Re: Please help with IBM PS 2

Hi!

I decided to replace the battery which is built into a chip with
CMOS.

If you still have the old DS1287/887chip, try:
http://www.mcamafia.de/mcapage0/dsrework.htm

It took me a lot of tries to get into the module without destroying it.
(Hint: a sharp side cutters or file might work better than a Dremel--they
did for me...) Once I'd done it successfully, however, the other modules
that I also reworked are all still ticking.

I resoldered a pin on the old damaged SRAM, removed the new
chips, and reinstalled the old ones. Yet the exact same problem
- no beeps or other response. I'm lost as what to do. Have I
ruined the computer beyond repair?

What should my next steps be?

Anything is possible, though you should try a few steps before giving up
hope or seeking a replacement planar board. First, the power connector on
the planar is right near the SRAM and clock modules. Did you remove it? (I
had to remove mine to get enough room to work on the chips.) Is it tight?
Are you sure that A) all the pins are seated and B) that they're all going
into the right holes?

I've never tried the DS12887A, so I don't know what it might do. It's my
understanding that the 12887A is a pin-compatible part. Something about the
logic inside it is different.

If you get a chance, get the right clock module and double check to make
sure the SRAM you got is really a compatible part.

Failing all of that, and once you have a proper SRAM and clock module in
place--strip the system down to the bare necessities. Remove all expansion
cards, make sure that everything is well connected--SIMMs, power plugs,
etc..., connect the monitor to the built in VGA port (don't use the video
coming from a card installed in an expansion slot if you have one--it won't
be configured yet and you will never get any video) and try powering up.

The light on the floppy drive does come on during the power on self test
(POST). You will have to get past the memory count before this happens.

William


.

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