ctc12 clone beam current

[Bill R]

How would a leaky cap of pin 7 of the regulator tube affect it's operation? Just curious.

[Username1]

That should bring down the dc component as well.... But he said all those caps
were replaced....

.

[DaveWM]

SB is right, that was discussed as well.

all the usual suspects were check or replaced some more than once.

the two 1.5 meg resistors check and replaced
the .0033 grid to K disc cap, replaced SEVERAL times
the HV pot checked for operation
The .1 Filament to chassis, replaced.

when he said he saw sparking around the heater that is what got me thinking to check heater potential. Voltage checks should give us the answer.

I sure hope this is it as I am out of ideas.

[Username1]

Sounds like you nailed it !
I don't remember anything about sparking....
Fingers still crossed.....

.

[DaveWM]

Originally Posted by Username1

Sounds like you nailed it !
I don't remember anything about sparking....
Fingers still crossed.....

.

That came up in conversation, after I told him to try a working tube from another set. He has the cover off so it can be seen, which may have gone unnoticed before if it was just installed with the cover in place. This is why long distance diagnosis is so hard. Its nearly impossible to cover all the bases. But to his credit he did note it and report back, with out that little nugget I would not have thought to check it. The knowledge of how a working regulator tube looks is kinda hard to describe, which is why I wanted him to look at one in a good set. So while powering up the bad set he was looking for the correct operation.
I just really really hope this turns out to be the problem.

[Bill R]

Originally Posted by Username1

That should bring down the dc component as well.... But he said all those caps
were replaced....

.

I knew it had been replaced, I was just thinking what it's function was. I assumed it was a ground path for the ac pulses on the tube.

[timmy]

ok the .12 cap that i replaced was in question as to what values i put together to make the .12 , so here it is .1- 630v and a .022- 630v in paralle. ok now on to the voltages, pin 1- 6bk4 to ground 407 v maybe the grid here was up a bit at the outlet, pin 2- to ground 94 v . pins 1&2 - 315 volts and pins 1&7 - 315 volts at first start up this 315 was 330 volts but then dropped. each filiment wire to ground was 94 volts so after checking these voltages i did not go into the other set to compare because if this voltage is to be under 225 volts then clearly those resistors must be a problem and i will have to check them. the 180k and 150k thats next....

[Username1]

Yah, doing the math, should be around 180v give or take tolerances....

.

[DaveWM]

I just pulled the back of mine, 177v pin 2 to ground about -210 pin 2 to pin 1.

I am posting up a very short video, should be there soon. I will leave the set out in case Timmy gets the HV working and has focus issues, I can look at how I have mine setup.

my video ran out before I could get the pin 2 to ground but I do show the 2 to 1 DC voltages.

[DaveWM]

https://www.youtube.com/watch?v=ALle...ature=youtu.be

here you go timmy

[timmy]

well i got a problem here the 150 k and the 180 k i had already put resistors in series awhile ago and the 150 tests at 156k and the 180k tests at 182k so im looking for maybe a mistake on the 400v source or the 390v source maybe i crossed one of those sources. i just cant believe this crazyness. i need a smoke first.

[DaveWM]

if the resistors check out you will need to go back to where they connect up.

the 180k goes to B+400v check there with meter, then check where the 150k goes to ground should be 0v there, then check the junction, should be +180v there. has to be.

if you replaced the resistors you need to make sure you connected up to the correct location, esp the B+ side. During our talk IIRC you said it was connected to the output of the 1s diode of the doubler, that is NOT where the 400v is but more like where the 200v is. the 180k goes to where the 400v is.

if you have it hooked up right (180k to 400v) and the junction is still around 90v, it would mean you have a leak to ground somewhere, disconnect the wire at that junction and check the voltage at the junction of the two resistors again, if it pops up to 180v from the 90v then..

perhaps that .1+.022 cap. if this is the case try disconnecting the .1+.022 cap (lift the ground side) and check the voltage again.

[timmy]

ok i changed the resistors here and one end 180k starts at the diode and confirmed 400v , then goes to a tie strap and then the 150k from the tie to ground its all in the right place.

[timmy]

what junction, the filiments to ground ? so at this point it could be any cap from a positve source to ground causing the filiment voltage to be hi or am i off here.

[DaveWM]

disconnect the wire that connects to the junction and so all you have is the two resistors in series, then read the voltage at the junction.