Amiga 2000 - a2091 memory issues

[torradan]

I've been looking around for over a month now, and I'm at a loss.

Have a 2000 with a Fusion Forty, and a 2091 controller with 2MB of RAM. It was working great, and it started acting strange (sometimes it would noty to workbench, sometimes it would just sit doing nothing), and finally wouldn't boot at all.

Removed all cards and get to kickstart screen.
Reinstalled Fusion Forty, I get to kickstart.

Put a2091, it gives me the FF splash screen, and goes to a black screen.

Removed FF and still won't boot.

Now, if I disable the ram on the a2091, it boots no problem. Also tried another card, and same scenario. Swapped memory, only allowed 512k (or 1MB), and still won't boot. I checked for battery damage, replaced 68k socket because it was destroyed (battery was removed before I got it, but it was never cleaned up), and toned all the traces around the affected area.

Both 2091s work in another machine, and both have latest ROMs.

I tried diagrom, and it recognizes the 2mb, but when I try to test the memory it locks the machine up solid. C-A-A doesn't even work.

Any ideas? I think I covered all the bases, and I really don't know where else to look.

Thanks for any help. I can't afford to lose any more hair.

[SpeedGeek]

First, disable or remove the Fusion Forty and check your A2091 RAM with the stock 68000.

The A2091 install disk has a RAM test program but any good RAM test program should work also.

TIP1: Commodore used "Cheap" DIP sockets on the A2091 so it's always a good idea to re-seat the RAM chips and the RAM controller.

TIP2: The FF draws very high current from the +5 Volt rail, so an aging PSU could be struggling to maintain the +5V supply. So, use a DVM to check the voltage here also.

P.S. After reading your post again, you mention PCB trace damage near the 68000 socket. So, I suggest checking and re-checking the continuity of any questionable areas.

[torradan]

Hey, thanks for the reply! I just tried all of that (test continuity, tested with brand new 300w PS, reseated ram). Tested every pin for 68k - they all go somewhere. The battery infection wasn't really bad, it just attacked the socket and CPU legs, but both were replaced.

FF removed again, and didn't help.

Can't test the ram with the disk because it won't get that far when ram is enabled. Pretty much power led is on, and keyboard caps led blinks once, and there it sits.

The scsi card doesn't even blink the hd led with ram enabled. Same results with both cards. I'm not sure if that bit of info would help, forgot to include in my original post.