Zenith ch 17Z22Q nonpolar cap issue

[ha1156w]

I am finally a couple of years on catching up on projects set aside. In this case it's my Zenith 17Z22Q chassis 21" B/W tabletop. I've recapped the chassis and ran across a strange one - There's a nonpolar cap 10uf 400V (C3 in the Sam's) strapped to the chassis right next to the HOT socket. It appears that sometime in the stone age it arced between the cap and the HOT socket, through the plastic "ring" Around the socket on the underside. Cap has a hole burned in it at about the 4 o'clock position close to the chassis, hidden from view until removal. What would have caused it in the first place? I assume they knew what they were doing when they riveted that cap so closely to the tube socket. Factory goof?

I've had a bit of trouble sourcing a bipolar cap in that voltage. Anyone I can pick at? My usual vendors aren't stocking anything that high, not Mouser, not DigiSneeze, etc. Who has something to replace it?

[marty59]

Unfortunately, you do not have many choices here. I've mentioned in other posts about my Zenith 17Z22Q with this cap. I imagine you have the schematic as this cap is between the B+ and B+ Boost and floats between those potentials. Even though as mentioned some may cringe but you can put two 20-22uf caps in series with each other with the ground leads tied together so you're connecting the "positives" to the voltage sources. The Howard Sams parts list even mentions doing this for replacement. I removed the old cap from it's chassis mouinted strap and shaped it so the replacements fit and hooked the leads to use for tie points as the original.

I have logged some hours on my set and those caps stay cool and work as intended. Most other models of sets (and Zenith's) from this timeframe usually used a boost capacitor connected from the source to ground.

My cap still "looked" good as removed but yours I'm sure must have broken down. I really don't think of it as being a factory goof, but the components are kinda' tight in that area....