Fun with WG6100 deflection board - a little help needed please?

MadocOwain

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Fun with WG6100 deflection board - a little help needed please?

Many moons ago, I bought a Tempest. Turned it on, it displayed vectors for a minute, then POOF, magic smoke. I turned it off, bought another 6100 and kept the smoked one as "just in case". I recently bought a Gravitar without a monitor, so remembering this old Tempest monitor, I pulled it out to see what was what.

Immediately, I noticed the resistor at R101 was SMOKED. I'd heard of this "LV2000" product that replaced the troublesome low voltage section, so I got it and put it on.. screwed up the holes for the standoffs though but eventually got it figured out.

I have a known-good 6100 chassis/tube/neckboard/HV/harness/game board, the only thing I'm testing that is bad is the deflection board. It's a P314 with no mods except the LV2000. I get correct voltage on all pins of P100. When I turn on the game, the spot killer light comes on, I hear vector chatter but no picture. Turning the brightness up does show I have both X+Y. I've removed the solder and re-applied for each header pin and tested continuity for those as well as for the 15-pin connector. My fuses test good at the holders.

At this point, I am about to order the Bob Roberts "super-mondo-deluxe" kit including replacements for Q603/604/703/704 and some resistors, to apply to the deflection board. Is there anything else I can do to trace this issue without shot-gunning? Can I disable the spot-killer to enable the full deflection output(is that even a thing?). Does anyone do repairs for these boards, in case I do have to shotgun and that fails?

Thanks!
 
If you have both x and y when you turn brightness up, then Id bet there is a fault in the spot killer. Check all the transistors in that section.
 
If you have both x and y when you turn brightness up, then Id bet there is a fault in the spot killer. Check all the transistors in that section.

2nd that... or the resitors in the path
R809/808
If you check the bases of Q801 and Q802 you should be able to see which one is on.
 
The -3906 from Q800 (PNP) - measuring out of circuit using diode mode on the DMM, everything tests out at about .6-.7. Same for the two -3904s from Q801-802 (NPN). I haven't messed with the resistors, but neither look burnt. Hopefully replacements come with Bob's kit.
 
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