Admiral 19A1, no vertical sweep (video attached)

[Kevin Kuehn]

When you change the horizontal hold, it appears that you're actually get lock at more than one higher frequency.

[Kamakiri]

That's what I was thinking too. I was pretty careful about that, but I suppose anything's possible. I'll double check my work.....

[Kamakiri]

Everything seems fine....

One thing to note....I can't get more vertical out of it than I've got.

[jr_tech]

Got any more 6SN7s and 6SL7s to try? how are the dc voltages in the vertical & horizontal circuits?

jr

[Kamakiri]

Tubes tested good, replacements yielded no change. I'll test circuits as time permits this evening. Really appreciate you guys sticking with me in this thread

[kvflyer]

Originally Posted by old_coot88

The POP mighta cleared a tin whisker.

I know that I am 24 hours "late for the party" but that very symptom had me pulling my hair out on an Admiral 26R12. It was on the height control. The clue which I failed to pick up on was that varying the control did not change the voltage. The set started out good. But then there was a "POP" and I lost about half of the vertical height. To me, a lesson learned. I was not familiar with tin whiskers at that time. So, you may be good to go for that.

You may want to try brushing the controls G E N T L Y to get any tin whiskers away. They can be from the terminals to the control case and drive you crazy.

[old_coot88]

In the schematic for chassis# 19A1,
There's four components in the H. osc circuit which, if they've been replaced and one were inadvertently the wrong value, could throw the frequency 'way off. They are:

C36, .01 uf. comes off pin 6 of H. osc tube
C37, .001 uf. connects between yel. and brn. leads of T4
R42, 39K goes to pin 5 of H. osc tube
R43, 39K goes to pin 4 of H. osc tube

(color code for 39K = orange-white-orange)

[Kamakiri]

C36 in my Sams is a .002@600, "de-emphasis", and C37 is a .005 audio coupling cap. I'm working with set 59, folder 2, date 4/49. Matches what is in my set.

I'll just check those specific caps and resistors. Hang tight.

[Kamakiri]

Okay, my diagram numbers them C46 and C47. C46 is fine, C47 is an original Micamold that I never replaced. Time to give that a try.

[jr_tech]

Originally Posted by old_coot88

In the schematic for chassis# 19A1,
There's four components in the H. osc circuit which, if they've been replaced and one were inadvertently the wrong value, could throw the frequency 'way off. They are:

C36, .01 uf. comes off pin 6 of H. osc tube
C37, .001 uf. connects between yel. and brn. leads of T4
R42, 39K goes to pin 5 of H. osc tube
R43, 39K goes to pin 4 of H. osc tube

(color code for 39K = orange-white-orange)

Translation to Sams numbers

C36 = C46
C37 = C47
R42 = R81
R43 = R82

jr

[Kamakiri]

No change. Should have just done C48 while I was in there. I'll change out C48 and check those two resistors next. I'll get this yet

[Kamakiri]

Changed C48. R81 (R42) was at 52K, R82 (R43) was at 73K. Put in brand new 39K 1 watt 5% resistors. No change in the picture.

[Kevin Kuehn]

Did your supply voltages ever come down closer to spec? What DC voltage do you read now on pins 4-6 of V13B(horz osc)?

[jr_tech]

And if the voltages are *still* too high, perhaps use your variac to reduce until they are normal and see how the horiz behaves.

Is 10 k resistor from horiz hold to the transformer ok? How about the 50 uuf cap to the sync circuit? Does the "parts set" have a good horizontal transformer if you need it?

jr

[Kamakiri]

Originally Posted by Kevin Kuehn

Did your supply voltages ever come down closer to spec? What DC voltage do you read now on pins 4-6 of V13B(horz osc)?

-69 VDC on pin 4, 2.44 VDC on pin 6. Still high.