08/19/2026
Cosmetic refurbishing and electronic restoration of 1931 DeForest model "Encore" Model Type 500 chassis radio.
I received an inquiry from Sommer B. who wants me to look at her heirloom radio that has been with the family for over 60 years. She sent me a few photos of the radio but I cannot find the model number anywhere. I need to look at the schematic before I can assess the radio and give her my opinion. There is a label of Jones and Cross Ltd. Edmonton where the radio was purchased. Later Sommer confirmed that the radio was originally bought in Edmonton by the grand parents of his hubby Craig, and was brought here to Vancouver, BC. They are wondering if the cabinet can be refurbished for decoration or she should be electronically restored as well. I immediately advised her that she deserved a full restoration both cosmetically and electronically because of the rich family history.
The 1st few photos show the state she was in. Speaker cloth was ripped. The cabinet was in bare wood after someone in their family stripped the paint finish. All wood k***s are there.
The radio was built like a tank and weights a ton. The overkill power transformer alone probably weights 8 - 10 lbs. The chassis has flanges on both sides and slide inside 2 U-shape channels and cushioned by some foam which has deteriorated over the years.
After some cleaning and polishing, the metal parts shine again like new. A 8uf electrolytic condenser has red copper can which is very unusual when you consider the cost of copper. Its has the value 8 uf 450 v engraved on top instead of printing. There are 6 vacuum tubes: UY235, UY224,UY235, UY224, UY247 and UY280.
These are tubes used in most 1920's sets. Some are the beautiful hot air balloon glass envelop type. Both UY224 are tested DEAD unfortunately. Luckily I have two 24A which I can replace with. UY224, 224, 24, 24A are actually the same tube just marked for different usage. The 24A is an improved version of the original UY224 with faster warm up time and treated plate.
The radio has only 2 electrolytic capacitors being the Red copper one and the paper tube one. They are replaced with 10 uf-450v modern ones about 1/15 of the size. All other capacitors replaced. Some "dog bone" resistors have drifted beyond 15% and replaced accordingly. The output transformer is found dangling and not fastened down to the chassis.
The good thing about working on 1920s to early 1930s radio is the generous space under the chassis that make it easier to work, but the tough part is to chase the wiring and ID the parts. Engineers designed things differently 95 years ago. American tends to use thick cotton jacket wires with oversize gauge conductors while German radios have thinner gauge wires just enough to carry the current according to the German engineering.
Hazeltine Corp. was an American communications company since 1924 and has gone through different changes and ownership. I will leave it up to you to research its history which is quite interesting. A great deal of time has been spent on tracing the wiring and identifying the resistors and capacitors. A few "dog bone" resistors have drifted in values and replaced with new ones nearly 1/20th of their size.
After the recap job has been completed, I have to pull the 8" field coil speaker from the cabinet to facilitate test run. The speaker is in excellent condition even has a shroud to protect the paper cone which is rarely seen. Since the speaker is out of the cabinet, its a good chance to work on the cabinet and speaker cloth at same time. The cabinet is so nicely stripped, all I have to do is to sand it down so slightly with 800 grit sand paper and apply a very thin coat of "traditional cherry" stain. It soaks up the stain like a sponge. After a couple of days of drying, 2 -3 coats of high gloss clear varnish is applied to the k***s, copper bezel plate and re attached. Four rubber feet also installed. I have picked a bright gold color cloth with floral design for speaker grille cloth. It is stretched and attached to the mounting board with 5 minute Epoxy. The last photo shows the final product. This old lady retains her original beauty like 95 years ago.
Radios of this era are always thirsty for strong radio signal. If you are old enough, you may remember seeing the external antennae on top of buildings everywhere. They could look like a long copper wire suspended by ceramic insulators at both ends, or wires wound around a cross shape wood frame and look like a big spider web. With the improved transmitting power of radio stations, we can do with just a long piece of spread out wire. As a trick for radio technicians, I stapled a wire on the underside of the cabinet to act as antenna. It looks like the heating element of an oven. I choose to do this as added value to the radio.
After hooking up the AC draw current meter, the power is gradually increased from 85 vac with an Variac. Radios this era do take much longer warm up time due to the lower 2.5 V heater voltage. The AC current draw is around 0.6 Amp which is normal. I was testing the radio with a short external hooked up to make sure she has got enough oomph to jump start. After a few stretching and yawning, she comes to life. The volume control controls how much radio wave is grounding, the less grounding the louder she sounds.
All plate voltages measured to be acceptable and the power consumption holds steady. I hooked up a signal generator and inject a 600 KC and then a 1300 KC signal and adjust the 3 padding condensers to obtain maximum output. The radios is quite powerful even with just the DIY built in antenna wire.
Now I am ready to slide the heavy chassis back to the cabinet. I cut up couple of rubber strips that I cut from the inner tube of truck tire to 1" wide by 5" long and wrap them along the flanges on both sides of the chassis for cushioning.
The radio is ready to come home to Sommer B family where she has sit mute for the last 60 odd years. I hope Granny is ecstatic to see her childhood radio back to life again. I am grateful to have the chance of working on this beautiful heirloom radio.
The satisfaction is priceless.
Kim finally came to pick up her childhood company, except this time she is no mute, she sings beautifully. I just realized that Kim stripped the re painted (literally) finish herself when she was a teenager. She has done such fantastic job that makes it easy for me to refurbish.
See last photo of another satisfying customer with her beloved 95 year old resurrected antique radio.