Time Crisis / Namco System 22 issues

Solder

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I have a Time Crisis boardset (in the 'cage' of course) with a suitable JAMMA adaptor, just having a fiddle with it for the hell of it.

An error is appearing when you go into the:

DSP PCB Test

It's Test 7 which is failing with an error on Point RAM

However, even though the test is for the DSP board, this error ONLY occurs when a certain faulty ROM board is plugged in (ie the board with the many mask ROMs on it).

The fault is showing as assorted corrupt graphics.


I also have another fault on another ROM board - no errors this time, but a lot of the text graphics are slightly doubled up horizontally.

I have an extender cable which allows me to work on the board while it's outside the cage with it running.

Anyone have any experience repairing Namco Sys 22 boards? I'm just dabbling here, it's a new experience working on these and I like an interesting challenge.

It seems strange that there isn't a specific test which will actually identifiy any suspect RAMs and ROMs.

Thanks
 
dsp board with false point ram. i can't tell which, but how about replace one at a time, every ram you found? the ones with SOJ package.
 
The thing is though that the test error and graphics problems don't occur with other ROM boards, just with one of them, ie it's the ROM board at fault and not the DSP. :)
 
If only I could ........... but they are all surface mounted, as are all the other components. Not that I mind SMT work, but it's impractical to do that for every mask ROM if you don't know which one is at fault, and then you have to find a way to read it in a standard EPROM programmer .......

I'm surprised that the self test isn't better given the age of the boardset.
 
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