A500 Green screen problem

[dougal]

The other day i went to use 1 of my A500s .

I switched it on and only got a black screen .

I removed the trapdoor expansion and it worked perfectly . But with the expansion inserted it gave a blank screen .

Stupid me , i thought the expansion might have been upside down , so i inserted it the other way and i got a Green screen and flashing LED , after a few seconds it reboots and gives the same screen (green) .

I removed the expansion and its still giving me the same problem .

Did i destroy my chip ram ?

Anything i can do or try ?

Here is the spec:

A500 512Kb Chip Ram
Kickstart 2.04 (Pulled from a damaged A500+)

[slayer]

hmm, I think you zapped the actual kickstart roms by the sound of that...

[dougal]

hmm, I think you zapped the actual kickstart roms by the sound of that...

If its the Kickstart ROM i dont mind ... Ill just replace it (I have spares) .

I just hope its not the CHIP MEM

[chiark]

Try to reseat all the chips internally - agnus, denise, cias, 68000, kickstart...  Green is supposed to indicate an error in chip RAM, but as all the custom chips sit on the chip RAM bus it could be one of them.

Fingers are crossed for you.  I can understand how plugging in upside down would fry your expansion, but it shouldn't take out the chip ram...  Although saying that, it's on the bus...  and you could have pulled something to ground that shouldn't have been pulled to ground...  But chips should survive that.

Good luck.!

[CLS2086]

Hi,
1st - desoxyde all chips and support with a good spray cleaner
2nd - check the 3 voltages +5 + 12  -12

[dougal]

Now It is a YELLOW screen ... I changed the Kickstart , i tried both 2.05 and 1.3 and now yellow screen .

I tried replacing the CPU and reseating and switching the CIA's and reseated the PAULA .

Nothig works

[amiga92570]

How did you plug the expansion in upside down?:confused:

[orange]

I think you should do the testing with KS1.3 and all known good chips.
but is it really worth it?
I mean, you could damage the chips with all that testing and A500(motherboards) are really cheap. Those are most common Amigas, AFAIK.
It might be better to save the parts for A500+/A2000...

[CLS2086]

"I tried replacing the CPU and reseating and switching the CIA's and reseated the PAULA."

I said use a spray cleaner...
and in some case you must use a brush on the chips and theirs supports.
Light oxydation isn't easy to see.
Sometime I need a magnifier glass to see which support pin is corroded..