I put it away working about 2 years ago give or take.
This week I wanted to fire it up aaaaaaand: the only thing I get are 3 long beeps, a pause and so on.
Put in my diagnostics card, all leds are on and the codes go from 13 12 to 00 13 and it stays there while it keeps beeping
It's an AMI bios labeled 1986-1990.
The board has not much markings on it except P23T. It has an Opti chipset and is ISA only.

What have I tried so far:

* Remove VGA card and controller card
* Reseat all RAM sticks (8 30-pin ones)
* Tried 1 bank at a time, switched the 2 sets over, tried a few other sticks I have (don't know if they work though), removed all memory
* The external battery is dead so I briefly hooked up 2 CR2032 in an adapter but nothing

Any more ideas or help concerning the BIOS codes?