G07 Vertical Collapse - Chassis is rebuilt and works fine on other tube

dochowl

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G07 Vertical Collapse - Chassis is rebuilt and works fine on other tube

So I'm restoring an Astro Blaster which had significant rust/corrosion in the game boards. It has a G07 CBO monitor with no burn. When I picked it up, the monitor was dead. Fast forward a few weeks. I have rebuilt the chassis with new caps, new flyback, new HOT, reflowed connectors and anything that looked sketchy. Add done and the monitor is is vertical collapse. I pull the chassis and test it in another G07 I have and all works as expected. I then pull the working chassis and test it in the Astro Blaster... vertical collapse.

I guess my question is this. Aside from what's on the chassis and neckboard, what else could be causing the vertical collapse? Could this be an issue with the tube itself? Perhaps one of the connections on the yoke is bad? Am I missing something else?

Any input is appreciated.
 
check the fusible resistor at fr401 and the vertical transistors x401 and x402. the ic501 could be bad.

BTW: have you tested the B+
 
Measure the vertical side of the deflection yoke. It is probably open. You could have a broken wire at the connector attached to the yoke, Worst possible case scenario is the winding is actually open. If the boards were rusty very possible the winding wire corroded and broke.
 
Measure the vertical side of the deflection yoke. It is probably open. You could have a broken wire at the connector attached to the yoke, Worst possible case scenario is the winding is actually open. If the boards were rusty very possible the winding wire corroded and broke.

BINGO!!! Unfortunately, the wire at the connector appears fine, so it must be in the winding itself. Time to find a replacement yoke.

Thanks for the assistance.
 
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