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Thread: Fake ICs

  1. #11
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    Quote Originally Posted by Hugo Holden View Post
    ...
    There was another clue here too, about a likely fake scenario "I got 10 of these today". Those sorts of numbers for a rare IC are very suspicious. Occasionally a batch of NOS rare IC's comes up, but when they do, the seller will make a big deal about the new old stock nature of them, and carry on like somebody stumbled across a Porsche Spyder in an old disused farmhouse in the midwest hiding under some bales of hay.
    This is mostly very true, and really it is excellent advice to follow almost all of the time.

    However, I have experienced a case where I purchased a fairly rare chip in quantities of 10 a couple of times, and they were not re-marked (and were priced low compared to a UK seller who wanted way too much, just like you said!). The chip in question was the Zilog Z280, and the seller was UTsource. Each of the chips had different data codes, were obvious pulls, and had old-looking stamping. After a few lots like this among the small Z280 community on retrobrewcomputers.org, Plasmo (who is on VCF as well) got a lot with a uniform date code, across the lot, that was pretty obviously fake (the date said '1525' but Zilog definitely wasn't fabbing Z280's in 2015!), but they did work ok, at higher than rated speeds, even. So, if the cost is low, buying a small lot to check won't hurt, and you might find the real thing, as I did with the Z280. If the chip and its system are rare enough, building a test jig to check the chip outside the rare system is a really good idea!

    But I got a lot of a few 20MHz CMOS Z80's that turned out to be NMOS Z80H chips that were re-marked; for the Z80 there is a software test that can be done to distinguish between NMOS and CMOS parts reliably, and all 6 of the chips I purchased from that seller tested as NMOS, not CMOS, and all 20MHz-rated Z80's are CMOS. I bought two from a different seller that passed as CMOS, and look to be genuine. Chip faking is a relatively low-cost and apparently lucrative business.

    Your good advice stands, but I just wanted to mention I have had at least one time where I got the real deal, 10 at a time.

    EDIT: So, where would one get pulls of a rare Z280? A company named Specialix made an ISA multiport serial card called the SI/XIO-H that used a Z280 for the control processor; a bit of trivia is that the Linux kernel with the driver for this card enabled actually has Z280 binary code embedded in it for this card's firmware; they show up on eBay frequently, such as https://www.ebay.com/itm/New-Special...cAAOSwzVhbVmnT
    Last edited by lowen; September 12th, 2019 at 05:50 AM.
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  2. #12
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    Yeah. Interestingly, they appear to be producing video:

    20190911_212241.jpg

    It isn't coming out on the Hyperion's own screen, but that could be a problem in circuit.

  3. #13

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    Oh they're fakes: they make upside-down video!

  4. #14

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    Quote Originally Posted by falter View Post
    Yeah. Interestingly, they appear to be producing video:

    20190911_212241.jpg

    It isn't coming out on the Hyperion's own screen, but that could be a problem in circuit.
    Well there is a chance that they could be a re-labelled equivalent part that somebody knows is an equivalent. For one example the character generator in the Sol-20 does have an equivalent part similar enough to work, with a different number. If that is the case they might be ok or possibly re-labeled to improve their appearance. So in this case you may well be ok.

  5. #15
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    Is it possible they could take old stock parts, and relabel them with the intent of freshening them up for sale, with 'production' dates being substituted for warranty start dates? The date code on these doesn't look like any that I've seen on SMC chips, unless they switched to another system later on.

  6. #16
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    I recently ordered a couple suspiciously-cheap NEC V-20 CPUs that were advertised as 16Mhz parts. They have beautiful clear markings on them and have obviously been "refurbished" from pulls (the chip legs are tinned with solder, and one of them looks like it *may* have actually had a pin repaired so I have some reservations regarding whether or not they're actually 16mhz units. But since my machine can only run them at 7.16mhz and they appear to work fine at that I don't suppose I can actually claim to have been ripped off even if they're not.

  7. #17
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    The other thing you kind of wonder about is motive... these chips only cost me about $60. Hardly seems worth the effort to fake for an obscure chip few people will need or use. If it was a ceramic 6502 or something I could see much more incentive to fake there.

  8. #18

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    Quote Originally Posted by falter View Post
    The other thing you kind of wonder about is motive... these chips only cost me about $60. Hardly seems worth the effort to fake for an obscure chip few people will need or use. If it was a ceramic 6502 or something I could see much more incentive to fake there.
    The fakers are notoriously inept at faking ceramic IC's, its the epoxy case ones they can much more easily re-surface and label. So gold pins and gold top ceramic IC's in my experience are very rarely if ever faked, though possibly re-labelled. Its amazing though how good they have become at welding new legs onto transistors an IC pins and they plate over the welds.

  9. #19
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    Quote Originally Posted by falter View Post
    The other thing you kind of wonder about is motive... these chips only cost me about $60. Hardly seems worth the effort to fake for an obscure chip few people will need or use. If it was a ceramic 6502 or something I could see much more incentive to fake there.
    This is why I'm surprised anyone would worry about fakes at this level. If you're buying something particularly rare and sought after (for example some of the less common chips used for building Apple I clones to the original spec) which can be priced up quite a bit, then I'd be wary. However, if you're buying something that was made in large quantities and used across many devices, then why would anyone spend the time and effort to bother? There are far easier and less complicated ways to make money. The market for old chips isn't big enough to go through such an effort to occasionally sell a quantity of $6 chips.

    Besides which, even if they're not pulls, surely there's plenty of surplus stock out there for various processors, RAM, support chips, etc, which was produced and then superseded by newer designs before being sold, or the product for which they were intended was discontinued. How often do people find actual counterfeit chips, as opposed to bad batches?

  10. #20
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    Could it be there are old counterfit chips that were made back in the day and not sold that are showing up now? I figured most of the old chips showing up from china are just scavenged off of old equipment and cleaned up. You would be surprised how much effort they go into making a few cents in some poor areas of China.
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