scrolling problems, k4900 /centipede

tron guy

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I just pm'd mod, but I want to get this out there, because I am out of town trying to get this guy's centipede going.
I will try to explain this as clearly as possible.

I have a centipede that I am installing a working recapped k4900 into.
I will start by saying I have 2 working k4900's with me here at his house.

ONe difference between the 2. One has a vertical adjustment pot installed to the right of the other adjustment pots on the chassis. The other does not have this pot installed, it has a couple of yellow wires, that are sitting on pins and can be moved to other pins.

Ok, the one with the blue adjustment pot, comes up perfectly, the one with the 2 yellow wires that can be moved comes up scrolling.
(neither were scrolling on my hypersports machine when I did testing)
What adjustment should I be making to those yellow wires to make this center, and stop scrolling?
Or something completely different possibly?
I obviously adjusted all the other pots already trying to fix this.
 
I responded to your PM.

The one without the V-LIN pot is most likely an early-version chassis that has to match a specific yoke. if you try to swap chassis', you'll most likely end up with a vertical fold-over that you can't adjust out.

I'm sure you already have the sync connected to the positive sync for Centipede, right? If you are for some reason using a JAMMA board in this cab with a converter, then that's what the problem is.

Otherwise, the hold adjustments should lock it in if it's been rebuilt....
 
I responded to your PM.

The one without the V-LIN pot is most likely an early-version chassis that has to match a specific yoke. if you try to swap chassis', you'll most likely end up with a vertical fold-over that you can't adjust out.

I'm sure you already have the sync connected to the positive sync for Centipede, right? If you are for some reason using a JAMMA board in this cab with a converter, then that's what the problem is.

Otherwise, the hold adjustments should lock it in if it's been rebuilt....

no sync connected to the 3 additional pins. that's where I should start huh?
It does look like a sync issue.
 
The sync for centipede is normally positive separate sync - one for horizontal (P19-pin M) and one for vertical (P19-pin 10).

Now, it DOES have a composite negative sync coming out of P19-pin 12, so if you want, you could try removing the sync from the positive side, and running a jumper from P19-pin 12 to the negative horizontal pin of the K4900 (don't hook up the vertical) to see if it works...
 
all that is beyond me right now. I am working inside the cab and cannot identify anything.

You ahve your 6 color pins, and your 3 sync pins?

Before this wiring harness had a wire hacked out of hte very top 6 color pin wire running to the sync on the old g07. I am trying to recreate that. The thing that bugs me is it works perfectly with no sync wires in the other k4900.

Those yellow wires don't do anything here huh? The ones that are replaced with the blue adjustment pot on the upgraded version. down in the front of the chassis.
 
those are shift jumpers, used to shift the image slightly left or right, or up and down.

And those aren't '6 color pins'. Here is the pinout of that video connector starting at the pin closest to you:

Red
Green
Blue
Ground
Positive Vertical Sync
Positive Horizontal Sync

Ground
Negative Vertical Sync
Negative Horizontal Sync

P19 is the smaller connector on the Centipede board. You should have the same wire color coming out of Pin M and Pin 10 that is connected to the Positive sync pins on the monitor chassis...
 
ok I am getting closer I guess.
Yeah I knew there weren't 6 color pins, but I meant the 6 pin molex. I do understand better now.

right now, there is the 6 pins hooked up.
Should I run a "jumper/hack" from each horizontal and vertical wire on the 6 pin to it's equivalent 3 pin?

that's where I am struggling right now.

another way to put what I am asking:
should I run a horizontal sync 6 pin wire to the equivalent 3 pin spot, same with vertical?
thanks mod
 
No, that won't work.

You said you were able to get this monitor to sync when connected to the other game. Can you get the other monitor to sync when connected to this game? If so, I'd suggest you swap the entire monitors and call it done. It may be more work physically, but it will take less time than all this...
 
No, that won't work.

You said you were able to get this monitor to sync when connected to the other game. Can you get the other monitor to sync when connected to this game? If so, I'd suggest you swap the entire monitors and call it done. It may be more work physically, but it will take less time than all this...

that is the move i am about to make. I am about to pull the tube and chassis out of hte vertical frame and swap it with the horizontal frame. (centipede's stupid vertical screen in a horizontal frame, lol)
yeah if I said it wrong before. I have a monitor that works perfectly sitting on the ground right now, that doesn't fit in the cab. The one that is in the cab doesn't sync. I am about to swap the tube and chassis and be done with it.
I do appreciate the help.
 
for anyone who cares, lol. I changed tubes and chassis' between vertical and horizontal frames that I had and went at it that way.
I will test the monitor that wouldn't sync tonite on my hypersports or gyruss and see if there is still an issue.
 
In case it matters to anyone, I got the monitor home and tested it today.

Fortunately the game I tested it in had 2 different connectors with which I could test.
1 had the colors and positive vertical sync
the other had the colors and pos vert and pos horiz sync both connected.

Anyway, I am stupid and was grasping mod's advice very well last week.

I tried the connection with just positive vertical sync and it worked perfectly.

Again thanks for the help on the fly mod, and she does work. I just wasn't smart enough to do it while I was out of town.
 
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