The PHILCO Phorum
1948 Magnavox "Berkeley" Just Acquired! - Printable Version

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RE: 1948 Magnavox "Berkeley" Just Acquired! - Mondial - 04-07-2022

If you are planning on playing this radio to any extent, I would at least recommend changing the coupling caps connected to the control grids of the 6L6G output tubes. They are marked 35 (.03 uF) and 43 (0.1 uF) on the schematic. Any leakage through these caps will throw off the DC bias of the 6L6's causing them to draw excessive current. This could cause a runaway condition which could take out the tubes, output transformer and eventually the power supply.

You can restuff these two with modern film caps if you want to retain the original appearance.

http://www.nostalgiaair.org/PagesByModel/334/M0010334.pdf

RE: 1948 Magnavox "Berkeley" Just Acquired! - mikethedruid - 04-07-2022

If you have not done so already, REPLACE THE POWER SUPPLY FILTER CONDENSERS !!! before you do anything else, before you turn it on again. They are the most likely to go, and if they do they can take the power transformer with them. Actually, I strongly suggest also replacing all the paper condensers, and checking all the resistors for out of spec ones and replace those too. Once done you will have a radio-phono which will be far more reliable, and probably only need a tube replaced now and then for the next half century.

RE: 1948 Magnavox "Berkeley" Just Acquired! - David - 04-07-2022

Thinking out loud maybe the reason the set looks so clean is somebody in the past restuffed the caps!

RE: 1948 Magnavox "Berkeley" Just Acquired! - captainclock1988 - 04-11-2022

I checked many of the caps and resistors, and it seems that the only caps that were bad were the across the line caps (there were 3 of them and they were all .02 µF 600V Micamold "Domino" style paper caps which were all leaking "wax" out of them, the rest of the paper caps measured fine yet using my Cornell-Dublier Capacitor Analyzer.

I agree with David that quite possibly this radio's cap's were restuffed sometime in the recent past as they tested little to no leakage, there was 2 paper caps that looked like they might of been later replacements, either that or they were sourced from a different source than the rest of the caps in this unit for some reason.