Weirdness on an Admiral 22X12!!!
 

Picked this set up over the weekend, your typical 12" late 40s single chassis Admiral, and since I had to pull the chassis to get it into the basement safely, figured I might as well recap it.

Got it all recapped, and had sound, reception, focus, and raster, but no vertical deflection. Dead primary winding in the VOT. Just happened to have a spare VOT here, a brand new Stancor, so I put it in. The primary resistance was off slightly (1.1k vs spec of 730 ohm IIRC), but secondary was dead on.

Installed it, and I now have vertical deflection, BUT no audio, no signal....just retrace lines. Focus changes nothing on the screen, and the brightness does absolutely nothing....the screen is always at one set brightness.

I'm stumped. I can't find any wires I might have crossed, anything. Ideas? :sigh:

Sams link: http://www.earlytelevision.org/pdf/a...sams_100-1.pdf

Poltergeists? Open focus coil?

It was all that testing that did it. When my Wilcox-Gay set needed a VOT, I just pulled one out of the first junker I laid my hands on, easy peasy. :stupid:

Tim,
Check the wiper arm of the focus control and the associated 750 ohm 7.5 watt resistor. I've replaced at least 4 focus controls in Admirals this past year. The focus control supplies B+ to the audio and video amp plates, about 300 vdc.
Ed

Having done a few of these I did a preliminary replacement of the 750 ohm resistor before I even powered it up. Weird thing was that the focus control was working fine before I changed the VOT.

I even tried a different Admiral speaker, as I remembered that these sets used part of the speaker in the focus section of the set.

I definitely can't rule out poltergeists!!!

Well, the poltergeist was me :twak:

Started testing voltages and began to remember the circuit that I knew so well. I had perfect voltages on C1, meaning that the choke was good. Followed the circuit path over to C3 and nothing. Zip zero dead.....leaving that new focus resistor and the focus coil. Voltages coming in to the focus coil were fine, and nothing on the other side of the coil. Touched my probe to the newly installed NOS adjustable resistor and the sound blinked on.

It was a bad solder joint that I couldn't see :tears: . Apparently there was enough solder *on* the joint to hold the resistor firmly in place, but it wasn't making contact with the lug due to the wax buildup that I thought I had cleared out.

She looks good now! And it was a great refresher on the circuit.....

Bad slobber joints will get you every time! I just rewired the jack on an active Jazz Bass because of poor soldering. It was randomly cutting in and out on him.