Admiral 19A1, no vertical sweep (video attached)
 

Well, here I am rolling along on BigAudioAl's Admiral. Complete recap, etc. Here's where I'm at. Thoughts?

http://www.youtube.com/watch?v=5qgng...ature=youtu.be

Have you either tested the vertical output and oscillator tubes or substituted them with "known good" tubes. Sometimes the substitution method is the best; that way there is no question about the electronic integrity of the vacuum tube.

There are so many possibilities that I guess people will hit on with this common symptom of no vertical sweep. I think that the next most important question to ask you would be: Was there vertical sweep before the "recap?" You could have a bad vertical output transformer, a potentiometer or a bad yoke. There are resistors across the yoke windings that can bad or have cold solder joints.

I'll stop there so some others can maybe elaborate. I hope this helps.

I didn't plug it in before the recap. The caps looked horrible, and I didn't trust them....I knew from experience that there was no way I was gonna get anything on screen unless I replaced those 6 kV deflection caps, anyway.

The only thing in the entire set that looks like a real abortion is the horizontal sweep transformer. New leads soldered on inside, and a wrapping of black tape on the outside. I'll assume that it's working though, since it has horizontal sweep.

I'll try tube substitution next. I just thought that it was really odd that I'm getting what sounds like horizontal sync bleeding into the audio.

The high megohm resistors near the vertical size control are reasonable suspects... I have seen the 10 meg ones *really* increase in value and kill the vertical, but the others are also suspect. Might want to ohm check the vert osc xfmr as well. Good Luck!
jr

Sounds like you are good for now in the horizontal realm with the exception of that audio/horizontal noise that you describe. That description of new leads being soldered on and "a wrapping of black tape" around the flyback transformer sounds scary and may be the heart of that noise you are hearing.

However, nothing in the horizontal circuitry is going to bring back the vertical sweep. Try the tube swap first, then work from there. Good luck.

I don't see a yoke, flyback transformer, or vertical output transformer on my schematic for an Admiral 19A1... It is a 7" electrostatic set. :)
jr

Someone mentioned to me that you can't use disc caps for the 6 kV vertical deflection, but they'll work fine for horizontal. Seems to me that I remember using disc caps for a VT71 I did years ago.

I'll hop on it tomorrow again and check those resistors. Thanks for the advice :)

I have used them also, for both Horizontal and Vertical coupling to the deflection plates. They worked ok, but with perhaps a little change in height/position as the set warmed up... no biggie... and certainly did *not* kill the vertical sweep.
jr

I don't know about the tv, but after yer video there was this GIRLFRIEND ZOMBIE ATTACK video I just had to see, and then I forgot about your tv a little more....

http://www.youtube.com/watch?v=PIVtr5kYvmU

Give it a try, you'll forget about that tv......

What TV were we talking about that was awesome.... seriously though I had the same exact set check the linea te controls on the back. they usually need a really good cleaning in my case it was simply burnt open I replaced it and the tv went back to normal. as for the black tape on the transformer be extremely careful I mean extremely careful the winding on that transformer use wire that is about the size of a human hair. my Transformer failed shortly after the set begin to make a quiet squealing sound I managed to solder the broken wire but when I moved it by accident it broke way back by the core my set is now DOA until I can find another transformer.

And believe it or not that could also be a tuner issue

First question is on capacitor C2B, the 50 uF section of the big white or tan filter cap under the bottom. I need to know where this goes, along with a couple pictures of the wiring at the end of said red wire.

Greetings from FixitLand!

No one's said this yet, surprisingly, so -- PLEASE turn the brightness DOWN on that set while it's showing only a bright horizontal line, lest you burn that line permanently into the phosphor!

Good luck on the fix,
--
J. E. Knox "The Victor Freak"

That is turned down. I played with the shutter settings on the camera.

As to the vertical circuit: once you get it working at all, I have a suggestion
for it that resulted in "oohs" at the picture it made on my lowly Pilot TV-37,
which has the same circuit idea.

My change was to replace the capacitors feeding the vertical deflection
plates with much much higher value 6kV ceramic ones. Actually my
set could use 3 kV ones but yours need the 6kV ones.

I would suggest 0.05 uF but 0.03 would work. Parallel cheaper
ones if necessary. Its still not terribly expensive. What this does
is increase the time constant of the circuit so that there is no
"exponential droop" during the 1/60 sec. scan time. Then remove the
odd 20 meg resistor between the vertical oscillator plate and the
second vertical output plate.

The waveforms on the plates of the two output tubes will then be
much more linear than the very odd ones shown on Rider's (
and which were similar to those on my Pilot before the mod.) And due
to the much larger capacitors they will be essentially identical on
the picture tube deflection plates.

Sorry to thread-crap Tim, but it seems that you haven't been reading (tracked) PMs, and I'm concerned about the remotes that you're forwarding to me. I just thought I would have heard something by now about what shipping will be for those and the other stuff. As long as you know where they are, I'm good.

I've been really busy with other things around the house and haven't had chance to get them forwarded yet. I'll respond to you in a sec.

The set as it is uses 6 kV caps.....right now I have to figure out where one of the four tuner wires goes, and I can't do that without taking the drum out of the tuner and tracking the schematic. Gonna be cold and snow is in the forecast here for the week, so I may end up staying on this set for a bit. My Mouser order for another set won't be in until late in the week for my Zenith 23 H chassis.....

No prob, it's all good, I was just concerned that they may have been lost somewhere around there. Probably my OCD.

Anyway, I saw the video and was surprised that it was a mere 2-meg download. Following this thread for sure to see the conclusion.

Well, now I've got this spare chassis in hand, and have figured out where all the loose wires go.

Attached them, and now nothing but a bright dot on the screen, no sweep whatsoever. I was able to blur it out with the focus control to the size of a quarter, but I couldn't even dim it down with the brightness control. Shut it off after about 30 seconds.

Why does it feel like I've taken a huge step backwards......

Tim,
My 19A1 did not like GTB tubes. Caused problems with one of the sweeps (vertical I think). Putting in older GT/GTA tubes worked better.
I have the same set in almost working condition (it has some wiggling of the picture) if you need any wiring pictures.

Maybe for vertical sweep, but I *did* have horizontal sweep before hooking up the one errant wire in the tuner, and before I realized that another wire was grounding out to chassis. The next step here is to pull the tuner drum and see what's going on with the wiring in there. I noticed that one of the wires inside the tuner was coming out the wrong hole, meaning that someone was in there fooling around at some point.

Did your set lose sweep entirely with the GTB tubes?

Swapped the entire tuner assembly from a parts chassis with no change whatsoever.

I'm stumped as to where to start. When one wire was unhooked from the tuner and another was (possibly) grounded to the chassis, I had horizontal sweep, and audio of some kind. Now with the wires hooked up properly, and even subbing a different tuner assembly, I've got zero sweep of ANY kind (just a super bright dot, I had to pull it way out of focus and dim it of course), and zero out of the audio.

Thoughts? :dunno:

Good luck! Hope someone has some suggestions.

For the time being I'd leave the tuner out of the picture. Check that all your B+ voltages are correct, then focus on getting your horizontal and Vertical oscillators running first.

Voltages are all screwy. I've got 295V on pin 3 of the 6V6 (should be 220VDC), and 261V on pin 4 (should be 200 VDC). Also showing 262V on pin 2 of the 6SL7 vertical output (should be 210 VDC). I've yet to find any negative voltage. Bear in mind also that my experience level isn't as high as a lot of you, but I'm learning quite a bit.

This set was a real hack job when I got it, so at this point anything could be suspect.

High voltages on the plate of the 6V6 seem to indicate the tube is not conducting. The question is now why? How about the grid and cathode. Are they where they belong?

Can somebody post the schematic? The screwy voltages sound like the audio output stage is used as B+ dropper for the IF strip, tuner etc.

http://www.earlytelevision.org/pdf/A...-sams-59-2.pdf

I can get back to checking the rest of the voltages, etc, tomorrow.....

Yep. There's suppose to be 125vdc on the cathode (pin 1) of the 6AS5 audio output. 210vdc on the plate(pin 7).

Everything seems to be running high. I've got 179 VDC on pin 1 and 286 VDC on pin 7.

That's strange. What's on pins 2,5,6 while you're at it? Got another 6AS5 to try?

166 on pin 2, 164 on pin 5, 293 on pin 6. Might have one laying around here.

Better check R48,R49 too. Those two resistors bias the grid.

Pin 2,5 should be about half of whatever's on pin 6 - because the voltage on pin 6 should be basically divided in half by the 470k and 560k resistors in series going to ground. The grid(pins2-5) get's it's bias from the junction of those two resistors. Not sure why your source feeding pin 6 is so high. You might go back and measure the AC voltage on pins 4,6 of the 5Y3. Suppose to be 240vac from each pin to ground. Then 240vdc on pins 2,8.

R48 is high....should be 560K, it's reading 704K. R49 isn't terrible, it should be 470K, testing at 496K. I should have that value here to replace.

704k isn't that far out. Basically your measured 166v is roughly half of 293v.
Better back up and measure AC volts on pins 4,6 of the 5Y3 - should be 240vac each pin to ground. Then 240vdc on pins 2,8. What's your AC line voltage?

With the resistor changed to 550K (closest I could come), voltages dropped to exactly 152 on both pins 2 and 5. Still no changes otherwise, not that I'd have expected there to be at this point :)

Pins 4 and 6 are at 280 VAC, and 2 and 8 are at 310 VDC. Line current is 118 VAC.

That seems awfully high. Honestly I'm not familiar with how much current the HV oscillator circuit pulls from the LV supply on this set. Possibly if that's not running and producing HV, that it's making the other B+ voltages high. It's as if there's hardly any load on the LV supply. :scratch2:

Read back and didn't see where you measured voltage on pin 3 of the 6V6 HV osc. Sams says 3 volts, which would be 30ma across that 100 ohm cathode resistor. I suppose that's a significant part of the total load on the LV supply? Were these supply voltages always high, even when you had HV?