Help with odd WG6100 vector issue

Hello gang. I've been rebuilding some K6100 monitors lately and have run into a problem. Here's the scenario:

I have two K6100's on hand. One is in a Black Widow cabinet and works beautifully as does the game PCB itself.

On the workbench is the other K6100 which is close enough to the cabinet that I can hook it up to the game for testing. This monitor needed work on both the deflection PCB and the HV cage so I picked the latter to start with. I basically installed a "rebuild kit" from Bob Roberts and checked the two chassis mounted transistors. To test my work I took the working deflection board from the first monitor, installed into the second monitor, hooked up to the game and, presto, a working monitor. With a "but...". See the pictures at the link below but basically vectors near the top of the screen have little wiggles in them.

http://gallery.mac.com/doughill303#100025

So, since I had the HV working but not perfect I figured I'd install the rest of the "rebuild kit" on the deflection board while I had the soldering iron hot. With that done I switched deflection boards, checked the six chassis mounted transistors, etc. and fired it up. No spot killer - good. But, hey, the little wiggles are gone too! Ok, so I put the other deflection board back into the cabinet and fire it up. No wiggles there either.

I had thought the problems would have followed one of the boards but it doesn't seem to have done that. If switch the deflection boards again the wiggles come back [to the second monitor]. So, my question gentle folk, is what the heck is going on? Obviously the power supply and game PCB are the same in both tests.

Any ideas? One thing to note is that the wiggles only appear towards the top half of the screen. Vectors [text and the spider, etc.] near the bottom are normal.

-doug

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Received on Fri Sep 14 22:10:33 2007