I dug up a whole page of 20T1 production changes in the Wallace Teleaide for Admiral. Click for a larger version.
https://c5.staticflickr.com/9/8032/2...cb3d8a3c_n.jpg


No mention of C404 but this may explain it. There were parts shortages due to the Korean conflict and high consumer demand so substitutions were made.
https://c3.staticflickr.com/6/5231/2...e979182e6d.jpg

Wow, Thank you Bob. Is there anyway that I can save those prints? I tried to save them as an image and the resolution was bad. But I can view them very clearly.

Thanks again.

Clicking on them should take you to Flickr where you'll have options to save it in a variety of resolutions. Here's a link to the full size version.

https://c5.staticflickr.com/9/8032/2...b897ea12_o.jpg

Got it!

Thanks Bob.

As I do with the radios and TV's I restore, I label all the components using the SAMS designators. This allows me to see what is in the TV, part-by part. Also I check the component against Sams schematics. When done, I compile my resistor and capacitor parts lists.

Next up is to order what I need.

http://i1060.photobucket.com/albums/...pstik9fqwi.jpg

The parts are ordered.

I ordered my E-Caps from Digikey and they will be here in a day or so. So I thought that I would start on re-stuffing the 2 E-Caps. 1 E-Cap is a 4 section and the other is 3 sections. Basically what I do is to remove both cans from the chassis, cut them at the base, clean out the cans, and build up the E-Caps using a new base from a donor E-Cap. This way the terminals are nice and new, but more important, the twist lock tabs are new and shouldn't break off when installing the re-stuffed E-Cap.

1) The first thing I did was dig out my donor cap for the new base. I got a bunch of these at an auction for almost nothing. The E-Caps are all 4 sections. This way I can use their bases on anything I should need on my TV's and radios.

2&3) I cut the bases off using my band saw. I cut just above where the smaller diameter can meets the base. Once the base is cut off, I true up the base using a flat piece of 80 grit sandpaper to bring the edge of the can down to nothing so only the base is left. I then drill a 5/32 hole in the center for the wires to pass through. I suppose you could drill a hole by each terminal and then 1 for the ground wire.

4) I then take some 1" schedule 40 PVC sprinkler pipe and true up 1 end using my disc sander and 90 degree guide. Once trued up I mark that end with an arrow using a Sharpie. I then mark off a 1 inch mark and again cut off the 1 inch piece using my band saw. I then true up the end of the remaining stock using my disc sander and 90 degree guide. Then I mark off 1 inch and cut another piece of PVC pipe. I then clean up the edges using my hobby knife and some 220 grit sandpaper.

5) Then I mix up some 15 minute epoxy and apply it to the end marked by the arrow using a flat toothpick. I then place it on the base and then again using a flat toothpick, I apply a small amount of epoxy around the inside perimeter. Once that is done, I make sure there is no epoxy on the outside of the PVC tube. This would cause a problem when the can from the original E-Cap is placed over the PVC pipe and pushed down.

6) I let them assembly to dry overnight.

I'll then add the new E-Caps to the new base assemblies. Then using the original E-Caps I'll cut off the cans from their bases and true up the cans to be placed over the new re-stuffed bases.

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My E-Caps came in today so I decided to build them up.

I use hot glue to hold them together and some 600 volt solid wire for the leads. I color code each cap and make notes as to what cap, wire color, goes to each symbol. I want to match the originals.

On the C2 which has only 3 caps, I used some balsa to from some spacers for the lower cap. This help stabilized the whole thing.

The pics speak for themselves.

Later tonight, I cut off the original cans, clean them and then the E-Cap re-stuffing will be finished and they'll be ready to install into the chassis.

http://i1060.photobucket.com/albums/...psdwyiydj6.jpg

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Nice very nice :-) All the best,Tom.J

Thanks Tom.

Both E-Caps are soldered into the chassis. Now on to getting the wires back on.

http://i1060.photobucket.com/albums/...psu3acucpw.jpg

That's a very neat E-cap rebuilding method you have. :thmbsp: I need to get me some of that schedule 40 PVC tubing. One obvious short cut would be to saw the tops off the cans while the bases are still mounted and wired to the chassis. Unfortunately some times they land in locations too tight to get a jewelers saw and sanding block in there.

Thanks Kevin.

I wired in the E-Cap cans and tacked in the 2 other E-Caps. I then carefully powered up the chassis. At 110V mains, I got 208V B+ ( 238 listed in Sams), and a raster. No audio though. Though the "hash" went up and down with the volume control. Looks like all the front panel controls did something. After about 2 minutes, I heard a "pop" from under the chassis. I quickly powered down and did a visual. Didn't see anything. So I powered it back up and still no audio and this time no raster. No HV either. So I shut it down till I can replace all the paper caps and such.

When looking this thing over when I first got it, I was amazed that there weren't any shorts because of the way the components were wired in. When replacing the caps and resistors, I do a complete and through job on lead dress.

I'm expecting my order from Just Radios to get here early next week.

Just don't change IF lead dress...You may need to do an alignment afterwards if you do.

Yeah, the IF section is nicely done. It's the other part that needs a lot of TLC.

Guys, I need to replace the wire from the cap of the 6BQ6GT to the flyback. The cap connector came off and when I stripped the wire back some, it was all green and the green just powdered off. Not good. I need to replace this wire that is about 6 inches long. Looks to be about 20 awg. I'm thinking the some UL1015 600 volt stranded wire would work.

http://i1060.photobucket.com/albums/...psceaksjkv.jpg

The insulation on the wire you are thinking of using will not last very long due to the 3kv to 4.5kv pulse on that lead. I do not have the Belden type number in front of me but I would use a bit of focus lead from a BPC junker for that lead. All the best, Tom.J

A couple of layers of shrink sleaving will work in a pinch. :scratch2:

I have a junker 19" B&W tv I got off the curb one day. I'll get the wire off of the HV anode wire from this tv.

I didn't know what kind of voltages to expect. Now I do.

If you have an old CRT monitor kicking around, you could steal its high voltage wire off it. Those monitors also usually have a fair amount of high voltage caps of the sort useful in TV restorations.

Good idea, but no old monitors laying around. I'll get the HV wire from the 19" TV.

Well, I just stripped the wire back another 3/8 inch and it was good clean wire. I cleaned up the plate cap connector and re-soldered it back on to the wire. All is well now. I do have some 20K wire I salvaged from the 19" TV.

I've started on changing a few resistors that were basically stand alone. I'm waiting for my Just Radios order to come in. Then the recapping will take place in earnest.

My order from Just Radios came in! Full speed ahead. I placed the order last Monday night the 26th. Great service. Just less than a week to get here.

Changed some resistors and caps that were easy just to get into it.

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That really is a labor of love. :thmbsp:

Recapping continues. I replaced the 1.5K 10W Candohm resistor with a 1.5K 50W chassis mount resistor. I was going to use a 25W resistor but the 50W was less than a buck more and I feel it will work better to dissipate the heat.

I'm using 1W resistors to replace the 1/2W carbon composition ones. I'm staying with replacing 1W with 1W and so on. In one instance, I used a 3W resistor instead of a 2W.

When I replace a component, I check it off my list, and then highlight it on the schematic. Helps keeps track of what was replaced and a "visual" of my progress.

I'm also checking each removed resistor for its value and the value of its replacement. If interested, I'll publish that list when done.

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I think I found out why I lost HV on the power up. Looks like R82 a 6.8K resistor is open. I'm redoing V16 a 6BQ6GT Horizontal Output tube. This resistor was buried way down.

The resistor has a couple of small cracks on one end. Other than that the resistor looks normal.

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Well, I got V15 and V16 done. It was a bit tight! I like the way Admiral did the 3 resistors on V15!

Here are some before and after pictures.

Looks like VK won't allow me to upload any more pictures. I'll have to contact the Admin.

I decided to power it up again to check my progress so far. The good news is that it powered up nicely and my B+ is 244 volts. Sams lists 238 volts. I also have a raster and each control seems to do something. Like Brightness does control the brightness and so on. I only have a low level buzz coming through the speaker which can be varied with the volume control. Also no video.

I tried wiggling each tube but that didn't help. On a few like the sound IF amp it clicked pretty loud in the speaker. Seeing I haven't gotten to the IF stages yet, I'm not surprised.

What's left to do is the 3 IF stages, Video Detector, a little in the Video Amp, Sound IF amp, Ratio Detector, Sync Amp-Sync Separator, and the Sync Clipper.

Once these are done then I'll have to get into the troubleshooting phase. So far so good.

http://i1060.photobucket.com/albums/...psptpisiym.jpg

I recapped the Video Amp, Sync Amp-Sync Sep., and Sync Clipper. I powered it up and still no audio except some hash which goes to a loud buzz when I touch the center wiper on the volume pot. Basically the same thing as before. I'm thinking that the trouble lies in the IF stages or tuner.

BTW, the tuner inserts have numbers on them that seem to correspond to channel numbers. Does the ones with "4F" on them equal channel 4? I need to know so I can be sure I'm on channel 4 because my CD player and RF modulator are set to Channel 4.

Another thing, I remember seeing something about hooking up a CD player directly to the video section? thus bypassing the tuner. Can this be done?

Recapping that's left are the 3 IF stages, Sound IF Amp, and the Ratio Detector.

Thanks.

If you have a source with separate audio and video (not RF) output, you can temporarily connect that video source to the video input of your TV. Typically, this is a spot directly after the video detector, where it sends the video signal to the grid of the video amplifier tube. This diagram is for a different TV, but it should give you the general idea:

http://antiqueradio.org/art/A-V_Adap...oInjection.jpg

If the picture looks dramatically better when you inject the video, that suggests that you have a problem somewhere upstream of the injection point, in the tuner/IF/detector stages.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Phil,
Thanks! I made the box and used alligator clips. I pulled the cap off the volume pot and clipped on the audio. Then I had a spare 6AU6 tube so I bent #1 pin up and soldered on a small extension. I inserted the tube and clipped on the video.

I have both audio and video now. I'll trouble shoot the IF stages now.

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I have a question about my problem. It is either in the IF stages or the tuner. Is there a way to substitute the tuner? That way I could really narrow down the problem.

I'd look at the IF stages first. Tuners are comparatively bulletproof in my (limited) experience. Make sure the tuner tubes are good and its contacts are clean.

Yes, there are ways to substitute for the tuner. Back in the day, they sold "tuner subbers," little gizmos that do what they sound like. You can also inject an IF signal (and do many other tricks) with a BK 1077 TV Analyst like this one:

http://antiqueradio.org/BK1077BTelevisionAnalyst.htm

You can also make simpler measurements such as checking the gain of each stage, checking voltages on each tube, etc. If you have a voltage chart, that's one easy way to start.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Phil,
Thanks for the suggestions. I forgot about the voltage chart. I'll do the resistance checks first then the voltage checks.

Success! I did the resistance checks per the chart in Sams and found V5 pins 5 and 6 showed open when they should have had 2.6K to pin 8 of the LV rectifier tube (120V). I checked the schematic and R29, a 1K resistor, was between the tube pins and 120V bus. I then did a visual on the resistor and it looked good. I then bumped it with my finger and a lead pulled out of the resistor! I replaced the resistor and now I have very good audio and video through the antenna terminals.

I have to finish replacing the rest of the resistors and a few micas yet. But getting a good picture and sound is very encouraging.

BTW, the CRT, a 14CP4 tested very low on my BK 467 but played in my AMC TV came up real good with a very good life test when I gave it to my friend who has a Beltron. He rejuvenated the CRT for me.

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Nice bit of troubleshooting! :yes: I stand in awe at the quality of your overall workmanship sir.

Phil was the one that tripped my mind to use those charts in Sams. Thank you for the kind words.

I looks like one of those foreign made resistors, that Admiral used at the time.
I like the yellow caps for old set restorations. They're so small, compared to the originals and the leads are usually long enough to do a neat job.

Dieseljeep,

Could be. Their leads are very thin. Agree on the yellow caps!

I pulled the entire sub-assembly from the chassis. It was a lot easier to work on. I finished the audio section of V7, V8, and V9. Cleaned up the entire area too.

On to the real IF section on the other side of the sub-assembly.

http://i1060.photobucket.com/albums/...psw1ozjk4v.jpg

The IF section is finished. Now on to the topside to clean it up and re-installation.

http://i1060.photobucket.com/albums/...psbo1jykay.jpg