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#64
11-03-2014, 05:26 PM
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ok here are some voltages, i hope im right with the wires here. ok the yellow with colors is cathode,blue 280.9v green 276.8 red 245.3. g2 white with colors, drives maxed red 760v blue 757v green759v. g1 solid colors red 195.7v blue 186v green 193.6 . with the set on warmed up bright down hv adjust maxed cant get no more the 23kv it does vary via the adjustment so its working but something is wrong in the circuit. i also tried pulling the crt plug off no change in hv. however i didnt yet pull the 6bk4 cap off to see if the hv goes up the last time i pulled the cap off it did go up much more. i also checked the ohms again on the hv adjust pot and its good. so i guess the boost voltage is there as it shows on the maxed drives.
Last edited by timmy; 11-03-2014 at 05:30 PM. 
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#65
11-03-2014, 05:47 PM
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remove the top plug from the 6Bk4 brightness down (crt dark) check HV again. be ready to pull the power plug if it starts to go north of 27kv
remember the top plug cap of the 6bk4 has full hv (so make sure you have it hanging away from any grounds).
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#67
11-03-2014, 07:44 PM
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does the picture width come in, or remain full....? Even a little....? If no, then I'm even more inclined to think about the hv rect. Also, I have never checked this but I would assume that a weak tube would be conducting less current, so.... less cathode current right....? Basic.... So how could a tube conducting less current be dragging down HV....? It should not.... I imagine when this is fixed, the picture should be a good bit brighter... And in the videos the scanning lines are nice and defined... Not really a bad tube looking..... right...? Also, Sams usually has brightness settings, specified for their measurements... you should probably look at them.... follow them.... Also, if recapping and on each part you "round" values up, down, or sideways.... after a few parts yer gunna have an entire tv with parts 20% off.... not good.... Be careful how you chose to determine filament voltage on the HV rect. You might just wanna get a new one off ebay... .
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Yes you can call me "Squirrel boy" Last edited by Username1; 11-03-2014 at 07:48 PM.
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#68
11-04-2014, 06:26 AM
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#71
11-04-2014, 06:58 AM
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ok so now we know for sure the HV is working and can focus on the regulator circuit.
you need to connect the anode lead back up on the regulator, then get some leads to the cathode and grid for the shunt tube. check the voltages of those leads compare to the sams. There is not much to go wrong with a CTC-12 regulator. I would suspect the pot but you said it was tested and (you actually tested the pot with a meter for resistance and wiper function). the 2 resistors are fairly close, that leaves the .0033 cap from cathode to grid. if it was leaky at all it would upset the shunt bias. Note the cap is a disc cap and not likely to be bad, but its pretty much the only thing left to check. OR you have a gassy shunt tube. do you see any purple glowing from the shunt tube? Last edited by DaveWM; 11-04-2014 at 07:04 AM.
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#72
11-04-2014, 07:05 AM
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ok so ill check the sams for the voltages on that tube. i also tried several other new reg tubes including an old one that has turned brown and never got a better result. just yesterday i took the single wire off the hv pot and and checked the ohms and the wiper, i think it was 500k and it varied just fine up and down. the .0033 i changed twice thinking one may have been bad. i use a fluke DWOM and it does work well thankfully,lol..
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#73
11-04-2014, 07:13 AM
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if you have done all that them I am out of ideas. It sounds like a regulator problem. Voltage checks should narrow it down.
Just to clarify you have max of 23kv with the CRT dark and the HV pot maxed out. You remove the cap from the regulator and it goes over 28kv You have tried KNOWN good shunt tubes. You have check the HV pot (and its ground is good) you replaced the .0033 grid to cathode cap.
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#75
11-04-2014, 07:24 AM
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Linear Mode
