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while checking some other stuff, mainly I wanted to see if the two 5600 ohm resistors in the chroma matrix used to drive the green were ok (they were I noticed the 5600 ohm resistor in the grid circuit of the green diff amp was about 50% out so I replace it. while check other stuff I found R702 (6800) was reading over 100k. The odd thing was it was not wired as in the schematic. In the schematic it show it across C and D of the chroma take off transformer T701. In mine its connected from pin 7 of V701a to D with no direct wire from pin 7 to D as shown (which is why it was easy to check in circuit).
I replaced it as well. Turn the set on and there is too much green in the highlights now, so a minor tweek and all good again.
for fun I tried putting a 22meg in P with the ground side of the voltage divider on the shunt, increased about 1kv to 21.5. The overall bias with this setup is about 12v but of course it would change with brightness settings. the schematic shows a 15v (375/390) so its all pretty good.
adding the 22meg in p is within the tolerance level of the resistor so I will just leave it at that.
I don't know what happened but the HV started going up to over 25kv and I could see the shunt was not glowing green suddenly. I tried wiggling the tube and even a new tube, still not regulating. finally I pulled the chassis and check the filaments for voltage, all the resistors, put it all back in the cabinet and now its working again, I have no idea what was going on with that.
I am going to try changing the voltage divider resistor to 120k vs 83k (as done in later production runs) just to see if there is any effect on the cathode current in HO tube (the voltage divider resistor is on the horz osc board).
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