MK Vertical Sync

[mr_doles]

I have a WG model 19K7648 monitor (believe it to be a WG7000 by zenith no PXXX number on board) running in a mortal kombat machine.  I am getting a very bad vertical roll and the best tweak I can get gives a good picture and horizontal black bar divding the screen.  The JAMMA connector supplies only composite sync and the monitor has separate pins for horizontal and vertical sync.  The jamma wire is hooked to the Horizontal pin on the monitor, does this monitor require a separate vertical sync as well?

[mr_doles]

Here is a picture of the issue.

[grantspain]

maybe that you need to link the - vert sync to - hor sync
look at this diagram as it shows the pin config
http://www.wellsgardner.com/pdf/Board/K7000_13_19_25_and_27_inch.pdf

i think another option is to link a 5k resistor from - vert sync to video ground on the input plug

[mr_doles]

Think I tracked down the problem.  There was a screw loose holding the chassis to the monitor frame so the board was wiggling slightly.  After we tightened it down that screw it was fine, played for a while with no problems.  Of course when I put the back on and pushed it up against the wall it started to roll again.  I think that the remote board is also loose, but it is a starting point.  Going to tap a few things to see what else may be loose.  I finally got around to putting wheels on this thing so that will reduce vibrations when moving it.

[grantspain]

you should check for bad solder joints on the chassis and the remote board

[mr_doles]

Yeah I just discharged and removed the monitor too look at that.  Here is my next question.  On the board the Horizontal position has 2 wires, 1 red and one black, coming off of it (yellow circle) while the vertical position has only 1 wire coming off of it (red circle).  Is that the way it should be or am I missing a wire?

[grantspain]

that looks ok to me,try adjusting that pot in the left circle as that is the vert 50/60khz pot-it may just do the trick

[venkman]

Think I tracked down the problem.  There was a screw loose holding the chassis to the monitor frame so the board was wiggling slightly. 

that's strange. so you think it was a loose connection, or has it to do with some kind of grounding from teh monitor frame that's affecting it?

[mr_doles]

The v wire definitely needed to be re-soldered, it looked bad, but it did not fix the problem.  So the V should only have the one wire not 2.  I was hoping you would have said, Yup that is your problem.

that looks ok to me,try adjusting that pot in the left circle as that is the vert 50/60khz pot-it may just do the trick

Believe me I have adjusted the heck out of that thing.  It is very sensitive, getting it to stop rolling takes a surgeons hands.

that's strange. so you think it was a loose connection, or has it to do with some kind of grounding from teh monitor frame that's affecting it?

The loose screw did not help but it did not fix it either.  The picture would stabilize then the slightest tap would make it go out of wack.  By tightening the screw it stays stable longer.

I bought this machine from HawkDaddy here and he said the power supply was causing the picture to go out of wack and he would give me a new one when I bought the cab.  He of course forgot it and said that he would send it in the mail but he has not, nor does he return my calls, texts, or emails.  What was happening then the H would go crazy and shutting it off/on would fix it.  You play for a while and the H would go crazy again.  After a while the H stayed crazy (I blam the loose screw and vibrations from playing it not the power supply).  We adjusted the H and the V roll started.  After that we tightened the screw and the H has been fine but I can not get the V back to normal.

[grantspain]

and i guess you have tried another game board,the reason i ask is because millions of years ago when mk was released i remember we had problems locking the vert sync

[mr_doles]

I don't have another game board, this is my first buy.  I do have another 19" monitor that I need to test.  It is a Krystal monitor so I don't know if I can just swap it out plug and play yet.  I have 3 25" monitors that I wish I could use to test this with but I don't have any cords to test them with.
I really hope that the other 19" with work as it is new in the box.

[mr_doles]

S.O.L with the Kristel monitor, looks like it has a very special plug to use it.

[Kevin Mullins]

maybe that you need to link the - vert sync to - hor sync

I was just thinking that too...
A short piece of wire with both ends stripped and shoved into the connector would suffice enough to see helps the rolls.

But I was also thinking that this K7000 probably has never been serviced.
Most likely needs re-capped and cold solder joints checked. (typical stuff)

[mr_doles]

We did resolder the wire from the V Pos on the chassis to the remote board as it was nasty looking.  All other solders looked good.  We linked the -V to the -H but all it did was make the top of the screen all shaky.  After all the soldering and tightening I think that the problem lies in the V Position either on the chassis or the remote board.  The picture seems stable now with just the black bar seen in the second post, it does move up/down a little when the screen changes and during play but it no longer rolls.  On the remote board when you adjust the H Pos it moves the picture far to the left and right, when you adjust the V Pos it barely moves the picture up or down.

Unfortunately my dad is leaving Saturday and he is the electrician who has been doing all the soldering and electrical work.

[Kevin Mullins]

Where are the three wires running to in this pic ?
I've seen them done like that before, but would need to dig through boxes of chassis's to find one like it.

[mr_doles]

These run to the remote board.  There are 2 other wires running there from the chassis as well 1 green and 1 white.