HP 9915A failed 8048
js at cimmeri.com
js at cimmeri.com
Mon Mar 28 14:19:28 CDT 2022
On 2022-02-25 16:09, js--- via cctalk
> 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
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
3) install a new milled 40 pin socket
4) install the 8748 into that socket and
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.
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