Hello everyone,
I hope during this period of global uncertainty and crisis that this message finds you well.
I have made some interesting progress with the Lisa that may be of interest to some. I am
also posting to request some help in the hope of getting it up and running fully.
So recently I dug out the Lisa and decided to attempt to diagnose further the issue I was having with it. To cut a long story relatively short it basically turned on whenever power was applied (ie soft power switch not pressed) and error out at I/O error 52. I noticed that if I switched it on let it error, switched it off, wait 10-15 seconds and switched it back on, 100% of the time it would then both correctly with no error.
At the time, a few days down the line I tested the power supply and found that all the rails were as expected. However I noticed that I could remove the back and front panels triggering the interlock switches and the Lisa would not turn off. The switches were working but the Lisa was ‘ignoring’ them. With the machine booted I got it running MacWorks and when I selected the shut down from the drop down menu the system will eject the disk, dim the screen and then nothing. It will permanently hang on a dimmed screen.
So,
I then decided to switch a power supply from another Lisa into this one. Now the I/O error permanently went away and the interlock switches were functioning again as expected. Just to test I put the power supply from the 1st Lisa into the 2nd and it caused that Lisa to develop I/O error 52. Therefore there is something wrong with that power supply that is preventing the COP421 chip from working properly. I then tried with MacWorks and asked the system to shut down with the swapped power supply and it did! It fully shutdown so I thought the power button may work again but upon pressing it the computer would not start back up.
So this is the stage I am up to now. Does anyone have any ideas as to what could be causing this? I really hope it isn’t a bad COP421 chip as I know these are incredibly difficult to locate.
Many thanks,
I hope during this period of global uncertainty and crisis that this message finds you well.
I have made some interesting progress with the Lisa that may be of interest to some. I am
also posting to request some help in the hope of getting it up and running fully.
So recently I dug out the Lisa and decided to attempt to diagnose further the issue I was having with it. To cut a long story relatively short it basically turned on whenever power was applied (ie soft power switch not pressed) and error out at I/O error 52. I noticed that if I switched it on let it error, switched it off, wait 10-15 seconds and switched it back on, 100% of the time it would then both correctly with no error.
At the time, a few days down the line I tested the power supply and found that all the rails were as expected. However I noticed that I could remove the back and front panels triggering the interlock switches and the Lisa would not turn off. The switches were working but the Lisa was ‘ignoring’ them. With the machine booted I got it running MacWorks and when I selected the shut down from the drop down menu the system will eject the disk, dim the screen and then nothing. It will permanently hang on a dimmed screen.
So,
I then decided to switch a power supply from another Lisa into this one. Now the I/O error permanently went away and the interlock switches were functioning again as expected. Just to test I put the power supply from the 1st Lisa into the 2nd and it caused that Lisa to develop I/O error 52. Therefore there is something wrong with that power supply that is preventing the COP421 chip from working properly. I then tried with MacWorks and asked the system to shut down with the swapped power supply and it did! It fully shutdown so I thought the power button may work again but upon pressing it the computer would not start back up.
So this is the stage I am up to now. Does anyone have any ideas as to what could be causing this? I really hope it isn’t a bad COP421 chip as I know these are incredibly difficult to locate.
Many thanks,