Amiga 500 woes (Green screen)

[macroexp]

Hi all -

I have an Amiga 500 (not +) that I've been using for years, and I just unpacked it after a recent move. Powers up to ... green screen of death.

I've never seen this before, but I looked through posts here and tried the suggestions. First I pulled the Adram 540 board, next pulled the interposer board that it hooks up to (under Paula), reseated everything reseatable (including Agnus) but all to no avail.

So, since green means chip ram, is my only other possibility that the chip ram itself is bad? Is there anything else I can do to pin it down to that? I have enough old video cards and things lying about that I think I can scrounge replacement ram chips, but I'd rather exhaust all options before applying the soldering iron to the poor girl.


Cheers,

Mike

[macroexp]

This page, http://amiga.resource.cx/exp/search.pl?product=AdRam540&company= , says the interposer goes under the Gary chip (Uh-oh).

Seriously, I think I would gently pry up all the chips most of the way, sparingly apply contact cleaner, and reseat.  It might not hurt to check for swollen caps and make certain the battery has not leaked and contaminated anything.

If you have to replace ram chips on the MB, maybe consider upgrading to 1 Meg of chip ram.  The AdRAM seems to allow this.

Oh, duh, you're right, that's Gary there not Paula. I'll give contact cleaner a shot before I dig in.

If I do end up replacing dram chips, I'll do the 1 Meg upgrade - the board is a rev 6a/8372a so it's ready to go. Otherwise, the board looks perfect - not a bulging cap nor a speck of dust in sight.

[macroexp]

Well, I got some DeoxIT and went through some cleaning, to no avail. I googled some more and found this document describing a "piggyback" procedure. I pulled a DRAM from the AdRAM 540 and went thru them - bingo - when piggybacked on the third DRAM, U17, no green screen, and a happy hand asking for a floppy.

I'll probably just swap this chip in for now, and refill my AdRAM later.

BTW, on the 1MB upgrade - do I really need to put 4 more DRAMs on the motherboard, or can I just jump JP2? My impression is that this will make the first 512kb on the AdRAM behave as chipram (because it already is in the correct place address-wise?)

Thanks all,

Mike