Galaga video issue (video - ooooh exciting)

How's your sync hooked up? Was the chassis checked to make sure the sync resistors were the right 390-ohm ones? Does adjusting the horizontal freq change the speed?

And try disconnecting the big edge connector and just leaving the 2 molex connectors on. It will power up and show video, but you won't be able to play it. Still, sometimes it will work like that but not with the edge connector on, indicating a problem with the board...
 
No. Should have the sync connected to both the negative vertical and negative horizontal sync pins.

If you have, you might try moving the ground wire from the 6-pin connector to the 3-pin connector.

And there might be a cold solder joint on those sync pins. Very common...
 
Same results with 3 known working chassis. Now I think I have it hooked up wrong, mainly because I don't follow what you're suggesting. Can you elaborate to help a moron understand?
 
You should have a 6-pin connector on one side of the Galaga boards. That is the video signal out.

On the monitor chassis, there are two video connectors - a 6-pin connector and a 3-pin connector. Looking at the chassis from the back of the monitor, the connectors are on the middle-back-left. They are numbered as follows:

3-2-1
6-5-4-3-2-1

For the 6-pin connector on a Galaga:

1-Red
2-Green
3-Blue
4-ground
5-not used
6-not used

For the 3-pin connector on Galaga:

1-not used
2-sync (vertical)
3-sync (horizontal)

Galaga uses composite negative sync, so the same sync wire goes to both sync pins. if it doesn't, then the image will roll and you won't be able to stop it.

A lot of time, the solder on the bottom of the chassis for those pins will come loose from the pins. Reflowing it with a soldering iron should fix it, although you may need to add a touch of solder.

Also, sometimes a problem in the ground circuit to the sync circuit can cause a problem, and moving the ground wire from pin 4 of the 6-pin connector to pin 1 of the 3-pin connector will fix it.

And there was a mistake in the manufacturing of some G07 chassis that put the wrong resistors at R314 and R317 in the sync circuit. They should be 390-ohm resistors, but some chassis' had 4.7k-ohm resistors. if you have the wrong ones, it won't sync....
 
No gold. 3 different, known working chassis, tried moving the ground like you suggested, even left the 3 pin connector off, same results. Also rechecked power supply voltage. Still plays blind, but both syncs seem to be non working. Try a different monitor maybe?
 
Confirmed not the chassis by putting it in my pac cocktail. Looked gorgeous. Can the monitor be the culprit here? I have another g07 in an old moon patrol...
 
You have the video cable hooked up incorrectly. Let's see some pics of the video wiring from the boardset to the monitor. The more detailed the better.
 
The video cable is wired wrong.

The sync connection is wrong on the monitor end.

The video cable has 2 ground wires going to the exact same location on both ends.

Remove 1 of the 2 sync wires from both ends of the cable, the jumper the other sync wire at the chassis end.
 
I'm glad you're spotting what's wrong. I need just a little more detail.

There are 2 wires that go from pin 4 on the Galaga board (sync) to pins 2 and 3 on the chassis-side sync connector (using mod's description below), and there are 2 wires for ground that go from pin 5 on the Galaga board to the ground pin (#4) on the 6 pin connector on the chassis side, making the 2 ground wires redundant.

What am I supposed to pull and jumper?
 
The ground is not causing the problem so leave it alone.

Pick 1 of the 2 sync wires and remove it from the 3 position connector. Jumper the remaining wire to the 3 position connector where you removed the other wire.
 
Yep that's electrically the same. Pin 4 (sync) on the board-side of the plug has 2 wires coming out of it that go to pins 2 and 3 on the chassis-side sync connector. I tested with my multi-meter to be sure. If I pull one of the 2 wires from the chassis-side sync connector, tape it back, then take the remaining wire and jumper it to where the other wire was just pulled from, isn't that accomplishing the same thing?

It's late so I might be getting loopy.
 
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