CTC 5 Low high voltage

[oldtvsandtoy]

aaa

[radiotron]

Originally Posted by oldtvsandtoy

ok here is where I stand right now. I pulled the shunt reg cap off the 6BK4 and disconnect the HV anode wire to the CRT Still only 9k. I then put the chassis in my other ctc5 and the same thing. Only see 4 fuses, one being a piece of wire. All good. Flyback is not getting hot. How much can I check with the chassis out of the set?

do you think the yoke could have anything to do with it?
OR a break in the board, cracked solder etc.?

[oldtvsandtoy]

aaa

[radiotron]

Originally Posted by oldtvsandtoy

yoke no, it was in two sets. Crack in the board? Dont know yet

if it is its proboby right under the hv cage i would look at all the retrace lines around there then try that

[DaveWM]

best way to trouble shoot HV would be to start with voltage readings on the horz out tube. the 5 has a 82 ohm resistor in the cathode circuit, and pulls cathode current thru the static converge pots. Get a resistance reading on the cathode pin of the tube socket and I will compare one of mine (or if you have a SAMs see if there is a resistance chart you can check). besides drive issues (which I doubt you have if the fly is not getting hot) You should check the screen voltage and with the plate lead disconnected and the tube pulled, check the Hor out plate cap lead and see if you have full B+ there. You did say you subbed known good tubes for horz out/damper/shunt/focus?

[oldtvsandtoy]

aaa

[DaveWM]

I would think you can do it all as long as you hook up a yoke and convergence coils

[oldtvsandtoy]

aaa

[N2IXK]

By "plate cap", DaveWM didn't mean "plate capacitor", but the physical connection "cap" on the top of the 6CB5 horizontal output tube.

Pull the 6CB5 out of the set, and measure the DC voltage on the wire that was connected to the top of it. Should be +375V or so. DO NOT try to measure this with the tube installed, as the high voltage pulses normally present will fry your meter!

Put the tube back into the socket, reconnect the plate lead, and measure the voltage on the screen grid (Pins 1 and 8). Should be about +175V.

Check the voltage on the cathode (Pins 3 and 6). Should be about +7.5V.