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  #1  
Old 05-03-2018, 10:38 AM
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bandersen bandersen is offline
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Admiral T2301DR restoration

A local collector dropped off a couple more TVs for me to restore. One is a GE 800 bakelite locomotive. I'm looking forward to that as I sold my unrestored example before I ever got a chance to work on it.

First up though is the other - an Admiral T2301. It's a 21" set from around 1957 in a metal cabinet. I've only worked on some portable sets from this era, but not a full size table top. It's in good condition with all the original knobs and back.





I don't see much evidence of servicing.


Had to pull the knobs, unmount the controls, disconnect the CRT and remove some screws to get the chassis out.




It has the typical crumbling yoke cover but it still has enough integrity to hold together.


The centering magnets are mounted in a manner I haven't seen before. They are on a piece of masonite and held tight against the yoke by three springs. I wonder if it's aftermarket or a production run change ?



Finally, here she is up on the workbench. No corrosion, rodent damage or any other sign of trouble



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Old 05-03-2018, 03:47 PM
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I pulled the 5U4 rectifier and did a power up test. All the tubes lit up (or so I thought) and voltages on the power transformer secondary looked good.
I figured this would be a good opportunity to try out my Tele Check external test CRT.
It has it's own yoke with long wires ending it alligator clips. Same for the CRT socket and HV lead. I read the hookup instructions and think I got it all correct.


I put the 5U4 back in and hooked up a meter to monitor the B+. Turned it back on, but no B+. Checked the fuse - it's good. Hmm...

Traced out the circuit and discovered there is a B+ interlock in the speaker plug. I unmounted it from the cabinet and tried again.

Now, I got good B+ - right on spec and hiss from the speaker but no HV.

Closer look at the tubes revealed the damped tube was dead.

I replaced it and tried again. Bingo! I have a raster. Not enough height, but a bright image and sound. Reception is only fair.





After a little control tweaking with the height control maxed out. Great starting point for the restoration. No doubt some of the caps are leaky and tubes weak.
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Old 05-03-2018, 05:51 PM
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That is off to a good start.

Looks like we have the same test jig...Mine did not come with the HV lead. At some point, if you could post a pic of the ends and the length that would help me make a better replacement for mine.
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Old 05-03-2018, 07:01 PM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Electronic M View Post
That is off to a good start.

Looks like we have the same test jig...Mine did not come with the HV lead. At some point, if you could post a pic of the ends and the length that would help me make a better replacement for mine.
FWIW, Mr. Anderson!
The centering device is original!
I worked on a lot of Admirals of that era. The one you're working on, has the PC board IF, which is 21 mhz. All the one sold in the Milwaukee were 41mhz IF because all of them were UHF equipped. The 21mhz tuner uses a 6J6 osc mixer where the UHF 41mhz model used a 6U8. Why Admiral did it that way is any ones guess. The 41mhz IF panel is hand wired.
The Thomas CRT is original. They stood up better than the National Videos, so it might still be usable.
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Old 05-03-2018, 07:36 PM
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We had that model in Australia (or very similar). It was one of the first TV,s I restored as a teenager. It has those strange PCB mount caps which I assume are paper in construction. I found them to be quite leaky as I recall and replaced the lot. Access for measurements while the set is running was difficult with the vertical chassis and pcb,s. I replaced the CRT with a regunned one at the time as the original was very weak. It made a nice pic once restored IIRC. I look forward to watching your progress.
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Old 05-04-2018, 09:49 AM
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Quote:
Originally Posted by Electronic M View Post
That is off to a good start.

Looks like we have the same test jig...Mine did not come with the HV lead. At some point, if you could post a pic of the ends and the length that would help me make a better replacement for mine.
I will take a better photo soon, but for now here's a closeup from a photo above. It's about 5 feet long with an insulated alligator clip on the end. The insulation seems a little thin to me but I haven't had any trouble with arcing.



Quote:
Originally Posted by dieseljeep View Post
FWIW, Mr. Anderson!
The centering device is original!
I worked on a lot of Admirals of that era. The one you're working on, has the PC board IF, which is 21 mhz. All the one sold in the Milwaukee were 41mhz IF because all of them were UHF equipped. The 21mhz tuner uses a 6J6 osc mixer where the UHF 41mhz model used a 6U8. Why Admiral did it that way is any ones guess. The 41mhz IF panel is hand wired.
The Thomas CRT is original. They stood up better than the National Videos, so it might still be usable.
Thank you for the info Yes indeed, the CRT does have some life left. Not great but after a gentle restore cycle on my CR70 the emission test does get into the green.

Quote:
Originally Posted by irext View Post
We had that model in Australia (or very similar). It was one of the first TV,s I restored as a teenager. It has those strange PCB mount caps which I assume are paper in construction. I found them to be quite leaky as I recall and replaced the lot. Access for measurements while the set is running was difficult with the vertical chassis and pcb,s. I replaced the CRT with a regunned one at the time as the original was very weak. It made a nice pic once restored IIRC. I look forward to watching your progress.
I've tested a few of those vertical blue caps mounted on the PCBs and was surprised to find they all test good. No leakage and close to the stated values. That makes me wonder what they are made from. I'll try to break one open and find out.
The same goes for the axial blue caps on the rear of the chassis. All have been good. Now the black beauty / bumble caps are another story. They have all tested leaky.
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Old 05-04-2018, 12:11 PM
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[QUOTE=bandersen;3199026]I will take a better photo soon, but for now here's a closeup from a photo above. It's about 5 feet long with an insulated alligator clip on the end. The insulation seems a little thin to me but I haven't had any trouble with arcing.





Thank you for the info Yes indeed, the CRT does have some life left. Not great but after a gentle restore cycle on my CR70 the emission test does get into the green.
There was two years of that chassis and tons of variations. Some used a 6AL5 and that model uses a selenium dual diode. The Audio board in the later production was hand wired and used a 6DG6 audio out tube.
Some had the choke mounted on the speaker and some, the yoke was hard wired instead of plug-in.
They must've wanted to keep their engineering staff busy.
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Old 05-04-2018, 03:22 PM
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Bob, when I saw the picture of your Admiral TV in the first post of this thread, it reminded me of a 21" Admiral table model TV I had in the early 1970s. It was a trash find in my old neighborhood near Cleveland (much closer to the city than where I live now), and was in a white cabinet with the controls (volume, channel selector, vert. hold, et al.) under a trap door at the top of said cabinet. The set worked amazingly well for its age (since it did not have a UHF tuner, I would place it some time before 1964) with its original tubes, CRT (no brightener) and caps. (Bear in mind, this was decades before Videokarma and long before I knew that all old TVs made before about 1967 need to be recapped.) Unfortunately, I had to junk that set when I moved in 1972 (long story and OT); needless to say, I hated to part with it, especially since it seemed to be working so well. The only other TV I had at the time that worked better than the Admiral was a Zenith K-2739 23" console, which I also had to get rid of when I moved.

I'm glad your Admiral TV is working as well as it is. Hook it up to a DTV converter box and an antenna (or cable) and you should get an excellent picture; those old TVs were built to a level of quality we will never see again.

I noticed, however, in one of the pictures of your set's chassis, that two tubes, the horizontal output and the LV rectifier, were glowing much, much brighter than they should have, and I also did not realize the CRT in your set was so weak until I read the post a second time. Are those tubes glowing normally, or is one of them shorted? In my years of fiddling with electronics, I have only seen one tube glowing that brightly; that was in a Zenith radio I plan to restore one of these days. The pilot light had burned out, and was putting so much of a strain on the 35W4 rectifier tube that it was causing said tube to glow extremely brightly. Had I not shut the radio off immediately after noticing this, the heavy overload would have destroyed the tube in no time flat.
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Old 05-04-2018, 03:50 PM
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All the tubes are glowing normally. It's just the way the photo turned out using my camera in low light mode. The brighter tubes are the horizontal output and damper tube. This set has a power transformer and all the tube filaments are in parallel.

I think the CT has enough life left to produce a decent picture. It gets about 1/3 of the way into the green region on my CRT tester. It just got to the edge of green then I did a 3 cycle restore with my CR-70. That's the gentle, current limited mode rather than the manual rejuvination blast mode.
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Old 05-04-2018, 08:31 PM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Jeffhs View Post
Bob, when I saw the picture of your Admiral TV in the first post of this thread, it reminded me of a 21" Admiral table model TV I had in the early 1970s. It was a trash find in my old neighborhood near Cleveland (much closer to the city than where I live now), and was in a white cabinet with the controls (volume, channel selector, vert. hold, et al.) under a trap door at the top of said cabinet. The set worked amazingly well for its age (since it did not have a UHF tuner, I would place it some time before 1964) with its original tubes, CRT (no brightener) and caps. (Bear in mind, this was decades before Videokarma and long before I knew that all old TVs made before about 1967 need to be recapped.) Unfortunately, I had to junk that set when I moved in 1972 (long story and OT); needless to say, I hated to part with it, especially since it seemed to be working so well. The only other TV I had at the time that worked better than the Admiral was a Zenith K-2739 23" console, which I also had to get rid of when I moved.

I'm glad your Admiral TV is working as well as it is. Hook it up to a DTV converter box and an antenna (or cable) and you should get an excellent picture; those old TVs were built to a level of quality we will never see again.

I noticed, however, in one of the pictures of your set's chassis, that two tubes, the horizontal output and the LV rectifier, were glowing much, much brighter than they should have, and I also did not realize the CRT in your set was so weak until I read the post a second time. Are those tubes glowing normally, or is one of them shorted? In my years of fiddling with electronics, I have only seen one tube glowing that brightly; that was in a Zenith radio I plan to restore one of these days. The pilot light had burned out, and was putting so much of a strain on the 35W4 rectifier tube that it was causing said tube to glow extremely brightly. Had I not shut the radio off immediately after noticing this, the heavy overload would have destroyed the tube in no time flat.
The set you're referring to is a 1958 model using 110 degree sweep and a transformer less chassis, just slightly different than the one mentioned.
They were decent, well performing sets.
On that line of sets the whole assembly slid out from the front.
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Old 05-08-2018, 07:24 AM
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Bob I have watched every video on your channel and have to say it's largely responsible for my renewed interest in vintage TVs, so thanks for that! I've moved to Europe from the US and have a very hard time finding anything familiar around these parts to restore (it's mostly newer German and Philips stuff). But this exact set just turned up at a thrift shop near me. I was planning to stop by and have a look "sometime", but I'm going to take it as a sign that you are working on the same set so tomorrow I'm off to buy it.

I really hope we'll get a video series on this one!
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Old 05-08-2018, 10:49 AM
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Good luck with it. I have recorded some footage but not sure when I'll edit and post it.

Here's how the CRT tests. Should produce a decent picture.


and a peek inside the HV box. Flyback looks to be in fine condition with not cracks in the insulation.


All the tubes have little sticky labels on them with the tube number. Odd since the original printed tube designators are quite legible. They all test good.


Replacing the electrolytics on the vertical output tube cathode bypass and boost circuit increased the height a bit.


I then removed a handful of vertically mounted caps from the PCB around the 6S4 vertical output tube. Seems like every one is a different manufacture and a few were leaky.

Replacing them got me full height.


After tweaking the height and linearity controls.


Next up - replacing these crispy crittters.
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Old 05-09-2018, 10:47 AM
dieseljeep dieseljeep is offline
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Good luck with it. I have recorded some footage but not sure when I'll edit and post it.

Here's how the CRT tests. Should produce a decent picture.


and a peek inside the HV box. Flyback looks to be in fine condition with not cracks in the insulation.


All the tubes have little sticky labels on them with the tube number. Odd since the original printed tube designators are quite legible. They all test good.


Replacing the electrolytics on the vertical output tube cathode bypass and boost circuit increased the height a bit.


I then removed a handful of vertically mounted caps from the PCB around the 6S4 vertical output tube. Seems like every one is a different manufacture and a few were leaky.

Replacing them got me full height.


After tweaking the height and linearity controls.


Next up - replacing these crispy crittters.
All the labeling on the tubes prove that the set owner used to take all the tubes to the drugstore to test them. There's not one original tube in the bunch. Someone spent a lot of money on tubes, they didn't need. I've seen a lot of that model that had mostly original tubes.
BTW, what circuit were those resistors used, It looks like they were replaced before.
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Old 05-09-2018, 10:59 AM
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I'm pretty sure they are the originals and although they look bad are not far off value.

They couple the boost voltage to the vertical output transformer and yoke.
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Old 05-09-2018, 12:43 PM
dieseljeep dieseljeep is offline
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I'm pretty sure they are the originals and although they look bad are not far off value.

They couple the boost voltage to the vertical output transformer and yoke.
By the way they look, it looks like they were in series.
I see the symbol next to the resistors show that there could be an alternate value used instead. I also shows that some versions used only one in the circuit, instead of two in parallel.
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