[sdiy] Counterfeit chips

[Mike]

This is quite an old problem too. I have a couple of old 486 motherboards I
kept because they will run the IBM 'Blue Lightning' 100MHz chips,which don't
need fans, (in my domestic monitoring system). Everything looks fine, but
the Cache RAM is bogus. The Cache ON/OFF in the, (hacked), BIOS simply
switches the CPU write back on and off. The chips are simply plastic with
'legs'. You can remove them with no effect on the board. Another sleazy
trick from that era was Cache specc'd for a 25MHz bus, labelled as the
faster stuff. Put a 33MHz CPU in and it would fall over nastily. It wasn't
just the small companies who got caught here, either. I had Acer built
motherboards from Apricot and Ambra machines. You could enhance the Ambra's
to full DX2/66 no problem. Anything above 25MHz in the Apricots locked up.
They were virtually identcal boards. Cache off the Apricot would run at 33.
I never did work out if 25 + Cache was better or worse than 33 without.

Friend of mine bought some so called 726's on ebay. The seller couldn't take
returns if soldered, (as usual). I socketed them in an adapter for test, (I
still have a few round PTFE sockets left). Turned out they were old op-amps
re-labelled. This wasn't HKSS by the way. He got a refund after a long
haggle. The seller 'left' not long after. I wonder how many people got
bitten and thought they'd damaged them in assembly?

Mike

----- Original Message ----- 
From: "Oakley Sound" <tonyallgood at btinternet.com>
To: "Synth DIY" <synth-diy at dropmix.xs4all.nl>
Sent: Thursday, November 15, 2007 1:19 PM
Subject: Re: [sdiy] Counterfeit chips


> > it seems to me that counterfeit synth parts might have desirable
> qualities of their own.
>
> Except for the fact that may be simply re labelled chips. So, for
> example, it could be just a very expensive 74HCT274.
>
> No problems here with Chipforbrains though. Always good chips from CY.
>
> Tony
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