Don't buy from Rochester - Page 1
Forum section: electronics / general

author: ksilabs
author_rank: Regular Contributor
timestamp: August 24, 2025, 02:47:19 am
content: Some other issues aside (not having what they claim to have in stock etc.) they sold me a bunch of LT1007ACP opamps. I didn't check those until today and was extremely surprised to look at the markings -- those had a [poorly printed] TI logo. So, it is Linear Technology/Analog Devices opamps presumably made by TI.It would've been interesting to see what's inside but don't have time to bother with that. Going to garbage and not going to buy ANYTHING from Rochester, never ever. And it took several iterations to send me something that was supposed to be LT1007ACP.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 24, 2025, 03:11:42 am
content: You mean this part:https://www.rocelec.com/part/01t4w00000PPMD1AAP-LT1007ACPClearly listed as a TI part with a TI data sheet?I guess TI made an equivalent to the LT1007 in the 90s with the ACP suffix (which isn't used by linear tech). Never heard of it before but it's not surprising.Why would you order that part from Rochester? Their whole thing is keeping stock of obsolete, out of production parts and charging you a significant premium for that service. You only buy from them when you have no other option. The only reason to buy that part is if you designed a product 30 years with the TI LT1007ACP and you for some reason need to buy exactly that part rather than the Linear part it's a clone of. Normal people just buy the still in production LT1007 from regular distributors.You shouldn't have any concern about what's inside, it will be a genuine TI part.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 24, 2025, 04:00:35 am
content: Quote from: ejeffrey on August 24, 2025, 03:11:42 amHm... It is interesting... If you search the entire TI site you will find just 3 mentions of LT1007 and they are "What the TI equivalent of LT1007?".OK, maybe they are not fakes after all, who knows... However, marking is very poor, the manufacturing date (first line) says "2316VST" and there are 3 molded lines on the back:11...TAIWANU6Still looks suspicious...As of why would somebody buy those from Rochester -- it was a "top-off'. They claimed to have something like 25 or so LM369BH in stock that I purchased ALL but that was shy of their minimum $250 order so I topped it off with something  useful to make it over $250. Sure enough they did NOT have those LM369BH so they cancelled them and just sent me some other parts instead of those LT1007ACP. Those were sent on the second attempt after returning what they sent originally.

author: amyk
author_rank: Super Contributor
timestamp: August 24, 2025, 04:38:09 am
content: Pictures please.

author: aeg
author_rank: Regular Contributor
timestamp: August 24, 2025, 05:41:42 am
content: What did they send you instead of LT1007ACP the first time?

author: ksilabs
author_rank: Regular Contributor
timestamp: August 24, 2025, 07:33:54 am
content: Quote from: amyk on August 24, 2025, 04:38:09 amWill send tomorrow, it is past midnight here now...

author: ksilabs
author_rank: Regular Contributor
timestamp: August 24, 2025, 07:50:25 am
content: Quote from: aeg on August 24, 2025, 05:41:42 amLT1037CP (without 'A'), also from TI. Also unknown to TI.BTW, what's interesting, those "TI" LT1007 and LT1037 are being found on various non-US distributors' sites, including DigiKey, LCSC, and million others "having in stock" every part you can come up with, even if it never existed at all.The reputable sites clearly tell it is from Rochester. The hot air sellers don't.

author: brucehoult
author_rank: Super Contributor
timestamp: August 24, 2025, 07:58:21 am
content: Quote from: ksilabs on August 24, 2025, 07:50:25 amWhat's the problem here? If Digikey can get it from Rochester and you're buying other things from them then they can consolidate the orders and save you time and shipping. They probably have a shipment from Rochester every day.

author: ejeffrey
author_rank: Super Contributor
timestamp: August 24, 2025, 01:59:11 pm
content: Quote from: ksilabs on August 24, 2025, 07:50:25 amIf you are still questioning whether the LT1007ACP exists (to be clear: that is not a linear tech part number at all. That would be LT1007ACN8) Here is a scan of the ti linear products dats book from 1992:http://bitsavers.informatik.uni-stuttgart.de/components/ti/_dataBooks/1992_TI_Linear_Circuits_Data_Book_Vol_1.pdfIt's just a long discontinued part that TI has removed from their web site.

author: Benta
author_rank: Super Contributor
timestamp: August 24, 2025, 03:16:29 pm
content: Nothing suspicious about "TAIWAN" on the rear. It's the assembly plant (not the wafer plant).Very common are also Malaysia or Philipines.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 24, 2025, 08:53:10 pm
content: Quote from: Benta on August 24, 2025, 03:16:29 pm"TAIWAN" is not suspicious, please don't try to play a wise arse.What is suspicious is the manufacturing date and whatever is after that. The "2316VST" obviously does NOT mean something manufactured in 1990s. It is week 16 of 2023 (most likely) or week 23 of 2016 (unlikely). Dunno what that "VST" means.I don't know if it is TI that still secretly manufacturing those or might be an initiative from an overseas factory that stole the data and decided to make those theirselves. TSMC had some Lattice parts made by theirselves but those used different letter prefix. Maybe plain fake after all.

author: nctnico
author_rank: Super Contributor
timestamp: August 24, 2025, 09:42:57 pm
content: Again: please post a photo of the chip instead of making wild accusations and assumptions. Getting a fake is highly unlikely; the part you have bought a like a jellybean opamp. No profit to be made for fakers.

author: Benta
author_rank: Super Contributor
timestamp: August 24, 2025, 10:17:23 pm
content: QuotePipe down and save that kind of language for your "TRUTH SOCIAL" account.We're trying to help here.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 24, 2025, 10:42:25 pm
content: Quote from: Benta on August 24, 2025, 10:17:23 pmTo help with WHAT? Did I ask for any HELP?Here are the photos, the best I can do with my camera. Have to setup a camera in my Lynx microscope but it would take time I don't have...

author: amyk
author_rank: Super Contributor
timestamp: August 25, 2025, 02:05:35 am
content: Quote from: ejeffrey on August 24, 2025, 01:59:11 pmHere is just the datasheet:https://www.alldatasheet.com/datasheet-pdf/pdf/209434/TI/LT1007ACP.htmlIt has 1989 and 1993 dates, and the PDF was probably created in 1999.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 05:03:21 am
content: Quote from: amyk on August 25, 2025, 02:05:35 amThe datasheet says it's been created in February 1989 and revised January 1993. The PDF creation date is irrelevant.There is _NO_ LT1007 ANYWHERE on TI website and website search for LT1007 returns just 3 hits all of them being "What TI part can be used as a substitute to LT1007?".That means that _IF_ they ever made LT1007 part, that was SO LONG ago that it never got to the web site at all -- it is very difficult to remove _ALL_ mentions of something from the entire website if it was there. There would be some dangling links, missed references and so on. If it EVER was on their web they made an _EXTREMELY_ good job removing any traces of it. If it had been a crime scene that would've made it almost a perfect crime.However, regardless of those true or false pieces of history, the chips I've got bear 2023 production date as you can see on the photos I posted. 1993 was 32 years ago so something could've been forgotten and wiped out. 2023 was only 2 years ago and it is NOT ancient history.It is either a massive fake (don't fall for "it is too cheap to be worth faking" -- they even fake ten cents apiece capacitors) where the wrong production date is a red flag or a massive conspiracy from TI. I would assume chances of counterfeit parts being 99.99% with remaining .01% left for TI conspiracy.The $1E6 question is have Rochester been duped in taking truckload of fake parts or are they WILLING participants in that scheme.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: August 25, 2025, 05:09:41 am
content: Next step: have one decapitated.I can suggest Richard Kaussler of Monacchium, West Germany. He is an associate of mine and works for free, but the disadvantage isa) he is overloadedb) you need to send the part to West Germany by the postIf you want to, I can set you up with him. Shoot me a private message here with your email, and we can take it from there.In general, however, Rochester is from my experience a class act. If these were fakes, and we can prove it, they would pay you a Rabbis ransom in compensation.

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 25, 2025, 06:28:33 am
content: even from the pictures, it looks like a genuine TI product.TI's markings have always been complicated and strange.similar markings on the front and back are often seen on older devices.Rochester is listed as a source for obsolete devices on ti.com's Wayback Machine least 1996.https://web.archive.org/web/19961220005735/http://www.ti.com/sc/docs/psheets/obsolete.htmWhy should we be suspicious?LM393P in my parts box.it from my father when I was little, so it's at least 15 years old. from the packaging, probably from the 90s. it has the similar markings.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 06:36:29 am
content: Quote from: squadchannel on August 25, 2025, 06:28:33 amBecause of a recent production date? Can you explain how could one derive something like 1990-ish from that "2316VST"?

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 25, 2025, 06:44:50 am
content: There are several documents related to marking codes, but they all explain completely different codes.I am not sure if it is a genuine product, but I have a chip that uses a similar marking system.Markings are not always four digit year-week codes.two digit week and one digit yearalphanumeric year codeswithout week(year) codessome codes are fab plants or rohs compliant markingsThere are no standards.

author: amyk
author_rank: Super Contributor
timestamp: August 25, 2025, 06:52:35 am
content: Not every IC TI makes has information on its website. But at one point, the LT1007 was there, as evidenced by its datasheet having been archived 25 years ago:http://web.archive.org/web/20000207202100/http://www-s.ti.com/sc/psheets/slos017c/slos017c.pdfMaybe TI decided to stop advertising it but continued making the part for Rochester.

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 25, 2025, 07:02:02 am
content: so, did you ask Rochester about When/where it was manufactured. it should be written on the box that the rails came in.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 07:30:18 am
content: Quote from: squadchannel on August 25, 2025, 07:02:02 amI'm not buying from Rochester on a regular basis. This was an accidental purchase, top off to make their $250 minimum. I usually buy from Arrow, DigiKey, some others that don't have minimums and are trustworthy. That is for my own stock that I have pretty extensive as well as tons of measurement equipment and tools -- I work 100% from home. The company I work for is totally different -- many of our devices are made in hundreds of thousands (a thousand is a small quantity or a trial run) and they are definitely built not here and the purchasing is also done by a special department here and there. They have a list of approved vendors and Rochester is definitely not even near that list. I simply design those devices and build prototypes right here, at home that is why I have a vast, very diverse stock of parts so I could be able to build almost anything. Only more expensive parts kinda like Stratix 10 FPGAs and such are purchased by the company; I don't buy even single quantities. Almost everything else I have in stock.Methinks Rochester turned itself into a marketplace for anybody to sell anything under their umbrella for a hefty commission. Kinda like Amazom became from their original state. My guess is those parts came from one of their marketplace sellers.

author: tom66
author_rank: Super Contributor
timestamp: August 25, 2025, 08:39:44 am
content: Rochester's gig is either buying unpackaged dies or sometimes packaged parts at EOL from semiconductor manufacturers or in some cases porting the process and design over from that manufacturer who doesn't want to make it any more.In that sense the parts are not guaranteed to beoriginalbut they've always seemed to be technically competent as a company and assure that the performance of the devices are as close to the datasheet as possible. I have spoken with some of the technical contacts at Rochester and they have been highly knowledgeable and resourceful regarding a part we purchased from them, down to being able to answer specific questions about enable pin hysteresis that wasn't specified in the datasheet.It's a 30 year old part and they're keeping it in stock for $5 a piece. Meanwhile a part we want was being scalped at $200 a piece, normally $8, by Chinese vendors that had just bought up as much of the inventory as possible at EOL. I'm positively glad companies like Rochester exist, and that TI, ADI and others sell their end of life inventory and sometimes IP off to these guys.

author: wraper
author_rank: Unknown
timestamp: August 25, 2025, 08:55:21 am
content: Looks painted (blacktopped), rub it with acetone or other strong solvent. Terminals look like they could be cut off and new ones welded on. Though cannot say for sure under the angles pictures were taken. These could be relabeled parts salvaged from e-waste.

author: nctnico
author_rank: Super Contributor
timestamp: August 25, 2025, 09:10:18 am
content: Quote from: squadchannel on August 25, 2025, 06:44:50 amAgreed. It seems TI doesn't use date codes but lot codes so they have some traceability of the chips and make it hard for counterfeiters to produce chips with a valid lot code. I have a very old TI chip here which has a code '549BA' stamped on it. Nothing resembling some kind of date code.

author: xvr
author_rank: Frequent Contributor
timestamp: August 25, 2025, 01:38:37 pm
content: Rochester not only supplies EOL semiconductors, but also licensed EOL semiconductor manufacturer from many companies. They buy licenses and the original technology from the original manufacturers and continue to manufacture EOL chips under the original brand.So your LT1007 could be manufactured by Rochester itself in 2023 under the TI brand.https://www.rocelec.com/solutions/licensed-manufacturing

author: wraper
author_rank: Unknown
timestamp: August 25, 2025, 02:24:57 pm
content: Quote from: xvr on August 25, 2025, 01:38:37 pmWhere does it say they would put an original brand onto the part? Licensing the part and branding put onto it are two different things.

author: xvr
author_rank: Frequent Contributor
timestamp: August 25, 2025, 02:53:41 pm
content: QuoteThey don't say - this is just my guess. They say that they take everything from the original production, maybe this is also branding?After all, let's take TSMC for example - they do not put their brand on all the chips they produce.

author: wraper
author_rank: Unknown
timestamp: August 25, 2025, 03:48:56 pm
content: Quote from: xvr on August 25, 2025, 02:53:41 pmTSMC does not buy licenses for the chips, they are a contract manufacturer. Also they usually do not even package the chips, just produce wafers. Barely any company will allow their branding to be used by another party. Those which do usually are companies which base their business on franchising or merchandising, or sold off their branding due to a tough situation they got into.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 05:19:38 pm
content: Quote from: squadchannel on August 25, 2025, 06:28:33 amIt is not the same. It has 3 lines of marking and what the manufacturing date is made of too many numbers. Those LT1007ACP have 2 lines of markings and the production date is quite clear 4 numbers that is usually 2 digits of year and 2 digits of the week. Dunno what that "VST" means.

author: nctnico
author_rank: Super Contributor
timestamp: August 25, 2025, 05:27:51 pm
content: Actually it is the same: a lot code with 7 positions.Look here where the 7 digit lot code is mentioned by TI:https://www.ti.com/support-quality/faqs/customer-returns-definitions-faqs.html

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 05:28:17 pm
content: Quote from: wraper on August 25, 2025, 08:55:21 amThe marking is laser etched, it doesn't go off with acetone or whatever. The terminals do not look like they are welded over. It looks like a relatively new part, definitely not like something 30 years old. Packaging quality is very good, almost too good. Terminals are not oxidized, still have that electrolytic (?) tin on them almost like new.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 05:31:11 pm
content: Quote from: nctnico on August 25, 2025, 05:27:51 pmOnly 4 of which are numbers with some letters at the end. It IS different. Those 3 letters might have some meaning if it is not a counterfeit.

author: nctnico
author_rank: Super Contributor
timestamp: August 25, 2025, 05:40:28 pm
content: Lot code can be any combination of letters and numbers. You are getting worked up over nothing.

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 25, 2025, 05:54:25 pm
content: Quote from: ksilabs on August 25, 2025, 05:19:38 pmI mentioned. not usually.Quote from: squadchannel on August 25, 2025, 06:44:50 am

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 06:17:14 pm
content: Quote from: xvr on August 25, 2025, 01:38:37 pmThere is a $1E6 question -- why manufacture a long dropped clone of other manufacturer's part that is still in production by the original manufacturer and readily available? It is NOT an obsolete or EOL part so why bother?

author: wraper
author_rank: Unknown
timestamp: August 25, 2025, 07:16:05 pm
content: Quote from: ksilabs on August 25, 2025, 05:28:17 pmI'm not talking about the marking about about what's underneath it. Coating the surface with a black paint it common practice used by counterfeiters. If an acetone soaked swab becomes even slightly black after strong rubbing the chip (sometimes it does not come off, especially if it was heated to a high temperature), it's a sign it's blacktopped.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 07:50:39 pm
content: Quote from: wraper on August 25, 2025, 07:16:05 pmNah, aceton/MEK/dimethylformamide does not affect it. Didn't SOAK it with DMF as that makes epoxy swell but short wiping with it doesn't affect it.The packaging is very good and those seem to be of recent manufacturing -- lead-free electrolytic (?) tin on its leads is still bright, no sign of oxidation from a long exposure to oxygen as it would be obvious on an old part. I also don't think they made it lead-free tin in 1990s but might be wrong.

author: wraper
author_rank: Unknown
timestamp: August 25, 2025, 08:02:05 pm
content: Could you post a photo of face of the terminals from inner side? It looks like they could be welded like on the picture below, but it's not clear from the pictures you provided.

author: wraper
author_rank: Unknown
timestamp: August 25, 2025, 08:15:01 pm
content: BTW you could measure with multimeter in diode mode if there are reverse parallel diodes between its input pins. A quick test to rule out that it's an opamp with vastly different input stage.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 08:23:31 pm
content: Quote from: squadchannel on August 25, 2025, 06:28:33 amBTW, this one has tinned leads, definitely leaded like they all were back in the days. Those LT1007ACP I've got have newer style electrolytic (?) lead-free tin finish that is usual for relatively recent lead-free parts.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 25, 2025, 08:31:15 pm
content: Quote from: wraper on August 25, 2025, 08:02:05 pmNope, the leads are not welded, the package itself including leads is of a very good quality, better than many of recent genuine parts.Damn, has to setup that camera in my Lynx microscope so I would be able to take under-the-microscope images... Have camera installed, just need to connect it over USB and get/setup some software.

author: nctnico
author_rank: Super Contributor
timestamp: August 26, 2025, 09:46:18 pm
content: If you have a reasonably modern smart phone, use that to make close up pictures. My Samsung is surprisingly good at taking images of small objects with high magnification factors. Sometimes I used it as a magnifier.

author: ksilabs
author_rank: Regular Contributor
timestamp: August 27, 2025, 12:38:52 am
content: Quote from: nctnico on August 26, 2025, 09:46:18 pmI don't use smart phones. I know what's inside to the very guts of those -- I do side contracts porting that, sorry for an obscene word, Android to various new devices -- and for many other reasons.I have several Vision Engineering Lynx microscopes here, one fitted with a camera attachment and a 4K USB Camera, just have to setup some software to take images from it. That one even has a rare "Opaque Viewer" or whatever it is called, the thing that goes around the object and lets you see it from different angles without moving it. I wish I had time for that...