cab and game 5 v problem

newlands1

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have two jamma cabs tryed the same game in the two cabs. and one is ok with the game but other is not






cab (1) this is the one the game is ok . test the 5.v on the jamma conector and it says 5.12. and on the game board at the jamma fingers it reads 5.12. as i say game plays ok on this





cab (2) this one the game problems r screen pulls sightly down at parts.and u can see like 3 pencil lines one the screen. test the 5.v on the jamma conector and it says 5.20. and on game board at the jamma fingers it reads 4.90. ... any ideas guys . i have swaped with a other psu unit and everthings is the same
 
and it says 5.20 and on game board at the jamma fingers it reads 4.90

4.9 should be enough to boot the game but then again maybe it's not

looks like you have a voltage drop through the connector which may indicate a weak pin inside the connector not allowing proper electron flow

might have to re-pin the connector
 
4.9 should be enough to boot the game but then again maybe it's not

looks like you have a voltage drop through the connector which may indicate a weak pin inside the connector not allowing proper electron flow

might have to re-pin the connector

This is where you want to start. You may get away with cleaning the connector with an eraser. Either way it is most likley the connector.

Also check your voltage at diffrent points on the board. Sometimes the voltages will drop further away from the connector. It is not uncommon for techs. to add wires to other parts of the boards to get proper voltage to entire board.
 
when mean the connector r u on about the the jamma connector. or the the fingers on the game board.sorry guy just to ask as am still new to this.thanks for ure tips .
 
the connector is in the JAMMA harness (the black plastic piece)

the finger is the contact that the connector connects to at the game board's JAMMA edge.

I swore I posted on this same topic yesterday, but maybe I didn't I guess lol. if your board works in one cab and not the other, I would suspect that the JAMMA harness is bad on the "bad" cab".

if you're metering 5.20 at the back side of the JAMMA pin, and it's 4.90 at the board, then you're probably looking at a dirty or bent pin in the JAMMA harness. I'd say to properly correct this, you'll have to replace the JAMMA harness, which I know isn't the coolest thing to do since you have all those wires to reconnect, but it's either that or play around with replacing those pins until you get it right.

I was lucky that the only 2 JAMMA harnesses I had to replace were from Midway cabs and I had exact Midway copies of them that I could just plug most of the stuff back in lol

in case you didn't know, there's the plastic key inside the JAMMA harness, the smaller part of the harness for about 6 pins is where all the power supply connections go to (which you should be focusing on), I would check all the pins inside there. if there's dust or corrosion or other shit you might be able to get away with contact cleaner and an old toothbrush... not sure if there's a sanding device you can fit in there or not.

that's my suggestion, anyway.
 
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