Weird 6100 spot killer fix

komodo

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Well, after I got a HV cage running (still has jitters I need to find), I decided to try and get a few deflection boards running that I had been working on over the past few months and never could get fixed.

The biggie for me was a deflection board that threw on the spot killer every time. I had been all over the X & Y sections of the board several times. (I think I have about 10 hours on this deflection board alone including all the other issues that needed attention) I was NOT going to give up on it and decided that this was the day. I powered it up and cranked up the intensity on the HV cage to see if there was any picture. To my surprise, there was a complete Tempest image in bright white with white retrace lines connecting everything. (Looking kind of like a spider web)

Hmmm, if I have a good image, then I have good X & Y signals so that isn't throwing on the spot killer. What is? I tested every component in the spot killer circuitry and checked for solder bridges but my work was good. I then figured out the Z-amplifier must not be correct which is why I was getting a bright white image. The spot killer circuitry gets its signals from the big white resistors on the board and then through 2 resistors (R808 and R809 I think- no schematic handy). These were good. Now I am really going bonkers. I then decide to test for continuity from the large resistors throughout the entire spot killer circuit.

Holy schnikies.....no continuity from one of the yoke pins to one of the smaller resistors.(808/809) Viewing the traces on the back side of the deflection board everything appeared to be fine. I could fine no breaks anywhere. Nevertheless, I soldered a small jumper to fix the trace and retested it and deflection board was fixed.

First time I had seen this issue and had to deal with a broken trace in this part of the board. I have seen mangled and missing traces and pads in many deflection boards and hv cages but nothing this innocuous. I'm thrilled to have figured it out and now have it recorded in my repair log.

Thought I would share in case somebody else has a similar issue.
 
This is EXACTLY the same symptoms I have on a 6100 I'm working on....
Every part in the spot killer circuit checks out fine....

Will check to see if I have something similar. Those WG PCBs are }%^*]+>} quality.
An earlier one I worked on had an almost invisible crack near one of the bottle cap connectors..Give me an Amplifone any day....

If this fixes the board I buy you a beer (if we'll ever meet ;)).
 
Alas, I measure normal continuity from the yoke pins to both R808 and R809.... :(

Now I'm really lost....is there a way to temporary disable the spot killer circuit ? Would pulling off the blue/white cable from the deflection board do that trick ?
 
.............and was working on another Wells Gardner deflection board with the exact same issues. Went searching the forums for a solution. Was surprised to find I was the OP on this issue back in 2012. Was even more surprised to find that this was the fix I needed. Going to have to write this into my book of tricks for future use.

Needed to resurrect the thread to remind people how valuable these things are. Please post solutions like this.
 
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.............and was working on a "new" deflection board with the exact same issues. Went searching the forums for a solution. Was surprised to find I was the OP on this issue back in 2012. Was even more surprised to find that this was the fix I needed. Going to have to write this into my book of tricks for future use.

Needed to resurrect the thread to remind people how valuable these things are. Please post solutions like this.

I actually forgot there were blank 6100 deflection boards you could build yourself lol. how do you eliminate the HV jitters?
 
The jitters ended up being bad pots on the Tempest board. This was a Wells Gardner deflection board I was repairing
 
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