User avatar
wi11ypig

Posted Sun Jun 16, 2019 3:46 pm

Hi all,

I've been trying to get an A2000 working. I have a working 500 and have swapped out all the 'swap-able' chips. They all work fine in the A500 but the 500 chips make no difference in the 2000.

I bought a diagrom chip from Finland and with it installed, I get output to the screen and serial, but the machine hangs soon after and won't work at all until I allow the machine to sit off for a while (I don't want to use the term 'cooldown' because none of the chips actually get warm.)

Any hints for troubleshoooting? The caps all 'look' fine and the battery leakage was minimal and cosmetic. (Plus, I've tested continuity from the CPU and rom chips and all is fine.

I'd appreciate any advice to go forward from here!

-Keith

User avatar
obitus1990
USA

Posted Sun Jun 16, 2019 5:55 pm

There's probably more damage from the leakage than you think. Unless you start removing sockets and checking the traces underneath them, you might not find it. Broken traces, damaged vias, etc.... And checking continuity between just those chips isn't likely enough. Don't rely on just single point tests. Use the schematics and test points along the same circuit path, but, further out from the "origin" point, not just the first point away from your "origin."

I wouldn't even be thinking of caps causing the issue yet. That's more in the realm of the SMD boards.

Good luck!

User avatar
Mr.Toast
Roseville, CA

Posted Mon Jun 17, 2019 4:37 pm

Post some pics so we can get an idea what is going on (as well as what revision board we're talking about).

Like @obitus1990 said, there is often lurking damage hiding under sockets and, if so, is probably still chemically active with corrosion processes. I was pretty disappointed with some of the online schematics for the A2000 as they often span multiple pages of PDFs. It does make it hard when trying to troubleshoot. However, once you see the relationships between some of the major ICs, it does become easier to do point to point testing.

User avatar
obitus1990
USA

Posted Mon Jun 17, 2019 4:54 pm

Yes, you’re right about the 2000 schematics, Toast...they suck since they’re all hand drawn and were poorly scanned into PDFs. Almost illegible in some areas, and, hard to tell which revision board. I did find one that was at least searchable PDF form, but it’s of limited use since all the diagrams are hand notated.





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