30 Oct
2012
30 Oct
'12
10:11 p.m.
On Wed, Oct 31, 2012 at 12:45 AM, Alexandre Souza - Listas
<pu1bzz.listas at gmail.com> wrote:
Update: It isn't the BPROMs.
Since my trustworthy Beeprog doesn't work with the D3625 (older than
earth itself!), I had to create a small dumper to read the BPROMs:
http://www.tabalabs.com.br/outros_micros/sdk86/21.jpg
Cool. Nice to know. Mostly, PROMs are sturdy, though every once in a
while (under 5%), they do turn up bad.
So the problem is the 8086 itself, one or more RAMs
(P2142) or some
phisical problem on the board.
I couldn't find any info on the P2142 SRAMs. From the picture, they
look like 20 pin parts, if I counted right. If they are 4-bit parts,
specifically 1Kx4, does the footprint look close enough to wedge a
2114 in each socket with an adapter? What about wiring a pair of 6116
(2016) 2Kx8 SRAMs up in the breadboarding area? If that's not enough
RAM, surely a pair of 6264s would do it. Just a 16-bit path to the
bus and a simple address decoder, most likely. It's not original, but
it might get you running until you could track down some P2142s.
I will repair it! :oO
That's the spirit!
-ethan