Odd part question

[David Schuh]

While restoring my Majestic radio I came across 2 of these odd parts. It looks like a tiny aluminum pot held in by a spring clip. On the schematic I can’t tell if its a battery or electrolytic capacitor. What is it?

[Dan Walker]

It sounds like you have two bias cells… I have Rogers and Marconi radios that use them. They are 1.5 volts.sometimes you can check them with an ohmmeter and you may get a small reading. The radio will probably work without them.. I have used a 1.5 volt hearing aid battery in place of them and it does work.. Just make sure the polarity is correct
Probably otheres on the forum can shed more light on this topic

[phil]

Gerry did an article about bias cells, you might have to look through past newsletters to find it. I think there was something under resources in the old forum but since it has been moved to this new format I couldn’t seem to locate those articles.

[David Schuh]

thanks for your replys. I’ve attached a picture of the part. I’ll sift through the newsletters for the article.

[David Schuh]

Gerry mentions the bias cells in the may/june 2009 newsletter. I’ll pop a couple of battery’s in their replacement.

[Bob Masse]

Hi! David
https://members.shaw.ca/pacifictv1/gbcells.jpg
Here is some info.

I recall reading somewhere that they can be rejuvenated by boiling a little distilled water, then turning off the heat, and dropping the cells in. The cup of the cell is zinc, the cap is carbon, and it’s sealed with a rubber disk, The rubber deteriorates with time and cracks. In hot water the air inside the cell expands,and should cause bubbling in the water. Then when the water cools some water is drawn into the cell by vacuum action. Let the water soak in for a while and then test the cell for voltage. From what I’ve read it should be 1 to 1 1/2 volts. If not the cell did not rejuvenate. Then the area of the sealing disc will have to be sealed with some type of glue or silicone.
Here is more rejuvenation info:
https://www.philcorepairbench.com/biascell.htm
Bob Masse

[David Schuh]

I used modern flat 1.5v cells as a replacement. I may try the rejuvenation trick later. Quite a good reference article. tnx.

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