wg 6100 deflection board troubleshooting

wsharp

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I have a WG 6100 monitor that I'm working on getting working. With known good chassis transistors, I have a deflection board generating results only in the upper right quadrant of a horizontal monitor. Negative x + y are out. Is it possible to test a deflection board outside the monitor with just the power transistors and power inputs hooked up? I'm interested in comparing the voltages in the manual at various test points vs. what my board is producing.

Or do I need all transistors connected to get comparison voltages? I assume I can leave the HV disconnected for doing the testing?

I have tested switching the power transistor and deflection transistor plug (P600 and P700?) and still don't get any negative deflection so I'm assuming the problem in on the deflection board itself. There is some burn damage on the board in the deflection part that has been previous repaired.
 
Yes, thanks. I have read that PDF and it does not answer my questions.
 
Well, you can test the low voltage section without the deflection transistors or HV hooked up, but you can't test the deflection voltages without the transistors.

The 6100 is fairly easy to troubleshoot. Is your deflection board a P314, P327, or one of the others? If a P314, does it have the input protection board mounted on the back?

One thing about the deflection transistors (besides being good and having insulators and making sure there is no continuity between the outer casing and the frame of the monitor) is that sometimes the wires to the sockets break off or are barely hanging on, so make sure they are fine. And that there is no cold solder on the pins that the connectors plug into.

Now, you say you only have a picture in one quadrant. Is it a perfect pic, or is it distorted?

As far as the burn marks, I'm assuming they are near a diode or resistor close to either Q603 or Q703? Are those four transistors (and accompanying diodes and resistors) okay? What about the Q600/601/602 and Q700/701/702 transistors? Fuses okay? Your +/-28vdc good?

I find it much easier to fix them then to talk someone else thru it.

And this is assuming that your game pcb is outputting the signal properly. What game is this in anyway...
 
Thanks for the reply. I worked my way through the board and managed to fix it. I had a bad MPSU57 that I swapped out and a cracked resistor connection for one of the large cement resistors on the deflection board.

I was getting HV so I assumed the power was okay but instead of -25.5 I was getting -33 out of the power transistor. HV didn't mind that but I think that was the cause of both of my negative quadrants not displaying. Once that was fixed and the other two problems, I have a full picture now with a ZVG.

Now I just need to track down a horizontal Atari vector cab to put a multi-vector ZVG set up into. I'm in Allentown, PA if anyone has a cabinet nearby.
 
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