GE 14T009 Restoration

[maxhifi]

Note Zeno said horizontal osc. Tube not output.

[Mre12ax7]

Since this is a lower end set the horizontal output tube is also the oscillator.
The vertical will sync fine.
All resistors connected to the AFC diodes have been replaced.
The 6AU8A sync separator tests fine on both sections with the sync section testing at 100%.

[dieseljeep]

Originally Posted by Mre12ax7

Since this is a lower end set the horizontal output tube is also the oscillator.
The vertical will sync fine.
All resistors connected to the AFC diodes have been replaced.
The 6AU8A sync separator tests fine on both sections with the sync section testing at 100%.

Sorry! Your statement regarding the horizontal output tube, being the oscillator is incorrect. The set uses a 6CG7 and a 12BQ6, horizontal output.
That model has always been tricky to trouble shoot in that circuit. There was two different variations in that circuit. One used the diodes and a 3AU6 audio IF tube and the earlier run used a 5AN8, for the audio and the triode side used as the horizontal AFC. I don't remember getting one of those sets working really perfect.

[Electronic M]

Originally Posted by dieseljeep

Sorry! Your statement regarding the horizontal output tube, being the oscillator is incorrect. The set uses a 6CG7 and a 12BQ6, horizontal output.
That model has always been tricky to trouble shoot in that circuit. There was two different variations in that circuit. One used the diodes and a 3AU6 audio IF tube and the earlier run used a 5AN8, for the audio and the triode side used as the horizontal AFC. I don't remember getting one of those sets working really perfect.

Agreed on the out put and osc being different tubes. There were 2-3 versions of this chassis. Not only were there ones with tube vs diode horiz AFC, the osc tube was different among them. One verion (IIRC the later one) used a 7AU7 as the H osc.

[Mre12ax7]

Yes I made a mistake about the tubes.
it uses the 7au7.
Which tested bad when I got the set and in there now is a new one.
I don't have any in my stash.
I do have 12au7s though and if I change the output tube to a 6 volt one it might work.
EDIT
Scratch that the filament current is different.

[Mre12ax7]

I just tested the 7au7.
One side is weak the other is bad.
Something is killing this tube.

[dieseljeep]

Originally Posted by Electronic M

Agreed on the out put and osc being different tubes. There were 2-3 versions of this chassis. Not only were there ones with tube vs diode horiz AFC, the osc tube was different among them. One verion (IIRC the later one) used a 7AU7 as the H osc.

I have to agree to that statement. I completely forgot about the 7AU7, one of GE's favorites. IIRC, all versions of the 14T009's used the 7AU7. I'll check Riders.
BTW, to the OP, the 12AU7 tube has a different heater current, 150ma @ 12 volts and 300ma @ 6.3 volts. You're stuck with the 7AU7.
You can't change the horizontal output tube to compensate for a heater voltage difference.

[dieseljeep]

Originally Posted by Mre12ax7

I just tested the 7au7.
One side is weak the other is bad.
Something is killing this tube.

Is the tube the original one? It's rather hard to kill that tube, unless the heater is over voltaged.

[Mre12ax7]

No.
The original was bad so I replaced it but the one that I put in is bad too.
I will have to get a few and see which one it likes

[Electronic M]

Test the tubes before putting them in. If you did not, it is possible the second 7AU7 was bad before it even went in the set. I've found NOS duds (and weak used tubes the same brand as on the carton) before.

Also occasionally a tube will have a defect that can damage the set....Like say a short between the plate of an IF tube to the grounded end of the heater....Which could fry the IF trans...There are many defects any given tube could have that could be harmful testing first saves you grief, and diagnostic effort at the cost of a little time.

[Mre12ax7]

Originally Posted by Electronic M

Test the tubes before putting them in. If you did not, it is possible the second 7AU7 was bad before it even went in the set. I've found NOS duds (and weak used tubes the same brand as on the carton) before.

That's what my buddy at the local tv/radio shop says.
I will have to go over there next week and pick up another 7AU7.

[Mre12ax7]

The TV is now fixed.
The 7AU7A was the culprit.
Now to watch Twilight Zone...

[zeno]

Rule was always try tubes first for the symptom before
you plugged in an iron or pulled the Sams. Then if no joy
repair it with a new tube in place. Sub back the old one
& give it a days test run.
One thing is garbage new tubes. Ones I remember were IEC
& Lindal. Many others to. The HOT's were guarantied to give
snivets. We got some in a by out & only used them in last
leg sets & sold at 1/2 price. Still made $$, only paid a dime
each. Only use brand name tubes that bear the name of a
major maker & u r good 99% of the time.
Glad you got her going, now time to get another on the bench !

73 Zeno

[dieseljeep]

Originally Posted by zeno

Rule was always try tubes first for the symptom before
you plugged in an iron or pulled the Sams. Then if no joy
repair it with a new tube in place. Sub back the old one
& give it a days test run.
One thing is garbage new tubes. Ones I remember were IEC
& Lindal. Many others to. The HOT's were guarantied to give
snivets. We got some in a by out & only used them in last
leg sets & sold at 1/2 price. Still made $$, only paid a dime
each. Only use brand name tubes that bear the name of a
major maker & u r good 99% of the time.
Glad you got her going, now time to get another on the bench !

73 Zeno

You brought back some memories about some of the tubes a buddy and I bought almost 60 years ago.
I think, there was around three firms that sold 33 cent tubes, advertised in Popular Electronics. Thirty tubes for ten bucks, what a bargain!
Then there was NJRT tube co. IIRC, they were Tung-Sol rejects. Olson had Akrad and Schield, they looked like Sylvanias.

[Mre12ax7]

Is there any kind of width control on these?
Its kind of stretched out to the right.
Or do I keep playing with those darn centering rings.