RCA 6T5 ca 1936

© Copyright Alexander D. Schapira, 2016 All rights reserved

I bought this RCA model 6T5 at an estate sale because I am partial to these old RCA sets, especially those with a magic green eye tube tuning indicator. This 6T5 appears to be the immediate predecessor of the RCA model 8T, is very similar in construction, and uses tubes that are a generation earlier than those of the 8T. To see my previous restoration of an 8T, look here.

I hope this will be of some interest to other RCA afficionados.

Click on any picture for a larger view.

As found, before restoration

The cabinet was grimy, but otherwise not too bad. The RCA logo and band decals were present, but there were no decals for the volume, tone or tuning controls.
The chassis and speaker were intact but filthy. Tube shields were missing, and the paper labels on the chassis rear were partially torn away.
As usual, the line cord was ratty and some visible wires, including those to the tube grid caps, were frayed.
The dial escutcheon was oxidized and corroded and the acetate window was very discolored.
Likewise, the eye tube bezel was also in poor shape. But the knobs were all present and original.
This is the label from inside the cabinet.
After removing the chassis, the need for a major cleaning was apparent.
But all the pieces seemed to be there.
The tuning capacitor was particularly grimy.
It would have to come out to be cleaned.
The chassis was very dirty, but there was no rust.
The underside was a little oily, but there was no rust. The original electrolytic capacitor cans showed signs of leakage. They would be left in place, for appearance, but disconnected and replaced electrically.

During restoration

The dial with translucent red and green scales was attached to a bracket with fly rivets. Of course, they broke off when I attempted to remove them.
The dial scale hid the screws attaching its bracket to the tuning capacitor. After the dial bracket was removed I stripped the yellowing paint from the inside of the dial bracket and gave it a coat of bright white paint.
The original finish of the tuning capacitor became visible. I also replaced the wire to the pilot lamp and cleaned the lamp socket.
The escutcheon, bezel, and dial cleaned up nicely. The acetate dial window is riveted to the escutcheon so I cleaned it in place as best I could.
The chassis cleaned up. After confirming that the major components were good, the cleanup continued.
The power transformer upper bell was stripped, primed and repainted. The aluminum cans were shined up a bit.
The paper capacitors were replaced as were a few of the dogbone resistors that were out of tolerence. The tone and volume controls and bandswitch were given the DeOxit treatment.
I sealed the bottom of the old electrolytics to prevent any additional leakage.
The electrolytics were replaced with modern units. I mounted them on terminal strips supported by the tabs on the original cans.
I added an X1/Y2 RF bypass capacitor to the AC line, and a 20 ohm, 10 watt series line resistor to reduce the transformer primary voltage by about 10 volts to about 112 VAC.
The tuning capacitor was reinstalled after cleaning and re-lubricating its gear-train.
The dial scale was reattached to the mounting bracket with small screws instead of fly-rivets.

All of the tubes were good except for the 42 output tube which was internally intermittent, and the 6G5 eye tube which was completely dead. I had replacements for both. The speaker, output transformer, and field coil were in perfect condition and just needed cleaning. The IF transformers and the antenna and oscillator coils ohm'd out correctly.

There were several frayed wires passing from the bottom of the chassis to the top through holes without grommets. I replaced the frayed wires and inserted a grommet where possible. I added a new line cord (and grommet where there had been none.) Surprisingly, the rubber mounts for the tuning capacitor were in perfect condition.

The internal resistor in the eye tube socket measured 100% high at 2 meg, but it was not possible to disassemble the eye tube socket to get access to the resistor without completely rewiring the eye tube cable. I left it alone and, as suggested by comments on the Antique Radio Forum, the eye tube functions properly with the 2 meg resistor.

Finally, I aligned the set and it performed well.

Next was the cabinet work.
A small piece of veneer was chipped out on the right side of the cabinet.
I replaced the missing veneer chip with a pretty close match.
The sharply curved veneer near the bottom front sides had cracked and lifted. I decided to simply press it down and reglue it.
The refinished right side view. The replaced veneer chip and raised, cracked veneer are barely visible.

After restoration

The cracked (but reglued) veneer is barely visible.
The refinished left side view.
There were no shields on the tubes as found, but I obtained some for originality.
Reattached the bottom mounting brackets after cleaning.
The speaker and chassis were reinstalled in the cabinet.
The original grill cloth was still good.
I did not strip or refinish the cabinet. A good cleaning and a little wax sufficed.
The remaining scars give it character.
Finally, I added an internal antenna consisting of one vertical loop around the inside of the cabinet. I also added new feet to the bottom of the cabinet to replaced the cracked and crumbling ones.
Complete

As noted above, I added an X1/Y2 RF bypass capacitor to the AC line, and a 20 ohm, 10 watt series line resistor to reduce the transformer primary voltage by about 10 volts to about 112 VAC. The radio draws about .5 amp during normal listening.
It was very satisfying bringing this set back to life and restoring a radio of a bygone era. I hope you enjoyed the story. Please feel free to contact me at w2ads@arrl.net

    -Al Schapira, W2ADS


Page last modified 04/21/2016