K4600 - Bad Flyback?

modessitt

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I know this is rare, but I'm not sure where else to look.

Picked up a 4600 with no pic. When I was testing, I was wiggling the daughtercards and applying some pressure to them cause a little arcing between the bottom of the chassis and the metal plate it mounts to.

Anyway, I installed a cap kit, reflowed all solder, checked fuse was good, etc. Put it back in - and nothing. B+ is measuring about 130vdc. No heater glow. No high voltage. There is no heater voltage coming to the neckboard.

It's very rare to see a bad flyback here, but I know it has happened before. I don't know what would give me a B+ so close to good but still cause HV shutdown.

Anyone else have an idea besides the flyback?
 
Check your waveforms on the X-Y card.. Do you have a known good chassis to test it on?Check the voltage right at the HOT..I know it says not to, but..should be in the 1000v range. I had a bad resistor on the X-Y card cause a weak signal to the HOT. Could also be a bad header..

Andrew
 
Already did the headers when I did the cap kit.

I'm going to check the cards in another chassis I have and see if they work okay...
 
check the deflection board on the bottom over by the power board. They will sometimes blow a trace in the power section, and give you that problem. You will need to do some continuity testing in that area to find it usually.
 
Good thought. One more thing to check.

Just don't like having a decent B+ and no heater or HV...
 
I chased my tail for about an hour on one just like that, and I finally found this tiny ass blown trace almost on the left edge of the deflection board.

I would just start checking continuity on the left hand side of the deflection board and I bet you will find the problem.
 
Well, it turned out to be daughtercard-related Plugged them into another working chassis and had the same issue. Diode on the X/Y card was killing my deflection and transistor on the Interface card was keeping all brightness from the tube...
 
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