A501 Rev 6 no memory detected

General hardware issues and troubleshooting etc

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insanity213
Posts: 5
Joined: Tue Aug 11, 2020 6:23 pm

A501 Rev 6 no memory detected

Post by insanity213 » Wed Sep 09, 2020 2:54 am

So I dug out an old A501 that I've had for years. I removed the leaky battery and the damage wasn't extensive at all. The RTC shows up but none of the RAM is being found. Amiga Test Kit 1.11 Memory diagnostics says "WARNING: Possible faulty SLOW RAM detected" and allows me to force a test. Every bank fails on the 1st test.

I've checked all the caps and resistors on the board and everything checks out. I removed the RAM chips, installed sockets and new chips but still no dice. I can't find a schematic, so I'm pretty much out of gas. Any idea what would cause all of the memory to not show up at all?

cmorley
Posts: 159
Joined: Tue May 28, 2019 5:46 pm

Re: A501 Rev 6 no memory detected

Post by cmorley » Wed Sep 09, 2020 7:11 am

Thw A501 schematic is in the back of the schematics for the A500. It's called "Cake" or something like that.

insanity213
Posts: 5
Joined: Tue Aug 11, 2020 6:23 pm

Re: A501 Rev 6 no memory detected

Post by insanity213 » Fri Sep 18, 2020 12:32 am

Thanks for the tip, who ever reads the last page of a manual?

Anyway, I still can't figure out whats wrong with this thing. I broke down and bought a new memory expansion from AmigaKit.

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GadgetUK164
Posts: 176
Joined: Fri Jan 04, 2019 2:26 pm

Re: A501 Rev 6 no memory detected

Post by GadgetUK164 » Fri Sep 18, 2020 11:37 am

If one bit is bad in one of the DRAM chips, it will register as none. If you use DiagROM or Logica, those should tell you which bit is at fault, you can then target the specific DRAM chip.
My YouTube Channel - www.youtube.com/GadgetUK164

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