Admiral 30A15 restoration

[bandersen]

While restoring an Admiral 30A12, I ran into some issues and wasn't sure if was normal behavior or something wrong. So, since I have several other sets with the same chassis I decided to quickly restore another. I say quickly because I gain a lot of experience while working on that 30A12.

First, here's a look at it when I first brought it home. It was a cheap, local craigslist find.

I pulled the chassis out for transportation. Good thing too since all but one of the mounting bolts were gone.

This is a 10" model in Mahogany cabinet from 1948.


Ugh, that's going to take some work.


Nasty chassis that had been home to some rodentia.


The lower chassis had seen better days too.


Inside and back together. At least I have all the knobs and the CRT is good.

[bandersen]

Some months ago I started removing the rust with the thought that I could salvage the chassis.

HV cage turned out nice using electrolysis.


The power supply chassis and transformers turned out nice as well.




Ugh, that's nasty


Eventually, I gave up on the main chassis since the rust has eaten all the way through in areas. All is not lost though because I salvaged an identical 30A1 chassis from a "triple thrill" combo set.

No rust on this one

[bandersen]

I quickly recapped it in one night.


I later replaced the little selenium rectifier and axial electrolytics on the right side.


I encountered some crumbly rubber insulated wire that had to be replaced. I'd only seen this on late 30s - early 40s Philco radios before.


Rebuilding the power supply/audio amp was easily done by comparing it to another.


First signs of life


First stable image with some horrible horizontal linearity.


The culprit was an open damper resistor. The flyback looks miserable, but it's working just fine


That's better Very bright CRT in this set.

[bandersen]

Now what about the issues I encountered in my 30A12 ? This set has them too - weak audio and the IF traps don't peak. Also the 5U4 flashes over on power up.

I replaced the exposed mica caps in the IF cans. That help increase the sound and the coils now peak.


There are also power resistors lurking inside some IF cans that tend to drift upwards.


I added a CL-90 thermistor in series with the main power transformer primary to reduce the surge through the 5U4 rectifier on power up.

[bandersen]

Finally, an alignment and tweaks.


Here's the original hardboard back.




Easily one of the best pictures of my sets.

[ChrisW6ATV]

Very nice work!

[kvflyer]

Bob,

I absolutely hate you! No, seriously, that is a nice job and glad that you got it going easily as usual. Thanks for sharing your experience and please show us more!

[Reece]

Another Admirable job! Very sharp picture.

[bandersen]

Thanks. These 1st generation Admirals are a bit over engineered like an RCA 630TS. Stagger tuned IF, DC restoration and a dual power transformers for B+ and B++ so no need for massive bleeder resistors.

[kvflyer]

Originally Posted by bandersen

Finally, an alignment and tweaks.

Bob,

The geometry of the crosshatch and resolution are simply amazing! Lots of people have made the comment that Admiral sets were inexpensively designed and not up to the quality of the early RCA and Philco sets. Surely, this set isn't one of them.

Thanks!