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xodaraP

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Hi,
I'm currently repairing a Cadash and wanted to start a repair log to keep track of my own progress as well as anyone who might run into a similar issue. Pictures to come later.

A friend sent me a Cadash board he bought, it's working pretty well, except the sprites are a mess.

I booted the board into test mode and straight away was given an object RAM fault

Before I desoldered the RAM (these boards are a nightmare to remove anything from) I checked the F244 and F373 above the object RAM to see what they're doing. Both have the correct signals so the fault isn't here.

I probed the RAM chips and almost all look fine on the scope, but one chip looks slightly different to the others, so I remove it. Sure enough it tests as bad.

I can see some corrosion around the RAM, which might explain why it's died. It also means when I remove it, I lose a couple of traces in the process, which I have to repair. I socket all 4 RAMs and repair a couple of other traces that are damaged.

Now the RAM is socketed, I just need to get replacement RAM of the same type and see where we end up. This is the current status of the repair.
 
Sounds promising. Hopefully the new RAM chips will get it working 100% again.
 
Looks that way, 1 out of 4 is busted, but I've socketed all 4 just for future proofing

If I swap the bad one into other sockets the fault follows but I'm seeing other faults too. Not sure if it's related because the RAMs are on a common bus or if there's further issues
 
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