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DaveR

Student
Joined
Aug 16, 2019
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Location
Devon, UK
Hello all
I know that there is a active topic at the moment with multi's and so on, I purchased a 641a MCU kit of Caius who I beleive is active here about month ago, I thought it would be useful.

I have TWO Pac-Mania boards, I purchased a second one recently as I needed a good working one to attempt repair with, but I am struggling a little and now need to reach out for some top tips due to amateur skills.

My problem is, the boot is black screen, nothing, the 6809 CPU at W6 (and others) seems to do a few things and then does a loop, nothing much happens as i probe the address lines on the CPU. I have no game sound, zilch.

1: Swap CPU boards, the problem lies on the CPU board.
2: Swap all socket'd chips between CPU boards, this does not fix the problem.
3: No shorts
4: The 3 processor chips do get warm
5: I can't see any broken traces yet, Cus117 seems to measure okay for continuity.
6: I have seen some floats around D3, E3 and replaced the D3 74LS173 but I think that I should be looking at CPU pages right now.
7: Using Probe, the board seems active, but in a repeative loop.
8: Test Switch / makes no differnce.
9: Done some soldering around an edge connector.
10: Processor reset/halt lines good

My theory is, the rest of the chips should give error messages and not black screen, so I am thinking memory, W-U5. 117, U6, S6 ETC.

If I boot with sound, the GOOD board will make the speaker click - click - click - click then start.. then BAD board, clicks just the once after a second after boot.

I am thinking about swapping the 117 but concerned I might over heat it with hot-air, trying to do as much with easy to replace chips before I try that custom.

Any top tips please?
 
@DaveR
I’m in the exact situation as you with one of my Namco System 1 CPU boards.

Did you resolve your issue?
 
Well I ended up messing up the second set by removing the 117 and swapping it, might have been too hot .. i don't know.

So at the moment the boards got swapped out at the arcade I work at as they had a broken IO and I had a working IO (bottom board) and a good cpu board, it is now Splatterhouse. The other boards are their somewhere, not touched it since.
 
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