Dead II+ Rev.7 motherboard

[Linards Ticmanis <ticmanis@gmx.de>]

Hello all,

I just managed to kill my Rev.7 II+ motherboard. I wanted to see if the
color burst was getting anywhere (since I suspected that it was not),
and so I removed pin 13 of the 74LS11 at board position B12 from the
socket, and temporarily connected it to what I thought was a +5V spot
(but might have been something else). The idea was to remove the HBL
component from the Color burst equation, so that I should be able to see
the burst in the picture itself (if it was there at all).

Crash boom bang, system dead. No beep on power up, no video signal.
Chips still get warm (but not inordinately so, and there was no visible
or smellable smoke, and no audible popping of anything). Replacing the
LS11 didn't help. Unfortunately I was too surprised and too much in a
rush to find the power switch to remember the exact location where I
thought I had located +5V - so maybe I was in fact leading some other
signal into the chip.

I do have a voltage meter (not in this place though, so I can't tell you
any readings yet), but no oscilloscope. How would I proceed? Replace all
the 74xx chips and hope that CPU, RAM and ROM are still alive, or is
there another way?

Unfortunately I found nothing in the FAQ on "how to check a dead Apple
board", although I think this has been discussed before.

Thanks for any help,

-- 
Linards Ticmanis