I just got a 2nd Lisa, a 2/5. The prior owner got the system in 1997. At
that time he removed the battery, and then packed it away... and didn't
touch it for 20 years.
The system does not power up with the original I/O card. There was some
light corrosion on the board in the battery area, I scrubbed it with some
water and vinegar and things are much cleaner now.
If I remove the COPS chip, the system powers up as soon as the power cord
is plugged in. If I put in the I/O card from my 2/10 the power button
responds normally and the system seems basically functional, though the
built in parallel port doesn't see an attached disk.
Here's some pointers James gave several years ago:
"If you've found the power switch signal is reaching the COP421 at pin
20, but it isn't turning on the power: check the COP has power (pin 9
should be approx. 5V), and check it is not held reset (pin 4 not
below 2.5V), and that pin 1 is truly connected to ground.
If you have a moderately high impedance probe, check the COP
oscillator is running (approx. 3.9 MHz at pins 2,3). If not, check
the parts/circuit connected to pins 2 & 3.
If it all looks good, and the COP oscillator isn't running or pin 24
still refuses to switch, then the COP might be bad, but triple-check
it is making good contact in the socket. "
If I put the COP from the 2/5 on my 2/10 I/O card, and put the card in the
2/5 it powers up normally. The mouse doesn't work though.
I verified all pins on the COP are connected... no broken traces and the
chip socket contacts seem ok.
The COP has +5V on pin 9, reset on pin 4 comes up to 5V when the PSU is
plugged in, ground on 1 is OK. The power button signal is getting to pin
20.
My Fluke 115 can't measure frequencies of ~ 2mhz. Pin 20 has about .15v on
it, and doesn't change when the power button is pressed.
Any suggestions of where I should look next?
Thanks!
--
Jason Perkins