1951 Admiral model 5E22

       Analog Dial        

 
1951 Admiral 5E22, purchased at a hamfest in 2013 for 10 dollars.
 

 
This came from a Hamfest in Sellersville, PA. It was basically the only thing I bought that day. I didn't notice it at the time, but there were some nasty scratches right over the word "Admiral" at the bottom of the gold dial.

The cabinet also had scratches. Someone had waxed the cabinet and didn't get all the wax out. This made the scratches look
worse. There was also some white paint on the right side. It looked like it was from an impact. The knobs were pretty bad.

Hey, it is 62 years old. I have more scratches than that, and the radio is older than me! (barely)


 

 
Before and after. Eight capacitors, two resistors and a vacuum tube were replaced. When I was done... it didn't work!

 
Initially, the only sound the radio made was a very loud hum. After replacing the filter capacitors another problem arose.
While the set was warming up you could hear a radio station for about two seconds, then it would be drowned out with static.

The static wasn't coming from anything in the room, it seemed to be coming from inside the radio!

This really had me scratching my head as I checked almost everything, so I turned to those helpful guys on the Radio Board.
Among other advice, they told me the set might have Silver Mica Disease.
 


Silver Mica Disease
a.k.a. Silver Migration Disease, a.k.a. SMD

This is a new and better way for things to get old in the 21st Century.
 
In the 1940s, '50s and '60s silver mica capacitors were made by spraying silver onto a sheet of mica. This is an excellent way to make a high
quality capacitor if the silver and mica are sealed in plastic. However, if the silver is exposed to air it will oxidize. To make matters worse, in an electric current the silver will migrate, atom by atom across the mica, trying to reach the silver on the other side. When it does it will vaporize in a tiny electric arc. The process repeats over and over causing a steady static.
 

The capacitors in question are inside the IF transformers!
Are you kidding me??!
An IF "can" from a deceased radio was substituted. The radio came back to life. Dang, now I have to operate on the IF cans.

 
One of the IF (Intermediate Frequency) transformers.
Two capacitors, one for each coil, are contained on a single mica disk.
 
What is this stuff between the two capacitors?
It's Silver Mica Disease!
Each silver bridge was removed by scraping it off
with a small utility knife.

 
The case was polished for two hours with a polishing wheel in an electric drill, mounted in a vise. Almost every scratch was polished out.
 
The radio now works very well. When it was first turned on only a small amount of adjustment was needed. Apparently, there is enough silver left on the capacitors in the IF cans that adding new mica capacitors isn't necessary.
 

The knobs.
The knobs weren't good. The gold colored steel inserts had rusted.
After cleaning and painting.

 
I didn't know how I'd get the metal inserts out without damaging them. The knobs looked pretty cruddy, so I dropped them into a cup of hot water to soak before I took a toothbrush to them. I noticed a bubble of air came out. There was air behind the disks! I boiled a cup of water in the microwave and dumped it onto the knobs. The expanding air pressure popped both metal inserts out!

A day later it was off to an automotive store with Andrea to find a matching gold color. She spotted it right away. The metal disks were sanded and painted. AFTER I painted them I noticed we had purchased a high temp engine paint. The disks would have to "cure" at 200F for 7 hours. No problem, I put them on the radiator.


The next day we raked leaves. Andrea stopped me in the middle of raking and told me she had taken
the disks off the radiator and attached them to her boot. Then she lifted her pants leg to show me.
 
Why did she put them on her boot? Did she lose her mind?
Then I saw the raised rims on the disks. Those disks came with the boots! She does this crap to me all the time.
 

 
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