Just finished a recap on an AWA radiola B15 I got off ebay recently. Was trying to decide if the caps in it UCC "Hi Qual 100" Australian made should be changed or not. But I saw one looking like it oozed some wax. And the radio was not working that well, intermittent levels of gain in the RF-IF and some audio amp trouble. Well, after changing most of them out, the radio works much better. The only ones I didn't change was an IF stage cathode bypass (bypassing a 220 ohm resistor) and some caps in an audio feedback circuit (low impedance and no DC voltage across them).

I didn't change the electroytics, but in case they do go bad (shorted) on me, I added a fuse to the primary of the power transformer.

This radio looks a lot like an All American 5ive circuit, except for the power transformer. And it has a loopstick antenna, so no need for a longwire antenna.

My experience with UCC causes me to treat them with similar contempt as Micamold & paper caps. Some of the UCC's were in a plastic tube with wax sealant & a lot of them were papers.

I would be suspicious of the bypass caps. I am finding quite a few transistor car radios with volume loss in particular, caused by electrolytics drying out & developing high resistance (lower capacity actually).

Marc

I decided to replace the filter electroytics. Had to hunt down a reasonable replacement for the first filter cap, as it's tied directly to the tube rectifier cathode. 22μF at 450VDC. Too much capacitence will shorten this tube's life. The 2nd cap, behind a 4.7K resistor can be bigger and not hurt the tube. Had a 82μF at 400VDC handy. The old caps seemed to get a little warm, which means that there's some leakage inside them. I left the old caps above deck, but they are no longer connected.

Yes, my UCC caps were in plastic tubes with some sort of brownish sealent at the ends. And just like their wax paper American cousins, they went bad.

Found that a 100pF cap "Simplex MS" in the plate of the 6AV6 audio driver stage was making noise. It had about 65V across it. Also changed the detector filter cap, also a 100pF "Simplex MS" cap. These were brown rectangular caps. And replaced the last of the UCC wax caps. Radio seems to be behaving well now...

I used to think that the very similar-looking UCC "Di-Pol 100" caps were polyester and therefore above suspicion, but I pulled a dud apart recently and they're just oiled paper and foil. Don't be fooled by the name! That said, most of them are still OK.

Hi I've actually got 4 of these, 2 AWA's and 2 Westinghouse Wide-Fi's (Identical except for the name) The later ones have mustard caps instead of paper, I've replaced the electrolytics in all of mine bar one I haven't got around to yet, and all of those UCC's except in one of them I only replaced the ones which handle large voltage, they are good dependable radio's. One of mine has no knobs, so I am looking for 3 of those! They are a great little radio. I'm slowly replacing the cords with 3 wire ones to earth the chassis, It's just a matter of filing out the cord clamp to accommodate the thicker cord.