6100 Burning Out Flybacks

jimk

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I have a 6100 that is giving me nothing but headaches. Counting the flyback it had originally, it has killed 3. The brand new one I just put in lasted about 20 seconds before the HV probe went from 15KV to zero. (I didn't get a chance to adjust the HV)

I'm 99% sure the problem is in the HV board. I've tried all the other parts in the other Tempest sitting next to it including power sources; they all work fine except the HV section. The HV board has had a full cap kit and all the transitors, diodes and resistors check out fine.

Any idea on what could be killing these flybacks?
 
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I guess it could be bad luck. The second flyback was used, I thought it powered up but I'm not 100% sure. The new one I know for sure was working for a few seconds.
 
No I didn't but the high voltage probe read 15k volts when the flyback died. I was going to give it a couple of minutes before adjusting.
 
It's also possible that your aren't killing the flybacks at all. It sounds like your HV shutdown circuit is kicking in due to a problem elsewhere. Replace the HV adjustment pot first, and check the ZD902 (not to be confused with D902).

If you're not seeing catastrophic failure (like sparks or smoke), then I would suspect the flybacks aren't failing. Get a ring tester on them to be sure.

I've worked on other models (like the G07 and K700) where you'd get a very tiny burst of HV when you turn it on, then it drops to zero due to a problem elsewhere in the chassis causing the HV to shutdown. This is done to protect the more important parts like the flyback, yoke, tube, etc...
 
It should be obvious if it's the over protection circuit. The led will be on. I think only some 6100's have it. There will be an adjustment pot for it near the front edge of the hv board.
But at 15k I would be surprised it would be kicking in.
 
It appears it is going into HV shutdown. The probe shows voltage for a second before dropping to zero. If I turn it off and on again I get nothing, it's got to sit for awhile before the HV will return for a second on power up.

I've replaced R918 and ZD902 and it's still shutting down. I've also checked all the transistors and they appear fine. Is there a component I should be focusing on?

It's a P316 board version.

Thanks
 
It should be obvious if it's the over protection circuit. The led will be on. I think only some 6100's have it. There will be an adjustment pot for it near the front edge of the hv board.
But at 15k I would be surprised it would be kicking in.

Not all HV shutdown problems with a 6100 cause the spotkiller to light....
 
Have you completed the procedure for adjusting the HV and high voltage protection circuit in the manual yet?

High voltage pot and high voltage protection pot fully counter clockwise.
Turn game on, let warm up 5 minutes or so
Adjust high voltage pot to 22.5kV
Turn high voltage protection pot clockwise (slowly) until high voltage drops to zero.
Turn game off
Turn high voltage pot back counter clockwise (roughly center should be good).
Turn game on.
Adjust high voltage pot for 19.5kV.

Does your HV PCB have the overvoltage protection pot. Can't remember if the P316 does.
 
This issue turned out to be a bad connection the bu207 transistor mounted to the HV cage.

Thanks for the help.
 
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