Amiga 1200 motherboard to save!

[Chucky]

First of all..  everyone is sayinh "screen is black" but ALWAY ALWAYS *ALWAYS* forgets the interesting thing:

POWERLED!  does it change brightness after aprox 1 sec?  if not something hold the machine not able to start the kickstart..

recapping will NOT make a nonbooting A1200 start!.  
I repeat:

RECAPPING WILL NOT MAKE A NONBOOTING A1200 START.

ok with this said..

your kickstartroms MIGHT have been damaged if turned the wrong way.   if in wrong postition the only thing that willhappen is the machine be dead.
so try to get hold of another set of kickstartroms.. (or.. my DiagROM) and test

[Chucky]

Hi,

Edit: Have you tried booting with the ROMs removed?

Ehh? that would just end up in a machine with black screen, no powerled change.  simply. DEAD..

[Chucky]

Next thing is to grab an oscilloscope and test if you have all clocks.
also multimeter to check if all adress and data-lines works.

ONCE a dead machine started when plugging in an accelerator card for me. but that's only once..

[Chucky]

Well  first step of any Amiga troubleshooting is to look at that powerled.  of some reason this is always skipped as they watch on the SCREEN!.

among the very first things kickstart does it to turn the powerled HIGH, all amigas (with exception of A1000 and Rev 3 a500) starts with powerled on HALF brightness.  So. it shlud go to full brightness after aprox 1 sec.   if this doesn't happen, you either have bad kickstartroms or something that stops the machine to execute the kickstart.   this is usually the hardest things to find.

then you can use my diagrom to test more stuff like bad IRQ och CIA timers, this will also make the amiga to give "black screen" etc.    and USUALLY 99 times of 100 diagrom only starts IF that damn powerled goes full bright.

so CHECK THAT LED for hint on where to start the troubleshooting.  if it DOES go high!  your PSU IS fine.  meaning it atleast deliver 5V (and 12?) it also means that your kickstart most likly IS ok. (as it can execute the code)