Lisa won't stay off (was Lisa 2: Bad Disk Drive)

From: James MacPhail <uo957_at_email.domain.hidden>
Date: Fri, 11 Nov 2005 15:33:06 -0800

This was an aside to another problem, so it looks like it didn't get any attention:

>when I switch the Lisa off, it goes off then on immediately.

I have seen a couple of causes for this problem, ones that come to mind are:

  1. Damaged (broken) traces on the I/O Board due to corrosion from leaking batteries.

If your I/O Board once had batteries on it, check the continuity of the traces in that area carefully.

If it still has batteries on it, you should probably remove them and clean the circuit board in that area before battery leakage causes (more) damage.

The battery is not required for startup or operation of the Lisa; it is only to keep the clock running and preserve some preference settings in RAM. Unlike a modern computer whose clock can run from the battery for years with no external power, the Lisa battery only lasts for a few hours when external power is interrupted.

2) Bad COPS, or perhaps poor contact with its socket.

It may be enough to remove and re-insert the COPS to improve the connection.

If not, replace the COPS with one from another I/O board... if it still doesn't work, then it probably isn't the COPS.

3) A couple of other parts on the I/O board can fail causing this sort of problem, so if the above don't help, let us know and we can start trouble-shooting.

Good luck!

James

James MacPhail                   "Think not of engineering as art,
uo957_at_email.domain.hidden                 but of art as engineering"
Sigma Seven Systems Ltd.
james_at_email.domain.hidden        <http://SigmaSevenSystems.com>



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Received on 2005-11-11 15:35:15

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