Identify these capacitors. - UK Vintage Radio Repair and Restoration Discussion Forum

G6Tanuki · 21st Nov 2021, 6:05 pm

Doing a 'rolling rebuild' of my R209 receiver I've now got to the IF modules. Which, being unpluggable-from-the-radio-chassis makes them so much easier to work on.

Inside, the HT- and Screen-decouplers are these strange 0.01uF 350VW capacitors with a translucent plastic encapsulation.

I've never come across these before. Close examination suggests they are a form of waxed-paper capacitor - the pink label is definitely paper and I can see what appears to be paper-and-foil at a couple of places at the end terminations.

I'm replacing them with nice yellow MKT capacitors, but would be intrigued about your collective opinions on what might be inside these old capacitors. What does "Cat B" mean?

joebog1 · 21st Nov 2021, 9:51 pm

They look like polystyrene to me, but a maker?? no idea. Do they leak? a good polystyrene that hasnt been overheated during soldering should last almost forever.

G6Tanuki · 22nd Nov 2021, 12:27 pm

I havebt yet wired one of them in series with a neon across 350V - that comes later this evening! Will report back on whether the neon flashes or not.

21st Nov 2021, 6:05 pm	#1
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,014	Identify these capacitors. Doing a 'rolling rebuild' of my R209 receiver I've now got to the IF modules. Which, being unpluggable-from-the-radio-chassis makes them so much easier to work on. Inside, the HT- and Screen-decouplers are these strange 0.01uF 350VW capacitors with a translucent plastic encapsulation. I've never come across these before. Close examination suggests they are a form of waxed-paper capacitor - the pink label is definitely paper and I can see what appears to be paper-and-foil at a couple of places at the end terminations. I'm replacing them with nice yellow MKT capacitors, but would be intrigued about your collective opinions on what might be inside these old capacitors. What does "Cat B" mean? Attached Thumbnails __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

21st Nov 2021, 9:51 pm	#2
joebog1 Banned Join Date: Jun 2015 Location: Mareeba, North Queensland, Australia Posts: 2,704	Re: Identify these capacitors. They look like polystyrene to me, but a maker?? no idea. Do they leak? a good polystyrene that hasnt been overheated during soldering should last almost forever.

22nd Nov 2021, 12:27 pm	#3
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,014	Re: Identify these capacitors. I havebt yet wired one of them in series with a neon across 350V - that comes later this evening! Will report back on whether the neon flashes or not. __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.