New olds stock (NOS) 74 ICs (advantages, disadvantages) - Page 1
Forum section: electronics / beginners

author: whatever
author_rank: Contributor
timestamp: December 17, 2023, 07:05:25 pm
content: I have come across a decent, local source of new, properly-stored (in anti static tubes) 74 logic ICs, in DIP pkg, with date codes from 1982 to 1989.They are branded National, Fairchild, "S" (Signetics?) ,etc. And county of orig is sometimes printed (Singapore, Malaysia, etc).I can purchase them in bulk at very low costs. Given some of the claimed issues with Chinese fake chips, a genuine source might be an investment -- or not.Any obvious advantages, disadvantages to this NOS stock?A possible, reasonable query might be: Does the plastic or silicon "age" over decades?Try to avoid obvious responses such as: "who wants these impractical DIP packages in the modern era of SMD".

author: shapirus
author_rank: Super Contributor
timestamp: December 17, 2023, 07:14:09 pm
content: Old computers and other equipment of that era generally still work like new (but often not before the electrolytics are replaced), so it doesn't seem like age would affect them.Additionally, they'll just be a nice piece of history, especially in the original packaging.

author: langwadt
author_rank: Super Contributor
timestamp: December 17, 2023, 07:25:56 pm
content: some old components can be pretty much impossible to solder from oxidation on the leads

author: jonpaul
author_rank: Super Contributor
timestamp: December 17, 2023, 07:27:25 pm
content: Yes have boxes of them 74HC/LS etc and Cmos 4000 circu 1970s.DIP pin plating oxidizes and can corrode in poor/humid storage.IC my be good but socket/solder may have poor contact.Easy to clean pins.Jon

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2023, 07:31:25 pm
content: Quote from: jonpaul on December 17, 2023, 07:27:25 pmEven in the best conditions the metal surfaces will have degraded over such a long period. That's bad for automated assembly, but not a big problem if they are used for repairs and restoration. Soldering by hand you can use enough flux to defeat all but the worst corrosion.

author: LinuxHata
author_rank: Frequent Contributor
timestamp: December 17, 2023, 07:39:49 pm
content: Genuine SN74141 are quite valuable, and while soviet K155ID1 is still made by "Integral" in Belarus - I have seen them with 2019 date code, still, a lot of people prefer genuine 74141s...Some specific display decoder modules from these years are used in various vintage synths and are quite valuable, since they are no longer made and no Chinese clones exist.

author: whatever
author_rank: Contributor
timestamp: December 17, 2023, 07:40:56 pm
content: Quote from: shapirus on December 17, 2023, 07:14:09 pmTheir genuineness and antique-ness certainly have some value. Like art or comic books or baseball cards.

author: whatever
author_rank: Contributor
timestamp: December 17, 2023, 07:46:24 pm
content: Anyone know of performance advantages of these older chips (over ,say, newer direct replacements). Maybe better S/N, or cleaner wave patterns on o-scope or spectrum analyzer?

author: Stray Electron
author_rank: Super Contributor
timestamp: December 17, 2023, 07:59:58 pm
content: Quote from: langwadt on December 17, 2023, 07:25:56 pmNot only do the leads oxidize but they corrode right where the lead enters the IC body and the leads snap off easily. Ask me how I know!But it the leads are as shiny as new then the IC should be fine. A lot of people that restore MIL electronics, vintage computers, etc etc are looking for old original ICs so they may have some value. Any with ceramic bodies, gold lids, etc are collectible. Things like 4004 and 8008 CPUs are very collectible.

author: schmitt trigger
author_rank: Super Contributor
timestamp: December 17, 2023, 08:22:42 pm
content: NOS stock can be invaluable for anyone restoring vintage equipment and keeping the equipment, well, vintage. Actual price will depend on IC type. A 7400 won’t be as valuable as a 74151.If you purchase the lot, make sure that you categorize it by part number and a subcategory of manufacturers. Again, a defunct company like Signetics may have a stronger nostalgia appeal than TI.

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2023, 08:22:58 pm
content: Quote from: Stray Electron on December 17, 2023, 07:59:58 pmThis is an odd issue you see in various places. Its not just ICs. Things like knives often break where the blade leaves the handle, and you find a line of corrosion has weakened the metal at that point, with no corrosion showing anywhere else along the blade, outside or inside the handle. I've never found the mechanism for that.

author: whatever
author_rank: Contributor
timestamp: December 17, 2023, 08:51:44 pm
content: I am especially interested in fast chips. The non-low-pwr devices in particular.I did find some fast "S", as opposed to common "LS" low-power ICs in the stockpile.E.g., 74S04, etc. No "AS" series thus far.Still hoping to find elusive ECL's.Speaking of fast, anyone know an alternative source-- of same or similar products-- to this now-defunct company:https://web.archive.org/web/20190603020138/https://www.potatosemi.com/They offered GHz CMOS chips. Potato chips!

author: whatever
author_rank: Contributor
timestamp: December 17, 2023, 09:06:27 pm
content: Quote from: coppice on December 17, 2023, 08:22:58 pmIt may not just be corrosion at that transition point. The heat of plastic thermo-formming also may have weakened the metal.

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2023, 09:41:06 pm
content: Quote from: whatever on December 17, 2023, 09:06:27 pmWe have a set of kitchen knives with riveted on handles. Two of them have suffered this type of a failure, and along the crack in the stainless steel there was a lot of brown at the time they snapped. It wasn't kitchen grime. It was rust. Getting the remaining stainless steel piece out of the handle, every other part was pristine. Maybe grime collecting at that point resulted in a situation that defeated the stainless qualities of the steel. I have seen this happen before on other kitchen knives in the past.

author: Benta
author_rank: Super Contributor
timestamp: December 17, 2023, 10:00:13 pm
content: Quote from: whatever on December 17, 2023, 08:51:44 pmECL don't have 74 part numbers.For the potato chips, ON Semiconductor comes to mind.

author: coppice
author_rank: Super Contributor
timestamp: December 17, 2023, 10:25:52 pm
content: Quote from: whatever on December 17, 2023, 08:51:44 pmHow elusive? ECL10k was common enough that there should still be quite a few parts around, if you can find them. I expect the other families will be hard to find.

author: langwadt
author_rank: Super Contributor
timestamp: December 18, 2023, 12:34:08 am
content: Quote from: whatever on December 17, 2023, 07:46:24 pmfor logic the only thing I can think of is them generally being slower, old gear might not work with new faster logic, because routing and supply bypassing wasn't design with those in mind

author: rsjsouza
author_rank: Super Contributor
timestamp: December 18, 2023, 12:47:09 am
content: As others have said, the vintage computing crowd is usually interested in older discrete logic ICs to repair computer boards. Anything "S", "LS" or "F" is more mainstream and therefore has higher demand, while the ECL/PECL is a bit more tailored to larger minicomputers and mainframes.

author: schmitt trigger
author_rank: Super Contributor
timestamp: December 18, 2023, 12:52:42 am
content: Now, if you find some HTL high threshold gates, that would be indeed a rare find.In the whole of my 46 years as an engineer, I remember seeing HTL gates only once in the wild. On a multitrack professional audio tape recorder.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 18, 2023, 01:27:06 am
content: Some of these older chips may be victims of purple plague, corrosion of the aluminum metallization on the chips. But this problem wasn't really that common.While there is a market for these chips, it is not something that is going to set you up for retirement. There are three general ways to recoup your investment if you do buy in. Reselling the lot at a markup by being a better advertiser marketer than whoever you are buying these from. Least amount of work, but also unlikely to make much profit. Second, selling these to people doing repairs on old equipment. You could mark them up a fair amount in this market, but have to do all the labor of sorting, advertising, packaging and shipping usually in small quantities of less than a dozen. You will find after doing this for a while that you are really earning the markup. Finally, you can put together kits, either as repair stock, or to make some digital project that you think will appeal to someone. Markup will vary, and work is significant.

author: whatever
author_rank: Contributor
timestamp: December 18, 2023, 03:43:44 am
content: Quote from: schmitt trigger on December 18, 2023, 12:52:42 amYes, my ultimate interest in these "vintage" chips is audio devices -- notably, older DIGITAL gear. Specifically, CD players and digital (pro) recorders from the mid-1980s. They have attracted some '"audiophile" attention recently.Logic chips are used re-clocking and buffering the clock signal or I2S lines.Now whether data rate of PCM or RedBook digital audio can benefit from faster "S" chips or slower (certain) "HC" devices, I'm not sure. It may be that cleaner, slower (PPL propagation delay) chips are better after all.The "S" variety are not common in audio. That said, the Potato Semi devices attracted some attention on DIY forums, years ago.

author: jfiresto
author_rank: Frequent Contributor
timestamp: December 18, 2023, 08:53:17 am
content: Quote from: coppice on December 17, 2023, 09:41:06 pmThe alloys that will keep a sharp knife edge (e.g., 18/0 instead 18/10) are considerably less corrosion resistant. Sometimes I think stainless steel should have been called stains-less steel.

author: Dan123456
author_rank: Regular Contributor
timestamp: December 18, 2023, 09:21:01 am
content: If they are super cheap, I reckon go for it! If they have been properly stored, I wouldn’t imagine too many could have gone bad surely!That said, what do you mean by “investment”? Do you mean to sell them on at a profit? Or more an investment in the sense that it saves you wasting time and money on fake chips / finding genuine chips in the future?If they are only for hobby use and its only something like 1 in 20 is a bit sus, it could still be well worth it depending on priceAs for any corrosion, you could try giving those ones a soak in a dilute acid solution to remove it. You can usually buy 1L of hydrochloric acid from the hardware store in most places for bugger all - then make maybe a 1:50 acid to water solution, dunk chip, rinse off. Repeat or soak chip for a little longer if needed etc. HCl shouldn’t attack the plastic or silicon.If only a few of them have issues, and you can end up rescuing a few of those, could be worth it!Edit: actually, painting the dilute solution on to the leads with a little paint brush might be a better idea. Just in case there are any small gaps where the leads go into the die as those tiny fine wires could get eaten quick if they are made of aluminium or something!

author: retiredfeline
author_rank: Frequent Contributor
timestamp: December 18, 2023, 10:54:00 am
content: Realistically I think nearly of them will work but you'll find only a handful that you end up using. Whether that, the hours of "fun" trying to dispose of the rest, and any returns, are worth what you pay, only you can say.

author: Gyro
author_rank: Super Contributor
timestamp: December 18, 2023, 07:57:01 pm
content: Quote from: Dan123456 on December 18, 2023, 09:21:01 amEpoxy packaged ICs (and packages in general) are by their nature not hermetic. Any solution you paint on the outsidewillmake its way inside.

author: Dan123456
author_rank: Regular Contributor
timestamp: December 19, 2023, 01:17:54 am
content: Quote from: Gyro on December 18, 2023, 07:57:01 pmYeah, that why I changed it just to the leadsI figured dunking them might be slightly too risky!That said, I can’t imagine painting it on the bottom of the leads to remove the oxide from where the solder goes would be a terrible idea if you are just trying to rescue some already “dead” chipsPlus, dilute HCl will only really attack aluminiumI wasn’t sure if those chips use any aluminium wires inside but if it is all copper, gold, tin and even iron, it shouldn’t hurt it at all / muchEdit: again, to clarify, only in a hobby situationThis would likely be a terible idea in a professional setting!

author: coppice
author_rank: Super Contributor
timestamp: December 19, 2023, 06:56:51 pm
content: Quote from: Dan123456 on December 19, 2023, 01:17:54 amIf you wash the flux off a PCB with a solvent, you clean off most of the corrosive flux. However, the solvent might help a little of the flux penetrate into microscopic gaps, like the device lead to plastic case gaps, where in the long term it might cause serious damage. I've seen a few cases where something like this appeared to have happened, but I don't think its common.

author: whatever
author_rank: Contributor
timestamp: January 12, 2024, 03:46:27 pm
content: deleted.

author: SeanB
author_rank: Super Contributor
timestamp: January 12, 2024, 06:14:09 pm
content: Chips from the 1980's will use either gold or aluminium bond wires in the package, and you will also find a mix of leadframe bases. Some used Kovar alloy, some used copper alloys, almost like a brass, and some used a steel leadframe. All were tinned during production, and were punched out of the strip after tinning, leaving the edges of the pins bare. Then after packaging some were tinned again, to get fully tinned leads, and some just were left bare. All depending on who made it, and which process machinery they used. Only thing you can be sure of is that they will all need baking to remove moisture from decades of exposure, done slowly, to avoid popcorning, and then storage in hermetic packaging afterwards, probably with a full DC test on each one after the bake, to weed out those that have failed silently in storage.As the assorted manufacturers produced them literally around the planet, in various fabs, there is no one size is right, just that you likely will need to clean the pins before soldering, generally using a light abrasive, just before insertion, and not to dip them in any acid, as this will absolutely wick up the leadframe and eat away the bond wires, and also the top interconnect layer on the die as well.

author: coppice
author_rank: Super Contributor
timestamp: January 12, 2024, 06:56:58 pm
content: Quote from: SeanB on January 12, 2024, 06:14:09 pmIf you've worked in semiconductors, and been through "what needs doing to product X to be fully RoHS complaint" you'll know an amazing number of things go into the typical lead frame. Its amazing how many elements and layers there are. They look so simple, but they are not.

author: whatever
author_rank: Contributor
timestamp: January 14, 2024, 02:29:56 am
content: Quote from: coppice on January 12, 2024, 06:56:58 pmAre you suggesting RoHS compliance affects a totally sealed device like an iC? Where not using lead might affect the reliability and longevity of the device.Use and non-use of precious metals is interesting.How else has IC fab, manuf and design economize, such that older versions are, indeed, superior?

author: Kim Christensen
author_rank: Super Contributor
timestamp: January 14, 2024, 03:24:47 am
content: Quote from: whatever on December 18, 2023, 03:43:44 amI doubt you'd find many CD players and digital recorders from the 1980's using plain old 7400 series TTL chips.74LS00 series came out in the 1970s and the 74HC00 in the 1980sso those would be a better bet.

author: coppice
author_rank: Super Contributor
timestamp: January 14, 2024, 04:19:33 am
content: Quote from: whatever on January 14, 2024, 02:29:56 amWhy would a material being sealed inside a case affect its RoHS status? RoHS is mostly about toxic materials getting into the environment when the product is disposed of at the end of its life. Few things shed very much toxic material during their working life these days. We are well past toxic finishes, like lead paint, which get abraded and shed in day to day use.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 14, 2024, 04:29:11 am
content: Quote from: coppice on January 14, 2024, 04:19:33 amHush your mouth. We don't use logic on this subject. Fear and other emotions are the usable metrics.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: January 14, 2024, 12:41:15 pm
content: I use quite a few old ICs for repair and projects. Some have been given to me. Some I have purchased.Corrosion is not usually a problem. Most of my ICs are pretty clean.Sometimes I have to clean the pins with a pencil eraser. Then wipe with alcohol. Makes soldering easier,I mostly use sockets for the ICs but cleaning the pins is still necessary sometimes.The non CMOS ones are not very static sensitive but tubes are a good way of keeping them anyway.I really do not see any advantage in using the old ICs except in replacement like repair. Even then the CMOS ones usually work as replacements.But if they are CHEAP you may find some projects for them. If you repair old stuff, they may be useful. In my experience. they work just fine, I do not see any degradation of the chips over time.

author: whatever
author_rank: Contributor
timestamp: January 16, 2024, 07:38:16 am
content: Quote from: Kim Christensen on January 14, 2024, 03:24:47 amActually, there are so many examples of their use, well into the late 1990s (and in DIP packages, too!!), that I've lost count.E.g. one example of how Cambridge Audio (Cambridge, England, UK) used mod boards, fulla 7400s, to soup up a Philips-based cdp:http://www.lampizator.eu/lampizator/references/Cambridge%20CD2/CD2%20cambridge%20Audio%20CD%20player.htmlHINT: Audiophool "theories" are completely illogical and beyond the pale. The 7400 "S" series at higher Vcc voltage use/requirements is part of the magic.

author: Kim Christensen
author_rank: Super Contributor
timestamp: January 16, 2024, 04:33:17 pm
content: Quote from: whatever on January 16, 2024, 07:38:16 amAll I see are 7400LSseries. I don't see an S type in those pictures at all.

author: whatever
author_rank: Contributor
timestamp: January 17, 2024, 06:40:44 am
content: Quote from: Kim Christensen on January 16, 2024, 04:33:17 pmGo back and read what you noted earlier. And make it habit of re-reading your own words before posting weird replies.Nota bene:Quote

author: Gyro
author_rank: Super Contributor
timestamp: January 17, 2024, 11:50:43 am
content: One old logic family that is worth putting straight in the bin is 74C00 series. They weren't around for long but I've found a very disproportionate failure rate of these in old test equipment. Strange as I would have expected them to be similar in reliability to old 4000 series parts (which seem very reliable). Luckily they can usually be replaced by 74HC00 series, as long as you watch out for any potential issues caused by their faster propagation delays.

author: rsjsouza
author_rank: Super Contributor
timestamp: January 18, 2024, 06:15:35 pm
content: IIRC the "C" devices were so terribly slow that this family was very short lived. But I don't necessarily remember them being specially fragile when compared to the 4000 series, but perhaps it was my own limited sample size.