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stelio54

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Hi all,

I have a 6 in 1 Jamma switcher with MK1, MK2, and NBA Jam all successfully installed. I recently bought a Bad Dudes board from a reputable source, citing it as “working.” The board is in fantastic cosmetic condition, and after a close review doesn’t have any burnt traces or components that I can see.

When I insert the board and fire it up, no picture, no sound, just some weird occasional noises.

It makes me wonder if there is something about my set-up that needs adjusted. I’m not an expert at this stuff yet. Any assistance would be greatly appreciated.

Steve
 
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Probably wise to check voltages with a multimeter, the +5V line is the main one you're interested in and removing the jamma switcher from the chain to rule it out as a point of fault.
 
Thanks frank. I’ve moved the other “working” boards around the switcher to test all the slots and everything seems to check out in that regard.

As far as voltage checking goes, do you have any advice as to how to check that on a switcher? Do I put the board in the switcher, Activate the board and check the voltage somewhere on the board?

If I find the voltage is off, how would I adjust that? I do not believe the switcher has the ability to adjust voltage on a slot by slot basis.
 
Can you test the B Dudes board sans the switcher?
 
I could probably just disconnect the switcher and plug the board directly into the harness. I will try that when I get home tonight. Thank you.
 
That would be the best way to start.

When diagnosing a possible fault it's best to eliminate as many potential points of failure as possible.

What type of power supply are you using?

When you check the 5V level, use a multimeter and probe from the jamma pins on the game board end.
 
I've tried today a Bad dudes original board and I'd say the sync signal is not very close to the standard because my TV has some difficulties offering a fully stable image and it appears noticeably shifted to the left. To make it work I need to bump the sync signal to ~750mV, I suppose the Martin Jones Sync Pulse Generator is what I need.

Not sure if this has to do with your problem, but this game uses the -5V line. As Frank said you should check the voltages at the jamma edge and check there is at least 5.00V at the +5V line. This board is big and if your PSU is not very good or it's not correctly set up it may produce enough voltage drop to make the board don't work.
 
MK1, MK2 and NBA Jam all use -5 and are much more sensitive to voltage than Bad Dudes would be.

Try the Bad Dudes without the switcher and go from there
 
When you test from the jamma edge with the actual game running (not a boot screen or anything, like actually running) using a fluke multimeter, should one strive for exactly 5.00v?
 
I think 4.95V - 5.05V should work. I've run similar boards with 4.93V at jamma edge, but take into account that it may be some voltage drop across the board depending on how good it's built.

Ideally you should get 5.00V at both the jamma edge and at Vcc of the farthest IC.
 
While you are at it, check the interconnect between the 2 boards.
 
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