A3000 don't boot (green screen)

[Mugo]

Tried a lot of things already.

When i power on, after about a second, the screen goes green for about another second, then goes black again. This continues on a endless loop. The power led also blinks in the known dimmed/full lit states, signaling a problem.

I've replaced the Fat Agnus, the Denise, Paula, and even the socketed RAM chips. Nothing changes.

I think the problem can be with the PAL chips in the memory circuitry (U202, U203, U701, U715).

Can someone experienced with this problem confirm or deny it? Any thoughts?

Also, is someone here able to provide me with spare (tested working) parts to replace these PALs? Of course, i'll pay for them.

Thanks!

[Mugo]

Err... forgot to mention the machine background.

This A3000 suffered heavy battery corrosion. Only the top copper layer was affected (as far as i can see).

Have repaired the broken traces, and replaced the damaged parts (some capacitors).

I THINK i did repaired all the damage, but who knows.

The owner, a friend of mine, can't remember if the machine had this problem before the corrosion got worst, so can't tell if the problem really is a result of this.

Anyway, the corrosion seems to have damaged a section of the board where is the scandoubler circuit only. And the Scandoubler is working fine.

I can upload a photo if it can help.

Thanks again!

[spaceman88]

Hi,
I had an A4000 that was doing that. I replaced the processor board and it worked fine.
Len

[da9000]

@Mugo:

I'm really sorry to hear your situation :-(  I had my A3000 die the same way. It's still dead, and I also fixed tracks and also replaced (actually removed and inserted sockets) the entire 1MB of ChipRAM just in case that was the problem, since green screens CAN be a problem in Chip RAM. But then again, any problem in the address/data lines to Chip RAM and possibly to Buster/Ramsey will yield the same problems...

If you search my previous posts you'll see some relating to this A3000 green death.

One other thing I'd say is to definitely clean all the sockets of the socketed chips, such as the Paula etc. Just making sure. Also any socketed chips should be tested on some other system, again to make sure. I know you've probably done some of this, but just a reminder.

Good luck and do not forget to keep us up to date! Perhaps if you solve your problem it'll help the rest of us in that boat. At some point in the future I will get some time to look into my dead A3000 again. This time I'm gonna X-ray the bizatch to see if there's anything that I've missed.

Cheers

[chiark]

Sounds like we've all been bitten by that ******* battery!  My 3000 died in 1995, and in the last 13 years I've tried repeatedly to repair it all to no avail

Best of luck!

[Mugo]

Hey guys,

Thank you all very much for your replies.
I'll try to sumarize your ideas in this single message.

Regarding the CPU card, this A3000 is stock. No CPU card.
I have an A4000 with a CPPC. But i'm not really inclined to try it on this A3000. Despite all the work it'll render to get the board off the A4000, i don't want to take this kind of risks here.
Unfortunately this is the only CPU card i have available.

As i said before, Paula, Denise and Agnus has been replaced by tested parts. All sockets where cleaned and checked for corrosion. I don't think the problem is bad contact related.

I can only think of some problem still related to the battery corrosion. Or the PALs.

I really want to try and replace the PALs. But i need a provider, as i don't have the equipment to deal with them.

I'm slowly checking all the connectios to the chips and parts that are in the corrosion area.

The problem is that i'm doing this by the schematics, and I don't have them in paper. I only have bad quality scans. It really is difficult (and a turn off too) to check the circuit integrity this way.

If only I could find a hires picture of the board unpopulated, so all the board traces could be seen. This would be a HUGE help.

Thank you all again!

[tone007]

This guy can make you some logic chips.

link

[da9000]

@Mugo:

I'd say: don't bother moving the PPC over. They're fragile and as you say, a pain in the butt.

Sorry I missed the comments on the chip replacement + socket cleanup.

Now for trying different PALs, my suggestion is to talk to Castellen here on A.org. He has reprogrammed them with newer devices that give off less heat and sells them at a good price. They're worth it and he's super (and not a looney like some...). Here are his pages: http://amiga.serveftp.net


As for high quality scans, unfortunately it's very hard to find a total unpopulated board. But if I ever get around to X-Raying the A3000 mobo, you'll have high res scans for free!

Ciao


@chiark:

Ugh... You're in the same boat too? Mine also died a while ago, and so far it's been dead :-/

[Mugo]

Hey Tone007,

Thank you very much for the link.
Will contact Eslapion. Seems that he can provide me exactly what i need!

Regards.

[Mugo]

@da9000:

Thank you very much for all your input and kindness. Very much appreciated!

And sure, i'll be happy to have the xrayed pics, if you ever take them.

Regards.

[da9000]

No problem!

Keep us updated!

[amesie2]

@Mugo

Is the screen bright green or is it more yellowish green? if it is more of a yellowish green it could be the riser board is not seated properly or is shot all together. I have had the same issue you describe when I didn't plug the riser board in.

Best of luck!!

[da9000]

I've only ever gotten full yellow screens without the daughter/riser board.