[vcf-midatlantic] Fake 7400-series memory

systems_glitch systems.glitch at gmail.com
Thu Aug 24 12:18:33 EDT 2017

As Dan mentioned, this is probably the result of a mistake in a legitimate,
but often poorly communicated, Chinese salvage operation. There are shops
in China that specialize in refurbished ICs, which may be old stock, board
pulls, et c. Typically the old chips get blasted clean with a mild abrasive
(often ground walnut hulls, I'm told), dipped in flux, tinned in a solder
pot, then re-etched with a current production datecode and the part number.
It kind of loses legitimacy when they put a manufacturer's trademarked logo
on the IC, though.

Having bought many hundreds of refurbished ICs from China -- usually things
that have been out of production for years -- I've found that most of the
sellers and brokers have a hard time articulating that the chips are
refurbished in terms that your average English-speaking purchaser would
understand. There are of course outright frauds. As an example, I recently
purchased 200x Motorola 6821 PIAs for the runs of reproduction OSI boards
we're working on. They were refurb/relabel ICs with a 2015 datecode. They
came with the Motorola logo etched into the top, but the seller was very
clear that they were a mish-mash of manufacturers and that the ICs were
solder pulls, recycled from old boards but tested after refurbishing. This
was 100% acceptable on hobbyist boards, and so far every single PIA has
passed test.

So, how can they sell PIAs so cheaply? I suspect they're being paid to take
eWaste, subsidized by the Chinese government to not just dump it in a pit,
subsidized on the tax/shipping since it's an export business, and they are
in the end selling the IC for money. It's like being paid to do scrap
cleanouts, but with government assistance along the whole way.


On Thu, Aug 24, 2017 at 11:49 AM, Herb Johnson via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> > On Thu, Aug 24, 2017 at 11:16 AM, W2HX via vcf-midatlantic
> > I would think the most logical explanation for [faking] this chip was not
> > that someone went through the trouble of trying to pass off one chip
> > for another, but rather that the manufacturing process simply put
> >  the wrong label on the chip.
> Here's the choices - someone in China relabeled a chip; or a semiconductor
> production assembly line for analog/digital chips, put a TTL device label
> on the chip instead? And if the latter, how did devices decades-old, which
> obviously failed any quality-control, end up available today and likely in
> some quantity?
> I think "China relabel" is more likely. There's a LOT of relabeling going
> on today. Typically, standard chips are relabeled as high-reliability
> expanded-temp chips, which is harder to detect. This fraud was stupid, at
> some level.
> On 8/24/2017 11:28 AM, Jason Perkins wrote:
>> Unless someone came across a large stash of the DTMF chips, got them for
>> next to nothing, and was trying to pawn them off as something useful.
> Neither chip is very "useful". I suppose someone making a TTL computer
> today would use a 74LS181 and some other 18X chips too. Ebay prices are one
> to a few dollars each. But who can second-guess the next person making
> money through chip fraud? This is what a race to the bottom looks like.
> Herb
> --
> Herbert R. Johnson, New Jersey in the USA
> http://www.retrotechnology.com OR .net
> preserve, recover, restore 1970's computing
> email: hjohnson AT retrotechnology DOT com
> or try later herbjohnson AT retrotechnology DOT info

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