Admiral 30A12 restoration

[bandersen]

This 10" B&W Admiral set from 1948 just showed up on my door step a few days ago and I thought I'd poke around with it while I wait for lacquer to cure on my GE cabinet.

it was generously donated by an online friend along with some test equipment a GE radio and a whole box of Sams (radio only).






It's dirty, missing the back, channel knob is wrong and the cabinet is a little rough, but otherwise it's all there.


Luckily, I have a spare channel knob handy and the screen area cleaned up surprisingly well with a little Howars RAF, steel wool and Windex

[bandersen]

Some of you may have noticed it's the same set as my avatar. True, but this has the original finish while my other set does not. When I received it, it had been stripped down and clear coated with polyurethane. I stripped all that gunk off and refinished it with toner lacquer. I had a hard time finding good photos of this set and guessed a little about the proper color.
I can clearly see now I didn't get it quite right


Anyway, continuing on with this set, the CRT tests very good I also discovered almost every tube appears to be the original Admiral and I see little sign of repairs.


Filthy for sure, but not much rust. The fly looks OK and it's fused.

[bandersen]

I now have five of these 30A1 series Admiral sets but have never actually seen one work as none of mine have been restored yet.
So I decided to try a slow, control power up. First I pull the rectifiers out, powered it up and all the filaments lit up


Next, I reinstalled the rectifiers, put a 150W bulb in series and slowly powered it up with a variac. Around 100 VAC I heard a hum out of the speaker.
I took the bulb out and increase to 115 VAC and thought I hard a little HV crackle but no glow in the CRT face. A little tweak of the fine tuning got me nice, loud clear sound


A little tweak of the ion trap magnet got me a very bright, crisp raster


It's trying hard to lock, but can't quite make it. I went around to the back and adjust the horizontal oscillator and finally, got a lock.
I then had to crank the height up all the way to get this image.

Oddly, I could get channels 2 and 6 to work, but not 3, 4 or 5. I hope it's just dirty contacts.

Not bad for 65 year old parts


Now I did smell all sorts of aromas emanating from the set - burning dust, ozone, hot wax and cooked resistor. So I ceased my testing,

A little later I pulled the chassis for a closer look.




One casualty found so far.




After a little cleaning, it's starting to look more respectable.

[DavGoodlin]

A low-hours set and a half-watt resistor is all you need to worry about frying, then you have a rare set that will get sound and picture.
I would not try it with any of my RCAs, and probably not a Philco or Sylvania either.
Only Admirals & Zeniths seem to be able to come to life with that minor intervention.

[bandersen]

I started testing a few tubes and a few are weak have secondary emission or both. I think only three tubes are not Admiral branded - 5U4, 1B3 and 6Y6 audio output.
Now I don't expect to keep running this set on all those original caps. I just find it interesting to slowly replace parts methodically for a change rather than shotgun them all.

[Sandy G]

They MUST have made a blue zillion of these, & the 7" sets..The story on MY 1911A1 7" Bakelite set was that the guy who owned the theatre in town got it, He & his pals would take it up on Dump Hill, the highest place in town, & could SOMETIMES pick up WSB or WAGA out of Atlanta..We didn't have TV around here til late 1953 or '54..

[bandersen]

I don't know about these 30A12 sets. It's one of the first models they sold and I don't see many around.
The other versions with the "X" on the speaker grille like this seem to be a lot more common.

[bandersen]

I replaced the fried resistor, cleaned the tuner, replaced a weak 6SN7 vertical oscillator tube and made a crude repair to the broken fuse holder.

These old Admiral sets used and odd fuse size. It's the same diameter as modern fuses but they were shorter.
Someone jammed a full sized fuse in there and broke the mounting. I'd like to find a source of these shorter fuses, but I don't think they are made anymore.


This crumbling power resistor still tests OK, but I plan on replacing it.


Those tweaks definitely helped. I now get clear reception through channel 3 and better vertical height.
I just realized the image is much too wide though. This set has a rectangular mask and a lot of this image will get cut off.

[radiotvnut]

Nice find and not bad performance for a 65 year old set running on old parts. The chassis looks similar to the one that's in my '49 combo; which, I need to get going.

[W4rtc]

Hi Bob
What is the physical size and what current rating of the fuse?
Joe

[bandersen]

250mA - 1" long 1/4" in diameter. I believe that's an 8AG type and Digi-key has them. $1.72 each - ouch.

I pulled and tested all the tubes. Almost all are Admiral. The rest are Sylvania. All test very good and nearly the same. That seems to confirm my hunch it's a low hours set.

[DavGoodlin]

Nice when that happens. I wonder if the 6J6 has a different origination due to the hex around the tube numbers.

[Phil Nelson]

Originally Posted by bandersen

I had a hard time finding good photos of this set and guessed a little about the proper color. I can clearly see now I didn't get it quite right

The one on the left may have faded and yellowed, like many other old cabinets. I would look in the back or the inside for a finished area that wasn't exposed to light. That would give you a better idea what its original color was. Edges of that nature may be exposed when you remove safety glass bezels or speaker boards, for instance.

Phil Nelson

[bandersen]

Thanks for the tip. I started measuring the old paper caps and wasn't too surprised that every single one is leaky to varying degrees. The resistors aren't too bad and the electrolytics seem to have some life left.

[bandersen]

Originally, I figured I'd restore this set a section at a time and see steady improvement. The reality though is that the longer I run it on those old parts the more problems pop up. Lost sound, lost vertical sync & height, etc.

Even one of the tubes that tested great developed shorts. Also, I tested about a dozen paper and electrolytic caps and all are leaky to varying degrees.

So, I think I'll stick with my usual approach of shotgunning all the caps right away.


Recapped power supply/amp chassis.


I'm about 75% done with the main chassis too.


Sync is pretty solid now but the sound is weak and the picture isn't as bright as I'd expect.
Also, the picture is too wide considering this set has a rectangular rather than "double D" mask.
Perhaps both those issues are related to low HV so I decide to poke around in the HV cage. Very easy to do on these sets. Just remove three screws and the side comes off.


There I discovered the 1M resistor inline with the second anode as about 70% high!