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« Last post by SeanB on August 06, 2023, 01:31:45 PM »
These capacitors were in a little battery charger I just picked up. Germanium transistors, all point to point wiring, and these very elderly electrolytic capacitors. Of the 4 in there, in 2 series strings, only one comes back as possibly being a capacitor, the rest of them either are coming up as very bad quality diodes, or as a diode with 5000uF junction capacitance.
But then, as these capacitors are celebrating their reaching retirement age, for the two 5000uF 12V ones, or are already on retirement, for the 5000uF 6V ones, I would say they are doing well, despite the rubber seals being pretty much only for show.
Pics of the unit when it is cleaned up a little, but the pass transistor is an OC30, dated to roughly 1952, and, looking at the construction, made by Mullard in the UK. PNP, with a whole 1A4 collector current, and a breakdown voltage of 32V.
Updated to add in the whole PSU, after replacing the 2 capacitors, and doing a minor change to remove the non glowing and loose power indicator neon lamp. replaced with a 1000uF 63V and a 100uF 35V respectively, as those are what was in the box of capacitors I have, and came out first. Power on, and it actually works, and regulates reasonably well as well. Think it will get some use as a battery charger, as it does have current limiting, fixed with a pair of 10R resistors in parallel, and is adjustable from almost 0V to 12V. Not bad for a close to 65 year old piece of equipment, though safety is definitely something extra, no strain relief in mains, thin wire used there (predating Chinesium wire by around 5 decades it seems), and no ground on the metal chassis.
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