28 Mar
2022
28 Mar
'22
12:19 p.m.
On 2022-02-25 16:09, js--- via cctalk
wrote:
Hi, folks.
I've a HP 9915A computer with an
interesting problem. The motherboard
utilizes a ceramic Intel D8048 chip.
The problem is that this 8048 has a
crack right across the top middle of
it, and half of the top of the chip
has begun to separate.
Powering up the machine as-is
unsurprisingly results in no
activity. HOWEVER, if I push firmly
on the cracked area with my finger the
machine starts to operate normally.
All appearances are that clamping down
the separating piece of the chip
re-establishes any broken wire
connections within the chip.
I've obtained a replacement
P8048AH. My question is: do these
chips simply swap like a CPU, or -- as
I fear -- is the 8048 a pre-programmed
piece? More simply put, is this a
repairable problem? Or am I SOL?
Any thoughts welcomed.
- John Singleton
Hi, folks. With the help of the
extremely talented people here, the far
less talented me was able to repair this
seemingly impossible problem and get the
9915 functional.
The process was to:
1) burn a new 8748 CPU with the 9915's
8048 ROM code.
I used a Data I/O 2900 for this purpose.
2) remove the remnants of the original
8048 CPU
3) install a new milled 40 pin socket
4) install the 8748 into that socket and
power-on test.
Thanks to Paul Berger, Will Cooke, and
Wayne S for their useful suggestions.
A very special thanks to Tony Duell for
offering to go to great lengths to help.
A very, very special thanks to Dave
McGuire for having done all the hard
work in retrieving the 8048's code to
begin with (which he had done already
for someone else), then providing the
8048 ROM code to me in hex format, plus
guidance on how to fix the problem all
the way through.
- John S.