Amplifone Deflection PCB - Spot Killer "ON"

jetusenet

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Amplifone Deflection PCB - Spot Killer "ON"

Hi;
I rebuilt an Amplifone deflection PCB as I always do but this one did not come through like the others.

I have it in my Star Wars that I am building and I get deflection chatter but the spot killer is on as well.

I tested and got voltage on the X and Y outputs - just to make sure I swapped it with a known good working deflection PCB and the game has a nice display. I put this one back in and "spot killer on".

I tested the transistors again just to make sure and they all seem to be OK.

I don't understand why I would have deflection chatter and still have the spot killer on.

Is there something with this situation that rings a bell to someone?

Any hints would be greatly appreciated.

Thanks
Jeff
 
OK, I started to do comparisons with the known good and the defective
deflective.

I found a discrepancy between the Q12 transistors. Traced it to R31
which reads 3.3ohm on the good and 1.54Mohms on the bad.

I think I found the problem. I'll swap it out and post the results.

Jeff
 
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