Re: 264/TED/Plus4 Story

From: Gerrit Heitsch <>
Date: Thu, 27 Oct 2011 22:46:35 +0200
Message-ID: <>
On 10/27/2011 10:24 PM, crock wrote:
>> Same here... TED, PLA and CPU get a heatsink and I replace the ROMs
>> with properly programmed 27C128. Saves some power and therefore
>> produces less heat inside the case. So far I haven't lost a CPU. Maybe
>> the ones that are still working are not as fragile as the ones that
>> died already. :)
> I wondered that. Maybe the passivation of the cpu's is such that they
> are more susceptible to ageing once they get past the 'burn-in' they got
> in the 80's. :-)

I just remembered what I read in a forum. There someone claimed he could 
'fix' a broken 8501 by bending the 7 pins for the I/O-port (pin 24-30) 
out of the socket. That way the CPU worked again, you got the greeting 
message. Of course, unless you have 1551 floppy drive you won't be able 
use it for much.

Would be interesting if this 'fix' works with other dead 8501. If yes 
that might indicate a flaw in the mask.

>>> I found a source of
>>> 8501's in China last year and got 12 working ones.
>> Interesting... All genuine MOS/CSG, no fakes?
> I don't think so, they are a mix of production lines and manufacturing
> dates. If they are fakes, frankly I don't care - because they work!

Hm, maybe I should see if I can find any...


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Received on 2011-10-27 21:00:20

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