants to "spend time making counterfeit parts work for them". At the same time there are plenty of people interested in reverse engineering them, making die photos etc.I have to admit I was tempted to decap those chips and to make some microscope photos of the dies, but I don't have a good way to decap them. Also based on the limited testing I think these are indeed 74ls02, but not meeting specs probably so nothing that exciting to see there.

author: bidrohini
author_rank: Regular Contributor
timestamp: January 09, 2023, 12:42:30 pm
content: I never really considered ebay a dependable source for components

author: magic
author_rank: Super Contributor
timestamp: January 09, 2023, 12:59:38 pm
content: I think the logo on the upper specimen looks dodgy too...

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: January 10, 2023, 07:31:32 am
content: Quote from: Fflint on January 09, 2023, 09:21:48 amI have a colleague who enjoys the challenge of making things work even though it's faulty. He understands that everything is junk, the seller knows that it's junk, they are getting a government subsidy for "exporting electronics" (even though it's faulty) and westerners are paying for the privilege of disposing of the junk by reciting the phrase "oh it was only a couple of bucks" while casting it into the bin. The people who complain about it being junk get offered a refund and that's just the cost of doing business. 100% is junk, 80% of people throw it away without a second thought because they have too much money to care, 20% complain so you give them refunds, and you're still making a healthy income stream from crowdsourcing your e-waste disposal on ebay.That whole thing gives me the shits though. I don't like my time being wasted by disingenuous people.

author: Fflint
author_rank: Frequent Contributor
timestamp: January 11, 2023, 01:21:20 pm
content: Quote from: magic on January 09, 2023, 12:59:38 pmIt does seem so right? But I know for a fact the shop I bought it at is legit and those chips spent 30 years sitting on a shelf there. Before they were bought from a big distributor. Also they test fine up to about ~40MHz and above that I suspect my breadboard and wiring was deteriorating the signals more than anything else. The measured propagation delay was slightly above the datasheet value at 12ns, not 9ns,but I think this is within acceptable tolerances.The store has been there for many decades. Interestingly when I told the woman working in the stora about the fake chips and how they are testing ok, but self resonate a lot more and have triple the propagation time she said back when they (the store) were buying 74xx chips directly from a local fab (CEMI used to be a Polish fab in distant past) there was an official route to buy them and an unofficial way at much lower prices, but then you got chips with no markings and usually with various faults. They(this store) were always getting official chips and that's one of the reasons they still exist 50 years later.I was mildly surprised counterfeit chip making wasn't a Chinese invention.I recently got some 74LS273 from another small local supplier that has good reputation and they look like this :To me they look a bit weird, but I never had chips made in Portugal before.Quote from: Geoff-AU on January 10, 2023, 07:31:32 amThere is a big difference in analysing those things to see how they done it and trying to make dodgy ics work in your device anyway. I tend to draw a line between the first and the second activity. I often buy from potentially dodgy sources, but I always get my money back if I get bad stuff. If everyone did that those guys would go out of business.The problem however, is that many people who buy such parts don't test them fully, meaning to use them for future projects. Even if they do have a logic IC tester, those testers(that I saw) rarely test parameters. They just test if the chip works.

author: tooki
author_rank: Super Contributor
timestamp: January 11, 2023, 07:09:56 pm
content: Quote from: Fflint on January 08, 2023, 12:16:22 pmDigikey has free shipping to Poland on orders above €50, customs/duty/VAT prepaid. So just keep a list of non-urgent stuff you need, and use items from the list to pad small orders to get to the free shipping threshold! (I mean, one can always get another Arduino or Nucleo board, or some flux, or some tool you’ve been wanting, or just restock standard components you’re running low on.)

author: Fflint
author_rank: Frequent Contributor
timestamp: January 12, 2023, 11:13:00 am
content: Quote from: tooki on January 11, 2023, 07:09:56 pmThanks, I didn't know.

author: tooki
author_rank: Super Contributor
timestamp: January 12, 2023, 12:16:42 pm
content: No problem! I didn’t check, but chances are that Mouser and Farnell are the same.

author: girishji
author_rank: Contributor
timestamp: January 15, 2023, 01:52:59 pm
content: As someone who lived in US for decades I can say it is cumbersome and expensive to get parts in Poland. In addition to expensive shipping there is VAT (daylight robbery). Some of the things I want are only on Mouser EU (ships from Chech) and some parts are only available to US customers. Digikey and Mouser are about the same. Farnell has less selection but cheaper shipping (VAT is inescapable). If you want something interesting it will most likely be missing on farnell. TME is still cheaper but even limited selection. Finally allegro for common cheap stuff. Difference in cost b/w US and EU becomes obvious when you order pcb's from jlcpcb.

author: magic
author_rank: Super Contributor
timestamp: January 15, 2023, 02:04:20 pm
content: LOL, what are you doing in this shithole?Quote from: girishji on January 15, 2023, 01:52:59 pmDoable, but you really need to know what you are doing or you end up brainf*cked like the OP.(For those not in the know, it's our local scambay/scamazon kind of site).

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2023, 03:31:28 pm
content: Quote from: girishji on January 15, 2023, 01:52:59 pmHow long has it been since you actually ordered from Digikey, Mouser, or Farnell to Poland?!?I didn't check Farnell, but Digikey and Mouser both ship DDP incoterms, which means VAT is covered by the seller. DDP means it arrives to you with all customs clearancedone.This wasn't always the case, but has been for a few years now.Quote from: girishji on January 15, 2023, 01:52:59 pmNope. While they have a sales office there, Mouser has exactly one warehouse for the entire world, and it's in Texas.Similarly, Digikey has exactly one warehouse for the entire world, and it's in Minnesota.Quote from: girishji on January 15, 2023, 01:52:59 pmNo, if it's DDP incoterms, VAT is already included.FYI, while Digikey shows the incoterms right on the screen where you select the country and currency, Mouser's website currently sorta hides it (probably by mistake; it used to be easier to find). But here's how to check without having to put stuff into the cart:Visithttps://www.mouser.pl/mvc/header/CurrencySelectionbut replace ".pl" with the TLD for your country.Now, in some cases (like Poland) it varies depending on shipping method, or even gives you the choice of incoterms. This is accessed by clicking the "More delivery options" link in the cart. The first screenshot shows what it looks like for an example €96 order (i.e. eligible for free shipping, since >€50) on mouser.pl.As you can clearly see, the default option, the free shipping, is DDP incoterms where you owenothingmore because it's already been collected.The current incoterms are also shown in the cart itself, see second screenshot.

author: Co6aka
author_rank: Unknown
timestamp: January 16, 2023, 04:07:31 am
content: Quote from: bidrohini on January 09, 2023, 12:42:30 pmWow, I must have missed all the changes... Used to be that eBay didn't sell components or any other goods because eBay was a platform for independent merchants to offer their wares on. Certain independent merchants were offering the fake stuff so many people preferred to buy because it was lower-priced than the genuine stuff other independent merchants were offering...but very few people were buying because it was higher-priced than the fake stuff. Gresham's Law prevailed and the independent merchants offering the higher-priced but genuine merchandise scrapped it and/or closed down their listings. Buyers prefer the lower-priced fake merchandise, and Brawndo's got what plants crave!

author: Fflint
author_rank: Frequent Contributor
timestamp: February 10, 2023, 12:47:27 pm
content: Quote from: magic on January 15, 2023, 02:04:20 pmShithole? Were you perhaps educated by the Soviet installed education system during the bygone era or shortly after? Many people at the time were thought to hate their own country at the time. Believe me, it can be cured. Best way is to live elsewhere for a while (not, just going for the summer, but actually living your life there for good number of years, buy a car and a house, change few jobs, use healthcare and gov services etc) then come back and tell me "it's a shithole" again.As for the site, I use it (and olx) all the time(as buyer and seller) and I never "got scammed" or "brain***ed". The seller did return my money and he even contacted me few days later offering me chips from another manufacturer for free. I declined, because I already got my chips elsewhere. In all likely hood he was scammed by his supplier.Quote from: tooki on January 15, 2023, 03:31:28 pmI never lived in US so I can't compare, but I did live in the UK for over 15 years. I wouldn't say getting parts in UK or Poland is any more or less cumbersome. Of course back then UK was in the EU(so shipping from and to EU was easy) and I lived a driving distance from the Farnell's sales counter in Leeds so that was nice, but their prices meant I usually shopped elsewhere anyway. Mostly on Ebay and via various small stores same as I do in PL now.As for VAT, I hate it too, but the problem is not who pays it, but that it is there. In UK it was 19% in PL it is 23% (ouch). However it is important to note in US prices are given excluding local sales taxes. Depending on the state it may mean nothing on top, or 12% on top. It is way lower than 23% of the VAT. I don't like it, but there is some consolation we do get more rights as buyers. For example any internet purchase in EU can be returned for no reason within 14 days, and warranty is compulsory for 2 years for individuals. I believe many stores offer the same or better in US, but not all.Quote from: tooki on January 15, 2023, 03:31:28 pmAre you sure of that? Last time I bought from Mouser EU they charged me about 60pln for shipping (about $13) and the order came in under a week. That's very cheap and quick shipping if they indeed ship from Texas. This seems to suggest they have an outfit in EU (maybe a shipping depot)?I can't say for digikey.Quote from: tooki on January 15, 2023, 03:31:28 pmAs for Farnell last time I ordered (2 years ago) I got an impression it came from another EU country too. I can't be sure though.Coming back to the subject of this post I recently bought a batch of Ti's 74LS133 from an Aliexpress seller for few $. They were significantly cheaper than all other options, but not stupid cheap (0.99$ free shipping - that woukd be just suspicious). They came in yesterday and as far as my testing can say they are legit...Here's a photo:This shows not all Aliexpress sellers are dodgy and applying some common sense (not going for cheapest, looking at reviews) can mean a good experience.

author: wraper
author_rank: Unknown
timestamp: February 10, 2023, 03:03:29 pm
content: Imho sanded, blacktopped, relabeled. Try rubbing marking with acetone or some other solvent.

author: wraper
author_rank: Unknown
timestamp: February 10, 2023, 03:10:33 pm
content: The have e4 marking which does not match with solder dipped terminals as it looks from the photo.Quote

author: ale500
author_rank: Frequent Contributor
timestamp: February 10, 2023, 03:35:03 pm
content: I got some 74HCT245 from aliexpress... they draw like 50 mA with all inputs at fixed values...

author: magic
author_rank: Super Contributor
timestamp: February 10, 2023, 05:15:09 pm
content: Quote from: Fflint on February 10, 2023, 12:47:27 pmIt was depressing to discover that we were the better side of the Iron Curtain after all, but those losers don't need to know about it.My comment wasn't directed to you, pls no bullyQuote from: Fflint on February 10, 2023, 12:47:27 pmYeah, you didn't get scammed, you just wasted your time and had to buy elsewhere.And if the part worked 99% right except for that 1% you spent a whole day debugging, then you'd see what brain***ed means.Pro tip: learn to tell apart old electronics shops selling their 1990s stock from Chinesium importers.Quote from: Fflint on February 10, 2023, 12:47:27 pmI would say they look fake, but can't be 100% sure because there have been several variants of TI logo over decades, maybe I haven't seen them all yet.They look laser etched so the markings won't come off with aceton, obviously. But wrong package option marking would be a serious indicator something is wrong.Check if the pins are fresh and stiff and have no traces of cleaning and re-tinning.FYI, every single chip onthis photowas fake. The only way to be sure is take them apart. Just because it looks similar to the original and passes simple tests doesn't mean it's the real thing and will meet all specs.Common types of fakes are recycled chips, similar but cheaper chips, similar recycled chips, or modern Chinese equivalents with fake markings applied right at the factory.

author: wraper
author_rank: Unknown
timestamp: February 10, 2023, 06:09:32 pm
content: Quote from: magic on February 10, 2023, 05:15:09 pmIt does not work on laser etching as such but often works on paint by which relabeled chips get coated on top. Though if chips get heated to high temperature then you no longer can remove the paint IME. Like you can easily remove paint before reflowing the board but not afterwards.

author: amyk
author_rank: Super Contributor
timestamp: February 11, 2023, 04:04:38 am
content: Quote from: Fflint on January 08, 2023, 12:16:22 pmThe delay looks more like an old CMOS logic family, and so does the "rail to rail" behaviour of the output that you saw with the sine wave.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 11, 2023, 11:31:27 am
content: Quote from: wraper on February 10, 2023, 03:03:29 pmOK, I have to take back what I said before... Not buying the cheapest and looking at ratings doesn't protect you from buying fake :-/Now, this is interesting to me. I'll definitely be decapping some of them to see the die.Quote from: magic on February 10, 2023, 05:15:09 pmOK, np.Quote from: magic on February 10, 2023, 05:15:09 pmI didn't spent a whole day debugging. There is a lot of text in this thread so details like this get lost. I had my doubts from the moment I saw them. The moment I plugged one into the device (a c64 cartridge) and it crashed every time it used I swapped the chip for known good one. The debugging took less than 5 min. However, as mentioned it is interesting to me that those chips passed the logic test so then I spent a day probing them further out of curiosity.Quite likely I'll spend even more time on the new chips I got that turned out to be fake... As I plan to decap them to find out what are they really. Do I have to do it? No, not really. Then there is an issue of leaving feedback on Aliexpress. I told the seller what I think about those chips and it is likely he'll refund me. I wonder if I'll be able to leave feedback then to warn others, or will the refund essentially cancel the transaction. We'll see.Quote from: magic on February 10, 2023, 05:15:09 pmYes, they are fake, and the marking does come off with acetone... Pity. Other than decapping I'm interested in checking if they match the parameters of the real chips. Do they suffer similar self resonance issues etc. O

author: magic
author_rank: Super Contributor
timestamp: February 11, 2023, 11:48:30 am
content: LOL, that's a lousy job. On better ones I could barely get rid of the black paint with nitric acid.This means they are probably recycled chips. You can often tell by the pins being weak and fragile and sometimes tinned unevenly. It helps to have some genuine brand new chip for comparison.They may be the exact type you ordered and most of them still functional, or something similar. Somebody suggested an equivalent CMOS gate, that wouldn't be out of question.Enjoy your Chinese roulette, you have been warned

author: wraper
author_rank: Unknown
timestamp: February 11, 2023, 05:12:55 pm
content: Quote from: magic on February 11, 2023, 11:48:30 amLeads are fragile when old leads were cut off and new leads welded on. But AFAIK it's more common with power transistors, power ICs and parts in metal can.

author: magic
author_rank: Super Contributor
timestamp: February 11, 2023, 05:21:03 pm
content: Those DIP leads have been factory bent, then bent some more for insertion, then abused during desoldering and cleaning, then bent back to factory angle, then shoved into foam by the retailer. They tend to become softer due to metal fatigue, sometimes to the point of breaking on the slightest excuse.

author: wraper
author_rank: Unknown
timestamp: February 11, 2023, 06:13:56 pm
content: Quote from: magic on February 11, 2023, 05:21:03 pmIf it's the case, leads will be noticeably ugly. If they look new but easily break, they are welded on.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 12, 2023, 12:11:25 am
content: If these are the actual chips, but desoldered, that woukd be fine by me, but I verh much doubt that. If they were original chips, why grind off markings?My logic tester tells me all chips have the right logic function, so they're either rebadged 74HC (much cheaper) - I'll test that by sweeping the inputs, voltage threshold is different in LS and HC, or maybe they don't meed requirements elsewhere(noise, frequency etc).I wonder when counterfeiting such cheap chips what method could be used to do it efficiently and still be profitable when selling them so cheap. People say they are pulled out of "trash" (as in old electronic devices). Just think how much labour it will take to remove them, sort them out(remember they do pass simple logic test) , grind them off, relabeled, sell them for pennies and still make profit? I can only guess, but I think it would be much more profitable to get some kind of Chinese made simple programmable logic, have them preground and blackened, when an order comes in, program the function, print the marking and away it goes.That's why I'm interested in how they do it and why I want to decap it. I'm kind of 50/50 expecting genuine ti reject, a different brand HC or some programmable logic. As far as I know no one decapped those fake 74ls Ali chips.Also, for people who want to roll the Chinese roulette wheel too, I would say the feedback process on Aliexpress is scammy as f***. For example I can't leave feedback if I opened a dispute. No option regardless of outcome. So if one has bad experience, one has to click "received item" which sends the money to the seller, then leave negative feedback, then open dispute. How many people are going to do that?I think I must have been very lucky to get so much good stuff from China through the years and only encountered this kind of fakery now. Maybe because I almost always bought used stuff? I very rarely buy stuff marked new.

author: amyk
author_rank: Super Contributor
timestamp: February 12, 2023, 06:42:34 am
content: With that propagation delay, it's not HC. Might be a CD die that's been rebonded, or 74C.

author: wraper
author_rank: Unknown
timestamp: February 12, 2023, 06:57:06 am
content: Quote from: Fflint on February 12, 2023, 12:11:25 amTo make them look brand new.QuoteMeasure current consumption, it's the most obvious difference between TTL and CMOS.

author: magic
author_rank: Super Contributor
timestamp: February 12, 2023, 10:04:45 am
content: AFAIK no bipolar logic can swing all the way up to VCC on the output, so I think that could be an easy test.Quote from: Fflint on February 12, 2023, 12:11:25 amYes, I think fake 74 logic is uncharted territory so far.I expect same outcome as with 555 timers, opamps or voltage references: the more expensive stuff is recycled scrap, the cheapest offerings are Chinese substitutes with false markings, for reasons you already suspect.Simple labor is cheap in China and they aren't using high technology for this. I recall a video about chip recycling posted somewhere on this forum. They were putting whole boards in a bowl of tin hanged over fire and pulling chips out with pliers, or something like that. Then the chips are sorted by type and either sold with original markings or "refreshed".Quote from: Fflint on February 12, 2023, 12:11:25 amMaybe they fucked it up recently, but I have a habit of leaving negative feedback only after I'm done recovering my money and I don't recall having problems with that on AE. And BTW, all feedback is deleted after 6 months anyway. The Chinese know best that consistency is not a thing that exists in ChinaMoney is not sent to the seller until two weeks after delivery confirmation. That's why you have two weeks to open dispute and AE guarantees your money back if they take your side.

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2023, 10:23:22 am
content: Quote from: Fflint on February 10, 2023, 12:47:27 pmThey use these nifty things called “airplanes” to quickly get things from one place to another.And because they do that tens of thousands of times each day, they get massive discounts with the shipping companies.So yes, I’m quite sure. We use Mouser and Digi-Key all the time at work (like, usually several orders a week), and those packages always come from USA. It says so on the boxes, but you can also easily check by using the tracking number of your shipment.Honestly, itisimpressive that they can get things sent so quickly, but that’s because they a) get your package out the door extremely quickly, and b) do a lot of pre-sorting themselves. Mouser and Digi-Key in essence have the first step of a UPS/FedEx depot within their facilities. So the shipping company isn’t picking up thousands of random packages, but rather bins that are already sorted by what airport they are headed to next. For example, Zurich is served by the UPS depot at the Cologne airport, which is a direct flight from the main UPS depot in Kentucky, USA. So Digi-Key will put any package to me in a bin to Cologne, and when UPS comes, they take that bin and know that everything in it goes directly onto the next plane to Cologne. And that’s how I can order it on Monday evening and have it Wednesday by lunch!

author: Fflint
author_rank: Frequent Contributor
timestamp: February 12, 2023, 05:58:22 pm
content: Now then. I mentioned I'll do decapping and I did. I have a nice optical microscope, but I have limited photo taking capability (basically I hold the mobile phone to the microscope).So here are the pictures of the die that is supposed to be SN74LS133N 82E24DKE4, also on the bottom of the chip plastic E9 is molded. It is supposed to be a 13 input Nand gate. It sure looks like one to me, but I have no idea about a brand. Do TI dies have a logo usually?Does anyone recognise it? Especially that B 2133 marking? Is there some site with 74LS die photos(or any 74 series) ? I couldn't find one.Quote from: magic on February 12, 2023, 10:04:45 amWell, that is surprising. Yesterday there was no option to leave feedback, today it appeared (a day after Aliexpress accepted my dispute). So I'll make sure to do it.Unfortunately, I also noticed I must have made a mistake and disregard my own rule... The guy has only one review on this item. I usually don't buy from sellers that have less than 7~8 recent ones. This was a low value item and I bought it before my previous "fake chip experience" so yeah, my mistake for falling for it.Quote from: tooki on February 12, 2023, 10:23:22 amOK, fair enough. I too think it is impressive.

author: wasedadoc
author_rank: Super Contributor
timestamp: February 12, 2023, 06:31:00 pm
content: Quote from: Fflint on February 12, 2023, 05:58:22 pmLooks like S133 with B underneath to me.

author: magic
author_rank: Super Contributor
timestamp: February 12, 2023, 08:04:07 pm
content: One of your images is mirroredAssuming this is a 133 type chip, pinout suggests that the first (darkfield) image is correct. So the marking reads:Code:S133Bwhich makes sense, I guess. Perhaps the S even stands for Schottky.The circuit is definitely bipolar and looks like a likely TTL NAND gate.Most TI dice have a logo: letters TI in rectangle. Seehere.Not sure who made this. Are base areas of transistors visible under brightfield? I can't really see them, but it could be just the quality of your image. If they are invisible, that strongly hints towards modern Chinese production. Which is perhaps good news in a way, it means somebody is still making these things.Quote from: Fflint on February 12, 2023, 05:58:22 pmWell, there ishttps://project5474.orgbut not a lot in there.

author: Bud
author_rank: Super Contributor
timestamp: February 12, 2023, 08:50:49 pm
content: Jeesus Murphy, so much trouble just because you boys do not want to buy from an industrial distributor?...

author: Fflint
author_rank: Frequent Contributor
timestamp: February 12, 2023, 11:42:51 pm
content: Quote from: edavid on February 12, 2023, 06:57:53 pmThat sure is interesting.Quote from: magic on February 12, 2023, 08:04:07 pmIndeed yes, the microscope mirrors it and I have to u mirror it in software. I took lots of photos (not knowing which one will come out OK). So I mistakenly added non-un-mirrored if it makes sense.Areas of transistors are clearly visible under reflective brightfield (if this is the correct term). I speak more about the setup below. It looks a lot better by eye.Here are two fragments of the same area zoomed in from full resolution with a little contrast and sharpness added before mirroring. You can just make out boxy outlines around transistors. Click on an image for a bigger version.This is generally a biology transmission microscope, with a led light from another microscope(much less magnifying) used for dark field. The first image in the previous post is dark field (light source positioned on top at an angle). The pinkish tinted image is an attempt at reflective brightfield by shining a led light into one eyepiece while looking through the other (it is an old Zeiss Letzlar microscope made in 1950s).Quote from: Bud on February 12, 2023, 08:50:49 pmAren't you curious how they do it and remain profitable? (previous post about them having a huge bowl of solder and paying peanuts for labour notwithstanding). I recently heard average labour rate in China now is double that of Mexico(no idea if true). And we have no(up to my knowledge) fake chips from Mexico!If this turns out to be the real deal from TI, then it is even more puzzling. It lacks the dice logo though so who knows. I would rather not sacrifice a real TI chip to find out(perhaps I will of there'll be no other way, but the 74ls to chips I have aren't 133s so I'm not sure how useful it's going to be. ) If anyone has a genuine TI made 74LS133 and wants to sacrifice it for decapping (and wants to post it to me in Poland) msg me for the address :-)Going that far (sanding relabelling, fixing leads) just to sell it as new when they could easily sell same 74ls133 as used to me for the same price (I would probably prefer old tested due to less chance of scam on used parts).I thought this reads 2133, but I agree it looks like S133B - bipolar so definitely not HC ergo LS, but made by whom? There is always a possibility it is a western made 74ls133 made by another manufacturer pulled from old hw and some person thinking TI chips sell better so they went to change the markings. Probably the simplest answer is the correct one.BTW, for anyone curious. You don't need nitric acid for decapping. Concentrated sulphuric acid will do, but it has to be hot (over 120C roughly). It has to be done in a fume hood or outside because it gives off noxious gasses. Also, don't heat the acid and plop the chip in. Put it in cold and slowly heat in a beaker on a hot plate. After 20min let water run through the black goop that results until it clears. Then throw it out onto a filter paper and look for your prize. Finally clean with isopropyl alcohol and a small brush. Physical cleaning is required as no amount of stirring will clean specs of black goop from the die. Overall a much more approachable process than dealing with hot nitric acid (potentially fuming). If I couldn't do it with sulphuric I would give up. I don't know why online sources prefer nitric.EditI was thinking about this letter B being there. I looked for anyone with 74ls133B chip, but only SGS Thomson made one (74ls133b1) and that b1 was for plastic package. There is no sense putting package code on the die... So perhaps it is a clue someone can decipher.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 13, 2023, 08:33:57 am
content: Quote from: edavid on February 13, 2023, 12:25:25 amI haven't yet. I will in a couple of days. Yes, I knew there was 74S133 (in TI' s "digital logic, pocket data book" for example), but I didn't connect the dots with this.In the meantime I looked for any datasheets from manufacturers that made this chip and I found TI, Motorola, ST (SGS Thomson I guess is the same thing, is it?) and that's it. Interestingly on TI pages if you go into products they don't even list 74ls133. There are lots of other 74ls products, but no 133. However, the S version is present in their book mentioned above.I wish someone wrote an article about the detailed history of simple logic before CMOS with die photos.Also I wonder if any an help with reverse engineering the schematic. Could someone comment on the below:These are clearly bipolar transistors. Right?And this I assume is a diode.But then what are these?And finally this. If anything? Maybe these are just connections.When I have more time I might send this die through an ultrasonic cleaner. I read online it helps. Also in future I might be interested in perhaps grinding the top surface down of this or similar chips slowly to reveal hidden layers. Anyone has an idea how thick those layers are on early pre-CMOS logic and how many there may be? I have a surface grinder precise enough to take off a sharpie mark from really flat steel without touching said steel(a micron or so) so with a diamond wheel it might work. However work holding this die and aligning it may be difficult.(encasing it in something would be obvious, but diamond wheels don't like epoxy..) Also I have no arbor for the diamond wheel yet (it's on a long list of upgrade projects). That's why I said "in future".

author: magic
author_rank: Super Contributor
timestamp: February 13, 2023, 10:49:42 am
content: Quote from: Fflint on February 12, 2023, 11:42:51 pmIt's not, though, because Noopy showed an old genuine TI 7400 with ball bonds.Quote from: Fflint on February 12, 2023, 11:42:51 pmNope, the bases aren't visible. Look at Noopy's 7400, the bases are red. You can clearly see one patch of base area with all the input emitters on it and a link to the pullup resistor, which is also made of a long and narrow "base". This is not visible on your chip and I don't think we have ever seen any classic bipolar chip from TI/ST/Motorola/Fairchild/Philips/etc which was like that. Smells like China to me.BTW, there is a schematic on Noopy's 7400 page. Hopefully you can figure out the difference between 2 and 13 inputs yourselfQuote from: Fflint on February 12, 2023, 11:42:51 pmYeah, I was wondering if it's like that. It's not too bad, but maybe not optimal yet because there is some unevenness. Are you placing the LED exactly in the exit pupil of the microscope?If not sure what this means, set it up for transmitted observation, pull out one ocular to confirm that exit pupil of the objective is filled 100% with light (open the aperture diaphragm as necessary), reinstall the ocular, hang a paper above it and look where you can see a sharp image of the objective's exit pupil. This image determines the optimal location and diameter of your LED. Fairly obvious if you think about it.When (ab)using biological objectives for reflected illumination, also make sure they have matte black backs, no shiny metal parts surrounding the pupil. Fairly easy to fix with matte electric tape if necessary.Quote from: Fflint on February 12, 2023, 11:42:51 pmBecause common 65% HNO₃ at 120°C produces same result in 5 minutes and without black goo. Bonding pads are completely etched away, though.Because FNA at 70°C or so (never done it) produces again the same result, but without bonding pad corrosion at all. The part remains functional.Online sources also say to clean with acetone if preservation of bonding pads is important. In my experience, H₂SO₄ damages them slightly by itself, even without water cleaning. I have seen claims that corrosion can be avoided with short bath in acid pre-heated to 200°C or more.Quote from: Fflint on February 13, 2023, 08:33:57 amYeah, these look like NPNs, unconnected of course. This silicon is likely capable of being several other ICs, depending on the final metal layer on top.Quote from: Fflint on February 13, 2023, 08:33:57 amNothing interesting in there. It's silicon with different dopants diffused into it (invisible without staining with nasty chemicals), some silicon oxide or nitride (transparent), some metal for connections, some more oxide or nitride. The oxide and metal layers can be cleanly removed chemically if desired.The oxide layer itself contains most useful information, because its thickness depends on the number of processing steps received by given area and this determine the color of reflected light by thin film interference.You may also want to take a look at this threadhttps://www.eevblog.com/forum/projects/decapping-and-chip-documentation-howto/

author: amyk
author_rank: Super Contributor
timestamp: February 14, 2023, 01:36:26 am
content: That's definitely bipolar, but here's another simple tip to distinguish them without decapping: both TTL and CMOS families will have diodes between Vcc and inputs, but they point in opposite directions; the input diodes on TTL point towards the inputs, while those of CMOS are protection diodes that point toward Vcc.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 14, 2023, 09:29:52 am
content: Quote from: magic on February 13, 2023, 10:49:42 amIt took me a while to figure out what is it you were talking about... For anyone else reading this. There is a user on this forum with a nick of Noopy, he has a personal blog/site where he has lots of cool die photos and stuff. Here is the page magic is referring to (I think)https://www.richis-lab.de/logic14.htmSo those ball bonds remove the only definitive proof of fakery we found so far (gold wires balled instead of aluminium wire bond)Quote from: magic on February 13, 2023, 10:49:42 amI wouldn't put a lot of importance at colors on my pink-violet tinted photos. Because of the way I have to take them there is a lot of Illumination light that bleeds back into the "receiving" eye piece. It takes a lot of fiddling to get them even as "good" as shown. I'll refer more to it lower(perhaps I can use the advice given). Also there are other color differences in certain areas between that noopy's photo and mine that suggest to me either his is some special way of photography with false color, or my colors are bad due to that over bleed of the Illumination light that comes off as pink-violet. Why is it pink-violet? I'm guessing it is a reflection from coatings on all the optical components. (those you can see with the same pink-violet tint when looking at certain lenses on binoculars etc - I always thought this is there to improve chromatic abberations, but I may be wrong).Quote from: magic on February 13, 2023, 10:49:42 amThanks, I didn't know getting rid of the reflection of the objective front surface is important. Also for how to find the optimal location of the led light.Unfortunately at the moment I have no way to precisely position the light other than holding one of my two led torches to the other eyepiece (touching it or slightly backing off). I can also remove the eyepiece and point the light down it's tube.My microscope's aperture diaphragm is not in the light path when using the episcopic (through eyepiece and the ocular) Illumination. The microscope is laborlux 3 (1954) with "Leitz brightfield condenser 600"under the table. The diaphragm is there to be used with a built in light source that is in the base. By saying it is setup for transmission microscopy (is this the right term?) I meant the light is on the bottom, then there is the condenser with diaphragm, then the table, objective revolver, then a head unit with two eyepieces. (a head unit with a tube for episcopic Illumination exists for this model, but it is rather expensive).To achieve Illumination through the objective, which seems the only way to resolve those tiny height differences in the oxide layer. Unfortunately the extraneous result is this pink-violet hue. If anyone has any idea how to get rid of it, please let me know. Perhaps I should try laser Illumination with a webcam, or try making polarizing filters.Quote from: magic on February 13, 2023, 10:49:42 amI saw no difference between acetone, or isopropyl alcohol, and even good old water when cleaning. The only benefit of acetone is that it dries faster perhaps.Quote from: magic on February 13, 2023, 10:49:42 amCould you explain what you mean by the "final metal layer on top"? I can clearly see aluminium metallic traces. The colors are true in the dark field photo I attached (the dark one). There you can clearly see the grey, slightly reflective sheen of aluminium. Perhaps including a zommed in bit will help.I used concentrated, 96% sulphuric acid, I didn't add any water to it. It shouldn't touch metals by much. Where gold balls are missing they were ripped during physical cleaning.Quote from: magic on February 13, 2023, 10:49:42 amThanks.Edit:Having spent some time looking at all the logic ICs photographed on the website linked above (Richie's Lab) I too am leaning towards thinking this is some old Chinese production IC. All TI chips I saw there have ti logo on the die. Other western manufacturers had more extraneous stuff on their dies. More numbers, letters, mask alignment features. Smaller feature sizes.This one seems a bit spartan in comparison. So I wouldn't be surprised if it was some Chinese make.

author: magic
author_rank: Super Contributor
timestamp: February 14, 2023, 11:07:42 am
content: Quote from: Fflint on February 14, 2023, 09:29:52 amDifferent chips made in different fabs end up with different color.It's determined by thickness of the transparent oxide layer (and angle of reflection, but that's fixed at 90° in this case).Same principle as oil spills on water appearing in random colors.Quote from: Fflint on February 14, 2023, 09:29:52 amAR coatings are there to reduce reflections off lens surfaces and increase transmission of the objective.Pretty much all optics have them, objectives purpose made for episcopic illumination even more so. They are not a problem.Metal traces on your image are reasonably neutral grey, so it isn't a serious problem for you either.Objectives may have slight color cast and "white" LEDs too. Camera white balance can fix it most of the time.Quote from: Fflint on February 14, 2023, 09:29:52 amTry again with an IC which isn't violetQuote from: Fflint on February 14, 2023, 09:29:52 amIdeally everything inside the scope should be black to absorb unintended stray light rather than reflect it towards the image.The edges of the objective are particularly at risk of being illuminated if you don't align your setup perfectly.This was not a problem in transmitted light applications so some old objectives have bare metal there.Quote from: Fflint on February 14, 2023, 09:29:52 amI suppose removing the ocular would only increase light pollution inside the scope. And dust ingress.My suggestion is to use the ocular to project an image of the LED precisely into the pupil of the objective, and only there.I think a round THT LED (3mm or 5mm) would be good fit, depending on ocular magnification. Make a mounting attachment for it out of cardboard/plastic/etc.You can pull the other ocular to inspect where the light went, make adjustments as necessary.Quote from: Fflint on February 14, 2023, 09:29:52 amOf course it isn't and the built-in illumination is useless for IC imaging.I only mentioned it as a way of locating the real image of the pupil through the ocular.Quote from: Fflint on February 14, 2023, 09:29:52 amExactly what I meant.This layer of aluminium traces is fabricated at the end of the process "on top" of the silicon to provide connections between circuit elements.Hence the same silicon may sometimes become a few different circuits, depending on metal configuration.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 14, 2023, 11:53:39 am
content: The "S" letter is very similar to the Signetics logo. They had a 74LS133 on their product line back in 1978.Page 204:http://w.bitsavers.org/components/signetics/_dataBooks/1978_Signetics_TTL_Data_Manual.pdf

author: Fflint
author_rank: Frequent Contributor
timestamp: February 14, 2023, 02:13:24 pm
content: Quote from: rsjsouza on February 14, 2023, 11:53:39 amThanks :-)I wish there was a site which collected die photos of same chip made by different manufacturers for simple logic. No doubt as those chips become more collectible over time people will be even more interested in identifying them.editthat's whathttps://project5474.orgis :-)Quote from: magic on February 14, 2023, 11:07:42 amYou can see how much extra color there is by looking at an area around the chip. It is a white double sided sticky tape. It should be white, but it appears dark blue/violet. Most likely this color is reflected from the chip.Quote from: magic on February 14, 2023, 11:07:42 amI see. I haven't got any white THT leds, just some smd ones. I might make something to hold a little pcb. Although now I'm exploring the possibility of adding a diy "vertical light" to my microscope. The binocular head is removable. It should be possible to fabricate an attachment that will move the head let's say 20mm higher and use the space to integrate a episcopic light from a diy 3d printable microscope project like PUMA (Maybe polarizing filters too).Quote from: magic on February 14, 2023, 11:07:42 amOK, I see.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 14, 2023, 10:37:38 pm
content: Here is a slightly better photo I took with light reflected off the face of the objective showing silicon features of a few transistors. Here you can clearly see green tint and even larger orange tint around the base below.I think this is the best it can get without extra vertical Illumination. I took that photo by using a powerfull led lamp in place of the original light, covered by a piece of thin paper, then using the original diaphragm and condenser. The ic die obscured direct light, but surrounding light reflected off the objective face illuminated it from the top. Unfortunately I have no dslr so I can't use a method used by Nooki for example. This one has a slight greenish tint unfortunately.Having seen all other die photos I still suspect Chinese production. I'll update this thread once I have measurements of current consumption and input voltage sweep.

author: magic
author_rank: Super Contributor
timestamp: February 14, 2023, 10:44:01 pm
content: Quote from: Fflint on February 14, 2023, 02:13:24 pmOkay, I see it. Not gonna lie, I sometimes get similar color cast if I use a crappy LED. I also have one ruskie objective which is somehow more blue than others. But it can be tweaked away with WB controls on the camera. I'm yet to see something so bad that even red or green turns blue.Quote from: Fflint on February 14, 2023, 02:13:24 pmSMD is not a problem, though many may prove too small. Maybe illuminate a small piece of ground glass with LEDs from behind.DIY attachment is an option too. In fact, I have bought an incomplete biological scope without any head at all and frankensteinedthis toweron top of it. This contains a DIY illuminator, appropriate extension tube and a camera (the Raynox "tube lens" got removed).Remarks:Smartphone mirror foil sucks, I'm looking for something better. There is noticeable loss of resolution when this mirror is inserted (while other lighting is used).I do use an extra lens to project an image of round LED into the objective, bouncing off the angled mirror.Some black paper in strategic places helps. I hope to post more about it in the future.Not sure how this compares to using the beam splitter of a bino head. I don't have a bino head.

author: magic
author_rank: Super Contributor
timestamp: February 14, 2023, 10:50:56 pm
content: Quote from: Fflint on February 14, 2023, 10:37:38 pmYes, that's nicer. You are right, base regions are distinct now. Maybe it can be a recycled Western chip after all.Quote from: Fflint on February 14, 2023, 10:37:38 pmThat sounds like about the same technique Noopy developed, but used with higher resolution optics. So what the heck.I tried it too with mixed results. Oftentimes there is not enough light passing around the die and still hitting the objective. I guess SLR lenses have an advantage here.Another option is angled transparent mirror between the specimen and the objective, but it causes quite bad blur even with 10x0.25. IIRC it was passable with 5x0.12.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 15, 2023, 08:13:12 am
content: Quote from: magic on February 14, 2023, 10:44:01 pmThe really bad colors resulted from using two cheap battery powered torches. One (the slightly more expensive one) even caused photos with visible vertical bands of light-dark (probably due to the low led drive frequency). There was an immediate improvement when I tried to use another led light that was much warmer, but heavy misting was present regardless of light position(through eyepiece). The original light that came with the microscope is incandescent so I wouldn't be surprised if the optics was optimised for this band somehow.Quote from: magic on February 14, 2023, 10:44:01 pmGood idea about the ground glass, I've been using paper, but I have a sander to I can sand/grind a piece of glass easily.Cool idea with your custom head/photo adapter in the thread you linked. One thing worth mentioning is that back in the 1900 when people were inventing microscopy they routinely used cover slips angled at 45 degres as beam splitters. If I can't get a tiny rod mirror, I might try that.The main problem with illuminating via one eyepiece of a bino head I have is misting (and glare, but that can be fixed a bit by positioning/intensity). I think it must be due to multiple prisms in the light path and lots of unwanted reflections. Also, some if the light (half?) is probably passing right from one eyepiece to the next.I have lots of broken Gu10 7W,600lm,4k K, LED lights (I collect them until I have 20 or so and then I repair them en-mass) so I pulled out the little aluminium board from one. I replaced the burned out led and I powered it with a bench psu at 60V (it was running at about 3W, not enough to heat a lot, but still lots of light. This is the light I used in the base. Until I fabricate the proper vertical light I might play with this a bit.Specifically, the chip's die is roughly a mm square, the white sticky tape holding it is maybe 0.3 mm bigger. So there is lots of light that goes around it that enters the objective. I have to try putting a piece of black backing behind it sized same as the objective lens so no strong direct light enters it. To get nice colors the light has to be very intense, but the slightest amount hitting the objective directly bounces around the scope on the inside and produces misting (despite Zeiss blacking it pretty well internally).Quote from: magic on February 14, 2023, 10:50:56 pmI read about Noopy's technique. If I had a dslr and some objectives I would do the same.When searching online I found this open source 3d printed microscope project called PUMA (Anyone looking for it just Google it). They have lots of cool attachments and the arrangements /parts they use are all great as a starting point for commercial modular scope mods. I think their vertical light is especially interesting. They use a beam splitter in the tube between objective/head. The light source is a single white led plus a condenser made with two cheap lenses. I think I might try a cover glass as a "poor man's beam splitter".

author: wraper
author_rank: Unknown
timestamp: February 15, 2023, 11:23:38 am
content: This thread proves yet once again that buy dodgy parts from China if you want to tinker with those parts instead of making things.

author: magic
author_rank: Super Contributor
timestamp: February 15, 2023, 12:26:34 pm
content: No joke, they truly are the cheapest shit out there for decapsulation and chip imaging R&DQuote from: Fflint on February 15, 2023, 08:13:12 amYeah, rolling shutter effect. For me it's 5V and 100Ω. These dice are very reflective, so it doesn't take a lot of light at all with illumination through the lens.Quote from: Fflint on February 15, 2023, 08:13:12 amStart with basics: a well defined uniform circle of light, projected by the ocular exactly into the glass of the objective.If there is still glare then yes, it's insufficient absorption of light in the beamsplitter, nothing that can be fixed without surgery, if possible at all. Taking the simple example of angled mirror foil (or cover glass as you suggest), some light fails to reflect down to the objective and passes through to the other side. You need to absorb that light well, because anything that returns to the mirror can be reflected upwards and mixed with the image. Similar effect likely occurs inside those bino heads somewhere. This is not a normal light path for them.My solution so far: use a piece of black paper, angled at 45° so that most of the reflection goes sideways. Maximize the distance from the mirror to the absorber to maximize light loss by scattering in random directions.Quote from: Fflint on February 15, 2023, 08:13:12 amThanks, will look it up. Their illuminator seems similar to mine, but I found a way to do it with one lens. But I don't have a variable aperture diaphragm - it's fixed by LED diameter. Not a big deal, because diaphragm setting must match exit pupil diameter rather than NA of the objective, and that varies little with magnification.editInserting anything below the head increases primary image distance, and if your scope is not infinity corrected, spherical aberration correction in the objectives will be thrown out of whack. It shouldn't be a problem with 10x0.25, but not sure about more powerful optics like 40x0.65 or oil if you fancy going that far. It is my understanding that original attachments of that sorts contained extra optics which compensate for this. Magnification increases too. Again, not an issue in infinity scopes.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 15, 2023, 01:11:04 pm
content: Quote from: magic on February 15, 2023, 12:26:34 pmThat's not good :-( I was hoping to use it primarily with my 40x objective (and perhaps with the 100x oil one). For other objectives like 10 (and even 3) I could figure out alternative arrangements as the distance between the sample and the objective is many mm.I doubt my laborlux 3 is infinity corrected, because it was made in 1954. Also the head has 1.5x written on it and it contains a lens in addition to prisms and eyepieces. This is useful info. If I choose to go down this route I have to weight the potential increase in image quality due to better lighting with deterioration due to new spherical abberations. I imagine I can limit them by attempting to insert as small amount of extra height as possible. With a rod mirror I could probably manage to do it all in 5mm. (total length is 150mm). A rod mirror is just a very thin rod with its end cut at 45deg and polished. It will obscure some of the light, but not a lot.Quote from: wraper on February 15, 2023, 11:23:38 amI can't say I disagree...BTW, Is anyone aware of any software (preferably open source / free, but knowing about commercial options would be nice too) that can do automated image stitching and focus stackingat the same time? The "at the same time" is the key requirement. There is plenty of tools that can do one or another with limited alignment capabilities. However, yesterday I took a number (about 50) photos of that die with 3~4 of each area intending to focus-stack and stitch them, but there are few issues. Just focus stacking photos covering same area results in photos that are slightly out of focus in corners, those corners often overlap other areas that are on very good focus. If there was some software that can do both a panorama stich and a focus stack at the same time, it could make a nice very high resolution picture from it. There is a lot of detail on those photos, but they are all generally half in half out of focus due to the tilt of the chip. Of course it is possible to generate a focus map for each picture. Make it into an alpha channel and then stitch it manually all in gimp, but it sounds like hours of work...Two examples of those photos :

author: magic
author_rank: Super Contributor
timestamp: February 15, 2023, 01:27:21 pm
content: My goal is to avoid stacking by having everything aligned. Flat die, flat slide glass, flat stage.I'm almost there, but the stage is misaligned somewhat. I plan to insert corrective shims under it, but I want to do it together with other mods/repairs and I'm still gathering parts and procrastinating around it a littleQuote from: Fflint on February 15, 2023, 01:11:04 pmThere is a simple test: raise the ocular in the head tube by the same amount, refocus, see if it made a difference.150mm sounds like a 160mm mechanical tube length system, so finite. 160 should be printed on the objectives.As far as I'm concerned, 10x0.25 is good enough for most bipolar tech.Not sure how a rod mirror could work as a splitter? The image forming light needs to pass undisturbed...

author: hanakp
author_rank: Regular Contributor
timestamp: February 15, 2023, 06:54:55 pm
content: @Fflint: I have Tesla MH74ALS02 from 1980s, PM me if you're interested.https://www.teslakatalog.cz/MH74ALS02.htmlMany such Tesla-made ICs are also available on Ebay, I doubt anyone would go though the trouble of faking those. I alone own literally thousands of MH74xxx TTLs, including industrial-temp MH84xxx and even some military-spec MH54xxx. But they're so cheap now it's not worth the hassle putting them up for sale.Oh, and in case the non-european crowd wonders, Tesla was a czechoslovak state-run electronics company:https://en.wikipedia.org/wiki/Tesla_(Czechoslovak_company)

author: magic
author_rank: Super Contributor
timestamp: February 15, 2023, 08:33:05 pm
content: PUMA microscope epi illuminator and related parts:https://youtu.be/cAEB10K8PqIhttps://youtu.be/uB48D5KueU8I watched most of both videos and agree with most everything there. Similar design to mine.Interesting ideas for light traps.Polarization is something I haven't considered but looks potentially interesting.I wouldn't bother reproducing their Nelsonian illumination optics, Köhler is the way to go.I have an idea how to do almost perfect Köhler setup with one lens and two stops (variable or fixed) for aperture and field control.Preliminary prototype shows that the field stop does provide some degree of improvement.The illumination path is as follows:beam splitter ← converging lens with a few cm focal length ← field stop in the image conjugate plane ← aperture stop in the pupil conjugate plane ← uniform diffuse light right behind the aperture stopThe conjugate planes are guaranteed to come in this order as they are on different sides of the focal plane of the converging lens.Two final elements are currently replaced with an LED of appropriate diameter.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 16, 2023, 10:06:38 am
content: Quote from: magic on February 15, 2023, 01:27:21 pmI see. With a 10x objective my current chip seems flat enough, but when I go to 40x (let alone 100) it is then I discovered it is not flat at all. I would be interested in finding out if there are any ways anyone might have to flatten it. The plastic is completely gone. The die lies on its clean back on a microscope slide already. Also I found I can get better image quality by adding a drop of microscope oil on the due and a cover slip on top, but of course the cover slip is not flat either so this adds to the alignment problem.Quote from: magic on February 15, 2023, 01:27:21 pmI'll try the head raising test.Unfortunately for taking photos I'm using a mobile phone, also due to the way I'm illuminating the chip if there is light passing around it it will make the mobile phone photo unusable. So the die ideally should fill the entire field of view. That is "almost there" with 10x, so I have to use 40x. Also there is so much more detail visible with 40x...As for the rod mirror, it can't function as a splitter, it is a simple mirror, but it is positioned far from any focus point. My understanding is obscuring, let's say 5% of the light path with it will not cause the image to be much worse.Quote from: magic on February 15, 2023, 08:33:05 pmThis went over my head a bit, nevermind. Regarding polarisation I ordered two cheap photography polarisation filters to do an experiment with my "through eyepiece" Illumination.

author: magic
author_rank: Super Contributor
timestamp: February 16, 2023, 11:00:18 am
content: Quote from: Fflint on February 16, 2023, 10:06:38 amCover slip is necessary for biological objectives more than ~0.4NA and it's a PITA because any junk on the die, bonding balls etc, causes it to tilt.As for the rest, I think my slide glasses are flat enough because I can rotate them 180° and nothing changes. This hints that my problem is in the stage itself.Common 10x0.25 achromats deliver plenty of detail already but it may take high mag oculars to see. I find 20x0.4 to be acceptable without cover glass too, but they are rarer.I use direct projection onto a USB camera image sensor. I see a small crop of the FOV (don't need to care about plan) and pretty much the maximum resolution of the optics.Quote from: Fflint on February 16, 2023, 10:06:38 amIt's fairly simple stuff. You could probably understand more just by looking up the definitions of all that jargon.Unfortunately, I haven't had much time to play with it (and still don't) so this project is stuck for now. I hope to build something more permanent than a paper prototype and show how to reproduce it.I think bino-epi is a good starting point, your images aren't too bad. If polarizing filters could improve contrast further, that's a win.

author: Fflint
author_rank: Frequent Contributor
timestamp: February 17, 2023, 11:39:01 am
content: I played with the polarisation filters a bit. To be honest I expected a bigger difference, but there is some difference. It seems height differencec in the die are slightly enhanced and it becomes apparent flat surfaces aren't ideał (a diffraction like pattern - rainbow of colors) can be seen in few places. Mind that the best photos I took were with the die submerged in microscope oil (these are not the photos with the entire die visible, I'm talking about individual transistors etc). While today I kept the die dry, because I had only few minutes of time to spend on it. This is the same reason why I haven't taken any photos. It is possible to hold a light, and two filters in one's hand while observing, but adding a mobile phone to this is impossible (not enough hands..). So I would need to fabricate some adapters/holders.I have more interesting chips coming (no - not from China... These will be Polish CEMI made logic and hopefully Czech Tesla chips). So I'll fabricate those adapters, but it'll take some time and it will go into it's own thread (or into an already existing thread we have here).I've been thinking what is the best photography device accessible to me (no DSLR) and I decided in favor of medium resolution and very good dynamic range. I have a Cctv Camera board that uses a Sony Imx335 sensor. It is a 5M pix sensor with very good dynamic range. I plan to make an adapter for it to mount it on the eyepiece. Pehaps with no lens, using direct imaging like magic. Maybe 10x objective will be good enough for me too then. A led light woukd be mounted to another eyepiece.I might be able to remove "misting" in software. By taking a picture with no specimen and then subtracting it from the picture of interest.I have lots of ideas, I wish I had more time in a day to try them all :-)

author: philpem
author_rank: Frequent Contributor
timestamp: February 22, 2023, 01:11:36 am
content: Quote from: Fflint on February 12, 2023, 11:42:51 pmThat "S" looks a lot like the Signetics logo. I can't find any evidence of them producing the 74LS133, but it could be a 74S133:https://en.wikipedia.org/wiki/Signeticshttps://www.datasheetarchive.com/pdf/download.php?id=0720bef359401ea49557d1f057a04258271e46&type=M&term=74S133The giveaway would seem to be the power consumption. The 74S133 pulls between 5 and 10mA -http://www.bitsavers.org/components/signetics/_dataBooks/1978_Signetics_TTL_Data_Manual.pdf(page 206)Whereas the Motorola 74LS133 pulls between 0.5 and 1.1mA:https://pdf1.alldatasheet.com/datasheet-pdf/view/5654/MOTOROLA/74LS133.html

author: rsjsouza
author_rank: Super Contributor
timestamp: February 22, 2023, 11:37:20 am
content: Quote from: philpem on February 22, 2023, 01:11:36 amCheck reply #57 above from me.