Vertical Rolling on LCD.

[Witchboard]

I've searched for vertical rolling and found several threads, but I figured I would post a new one considering I'm kind of going backwards compared to most.  I got a PSOne LCD that I'm using in a JAMMA test rig and I'm getting some vertical scrolling on it.  I've checked the voltage on the sync line and it's a little over 5 volts DC.  Do you think putting a trim-pot in the sync line might help resolve this?  is a link to an example video I shot.

[grantspain]

don't look like a sinc issue to me,its just vertical hold,but you could try link hor/vert sinc if you have those on the lcd input

[Silver]

Have you hooked up any other shources to the LCD - do they work?

I don't think you should be reading 5V DC on the sync line. The sync lines are pulses of voltage (could be -ve or +ve) that you can't really read without a tv signals reader or a waveform monitor. So taking a DC voltage is just going to give you a DC Bias on that line - which is not the sync voltage.

[Witchboard]

don't look like a sinc issue to me,its just vertical hold,but you could try link hor/vert sinc if you have those on the lcd input

According to the instructions I used to hook up the LCD it has composite sync input.  It was meant to hook up from VGA, but I just used the RGB, Ground and Sync wires.  I didn't use the PCB, but cut the wires and solered them directly to a 10 pin connector.  I didn't see any other components on the board.

Have you hooked up any other shources to the LCD - do they work?

No, I haven't tried any other sources, and it may no longer be an option since I've cut the wires, but I'll see what I can do.

I don't think you should be reading 5V DC on the sync line. The sync lines are pulses of voltage (could be -ve or +ve) that you can't really read without a tv signals reader or a waveform monitor. So taking a DC voltage is just going to give you a DC Bias on that line - which is not the sync voltage.

You're talking above my head.  I just checked the voltage of the sync line coming from my JAMMA harness.  I'll take your word on everything else.

[grantspain]

its possible your sinc input may need a different common,but if you have followed the instructions to the letter then it should be o.k,only other thing i can think of is did you use shielded cable.surely that screen must have some kind of vert hold pot though

[Kevin Mullins]

This is the most common setup I have found for this .....
http://www.arcadecollecting.com/info/sonylcd.jpg
I haven't done one myself yet, so I'm not exactly sure what all is on that little pcb.
But it looks pretty straight forward.

Have you tried any other jamma game pcb's with the setup you have now?

[Witchboard]

its possible your sinc input may need a different common,but if you have followed the instructions to the letter then it should be o.k,only other thing i can think of is did you use shielded cable.surely that screen must have some kind of vert hold pot though

I haven't found a vert hold pot anywhere on the board.  I'll unmount it and double check though.  I'm not sure what you mean by shielded cable.  I'm using my Neo-Geo for the test signal straight from the JAMMA harness and I haven't added any extra cable to the PSOne harness so it's all the same cable as before. 

This is the most common setup I have found for this .....
http://www.arcadecollecting.com/info/sonylcd.jpg
I haven't done one myself yet, so I'm not exactly sure what all is on that little pcb.
But it looks pretty straight forward.

Have you tried any other jamma game pcb's with the setup you have now?

I have pretty much that same thing, but I looked at the board in the picture and didn't see any components on the board, so I just traced out the wires with an ohm-meter and cut them then directly soldered them to a connector for the monitor.  I haven't tried another game PCB to test.  I'll try that next.  Thanks.

[Witchboard]

I used a different board with a different JAMMA harness and everything seems well.  I guess my Neo-Geo has an oddball signal or something.

[Kevin Mullins]

I vaguely remember something about the Neo-Geo boards doing that to certain monitors and such. But can't think of the details for the life of me. Weaker signal than usual or something maybe.

Glad it's up and running good now though.

[Witchboard]

Me too.  Thanks for the help everybody.