NBA JAM: T.E.

[battletoads]

Hey I just got a NBA Jam Tournament Edition PCB off of EBay, complete with the sound card and sound pot.  I hooked it all up and swtiched it on, and the screen sort of jumps, moving down past the bottom of the monitor and then coming from the top again.  I can see the game do a rom test, and every rom works fine. 

Im honestly stumped as to what could be doing this, if you check ym apst posts youll see that im working with a Jamma cabinet that worked fine with TMNT, X-men, and Battletoads.  Maybe this is a video or power issue?  I disconnected the sound card and the problem is still occuring.  It reminds me of when you try to play a PAL dvd player on a NTSC tv the way the image jumps, however there is no color distortion.

I know that there is no +5 or -5 or whatever wire running from my Jamma harness to my power source, could that be the problem?  Thanks, I appreciate it.

[RayB]

You're funny.  Adjust your V-Hold knob.

[battletoads]

OK.  Well after looking up exactly what that is, ill have to take a look at the monitor, because my CP is custom and defiently wont have a knob on it.  This was originally a Gauntlet 2 cabinet.  Should the knob be on the monitor or one of the PCBs?  Thanks man.

[srabelpawz]

  the knob will be on the monitor board or a remote board coming from the monitor. i suggest you read up on monitors a little bit before reaching your hand in there because it will have to be on in order to adjust it. BTW the monitors have a charge that could make you pee yourself

[battletoads]

hmm ok.  do you have a guide on handling monitors, like gloves to wear or precautions to take?  I have the build your own arcade book but i dont remember it being discussed in depth in there. 

I guess turning this knob will change the monitor to a frequency that supports this individual pcb or something, because 3 other games operated just fine.  Thanks

[srabelpawz]

  you should be o.k. as long as you stay away from the anode (the suction cup on the monitor) as far as the knobs go you can turn them without being shocked.

[battletoads]

Ok cool.  Yeah I got juiced a few times putting quarters in the one slot, because the plastic part of the mechanism is gone.  Way i see it that wasnt that powerful, the monitor is probly a lot of voltage.  Ill give it a try when i stop by my house monday and let you guys know i turned out

[RayB]

Ok cool.

[battletoads]

Hey anybody know for sure where Im gonna find a v-hold knob on a Gauntlet 2 cabinet?  I know theres a panel on the lower back of the cabinet that comes off, but im not sure about a removable panel near the monitor.  I found a manual and schematic manual for Gauntlet 1, which appears to be very smilar to the 2nd one.

This page has the manuals.
http://www.crazykong.com/manuals/page3.html

This seems like it should be a very simply problem to fix.  Also, my -5v wire is NOT connected to the power source, I attached  picture of this.  If I were to conenct the -5v to the power source, could it damage anything?  I worry that the previous owner might have it disconnected for a reason.

[tommy]

I change jamma boards often on my cab and as said.. most times you will have to adjust the monitor when you change boards.

If you change from a capcom board to a midway board you will have to recenter the monitor, rarely will you have to adjust the v-hold though from my experience.

V-hold should be marked on the pot on your monitor.

The -5 makes some games look like it's a monitor problem if not hooked up.. while others do not need it to be connected. I do not recall if that Midway board needs it to be connected, i know NFL BLITZ does otherwise to an unfamilar gamer it would seem like there is a monitor problem.

[RayB]

V-hold is always a knob or surface mount potentiometer somewhere on the monitor circuit boards. THere's no removable panels. Not sure what youre talking about there.

[battletoads]

Alright cool.  I shouldn't have a problem finding the v-hold knob then.  What I meant by the removable panel is that there is a removable section of the arcade cabinet's back (a board that screws out, and at one time was held on by locks).  When I pop this out, I have access to the inside of the cabinet.  I'm out at school till monday so I cant check for sure, but I believe there is no section of wood directly behind the monitor that pops out, and im not sure I can access the back of the monitor (where I suppose the vhold knob is) from the main removable panel which is lower down on the back of the cabinet. 

If you check out page 7 of this guide:
http://www.crazykong.com/manuals/Gauntlet.man.pdf

You can sort of see what I mean.  The reason I mention the -5v wire so often is that i'm new to owning an arcade game, and I dont want to hook up a wire if it's going to fry anything.  I built my own C.P. this summer, but that was pretty straight forward.