Still Having RCA 8TS30 Issues

[jr_tech]

30 volts across a 10 ohm resistor would be 90 watts...resistor would be getting very hot!

jr

[Chris K]

When I measure it next, if I’m getting the same thing I’ll post some photos of the measurements and pins. That way if I’m doing something very stupid I won’t end up dragging u guys down any rabbit holes

[Chris K]

It is 3 millivolts. Sorry and thanks for picking up on that. My bad. The “m” next to the “V” was microscopic!

[Chris K]

I mean 30 mV

[jr_tech]

Originally Posted by Chris K

It is 3 millivolts. Sorry and thanks for picking up on that. My bad. The “m” next to the “V” was microscopic!

And they seem to get smaller every year!

jr

[Chris K]

Originally Posted by jr_tech

And they seem to get smaller every year!

jr

You're right about that!!! I paralleled the 1.5k with the 10k resistor to bring the resistance down to 1.3k. Same symptoms although the 135 volt line came up to 105V

[Chris K]

Not sure where we go from here. The only thing I can find off is a lower than expected voltage. Can a resistor create a stable unstable condition? If I had not bypassed it by injecting an IF signal directly into the video IF, I would suspect the tuner but that can’t be it. I guess I need to start replacing resistors in the sync and horizontal circuits even if they test ok. At the least it will eliminate them as the culprit.

[Chris K]

I think this one may go on the back burner for a while. I’m at a dead end with it. Sometimes it’s for the best to give an old chassis a rest and stop pokin and burnin it! Appreciate everyone’s advice and interest. I’ll be back with it in a bit.

[Chris K]

Tryin to give it a rest but just a few more observations. I put the 10BP4 back in the chassis. The symptoms are the same but I noticed it’s less of an issue when the set is cooler. When it’s in sync it’s a beautiful picture and the resolution is very good. That’s why this irks me as much as it does. If I could just get the picture stable it would be a great performer. Once it heats up the problem becomes worse. I don’t know if that means anything or points towards a resistor issue. Trying to walk away but it’s tough. This TV came with it’s original stand so it’s a real find.

[old_coot88]

I feel your frustration bro. I might've missed it, but have you checked voltages on:

V118 (6SK7) 1st sync amp ----- pertinent voltages are pins 4, 6, 8 (that's G1,G2, plate)

V119 (6SH7) sync separator --- pertinent voltages are pins 4, 6, 8 (that's G1,G2, plate)

V120 (6SN7a) 2nd sync amp -- pertinent voltages are pins 1 & 2 (that's G1 and plate)

Are those tubes lighting up good? If any are metal, they should be getting warm after a few minutes running.

[nasadowsk]

Temperature related suggests drifting components. Got a can of freeze spray or such handy?

[Chris K]

Not handy but I'll get some

[Chris K]

Originally Posted by old_coot88

I feel your frustration bro. I might've missed it, but have you checked voltages on:

V118 (6SK7) 1st sync amp ----- pertinent voltages are pins 4, 6, 8 (that's G1,G2, plate)

V119 (6SH7) sync separator --- pertinent voltages are pins 4, 6, 8 (that's G1,G2, plate)

V120 (6SN7a) 2nd sync amp -- pertinent voltages are pins 1 & 2 (that's G1 and plate)

Are those tubes lighting up good? If any are metal, they should be getting warm after a few minutes running.

I'll check those tonight. Yes they are warm and NOS but I've tried several tubes from my stash and from the parts chassis with no change.

[jr_tech]

It might be worthwhile to check all power supply voltages cold vs hot.

jr

[old_coot88]

Originally Posted by Chris K

I'll check those tonight.

Cathode is ground on all 3 tubes, so wasn't included in voltage chart.