1949 Silvertone 9116 7" Leatherette
 

I picked one of these up. On the schematic I pictured and in the circle, there were originally 2 qty .0005 (500pf) @ 6K tubular caps. They were apparently replaced with 2 qty .0005@ 10K tubular caps. Should they be replaced with 6 or 10K? And do they have to be tubular or can I use ceramic in this location?

Im not sure when I'll get started on this but thought I'd line up the parts. If I end out with more questions I'll add them to this post. thanks!

Either voltage rating would work. Ceramic caps are common there.

Just radios has them in 6000v tubular.

Yes, I noticed justradios has 6K ones but thank you for telling me. If I can use ceramic they might be cheaper.

I did forget to ask what % tolerance would I need?

I have used both, and both work fine. But I do like the tubular better. No reason why tho

The voltage rating on a capacitor is the max voltage you can safely apply to it without causing damage. You can replace a cap with a higher voltage unit without causing harm...Though on some electrolytics if you rate them too high (like say installing a 450V cap where a 150V was) they may not age as well as they should years down the road (plus higher voltage costs more especially in lytics).

Ceramic is fine for filtering the HV supply however if that set is electrostatic deflection (7JP4 CRT and a few other CRTs) the KV rated caps that couple the signal from the H and V scan circuits to the deflection plates should be film type. Ceramic caps can sort of work for sweep coupling but you either have to increase the capacitance by ~2x (ceramics tend to lose capacitance at high voltage), or live with shrunken and or non-linear sweep.

Yep, it has a 7JP4. From the last post it sounds like I will use films. Thanks everyone! I'll be back if I have more questions when I start working on it.

I got a full schematic for the set instead of using what is glued onto the set. Lucky me, there are 4 .0005@6K and 2 .005@6K caps. 2 of them (.0005's) I am picturing as ive never seen caps like these. What style of cap are these and are they reliable or do they also need to be replaced? (the 2 fat brown objects) Going by the schematic they are not original to the set.

Those are called 'doorknob' caps, typically rated around 20 KV. Used for filtering HV in electromagnetic-deflection sets. You'd probably want to replace them for aestheics. If they're good, they might come in handy in future project(s).

They are also used in some electrostatic sets IIRC the Hallicrafters and or National brand sets.

If the value is right they could potentially be left in. These capacitors are fairly reliable but once in a while, you will find one shorted. I always look upon them with suspicious optimism. :D

Hmmm, interesting. I just looked up doorknobs on ebay and saw a bunch on there. With the price of the replacements if they test ok I might leave them in, at least until Im sure the set is OK. There has been a lot of work done on this set in the past which none of us like to see on any tv or radio. Thanks again guys! Im sure i'll be back with more questions.

Im finally getting started on this and have the electros and regular caps on hand. The photofact is 97-16 and it is different than the Sentinels and a couple similar style others i found online.

Anyway, it was blessed with several Micamold caps. i have rarely seen any of them and they were always real small values and i left them in, but this one has 7000pf, 5000, 750, 360, 330, 270, 220, 100pf sizes.

Question #1. Im assuming the large, over 1000pf sizes will be paper inside. Should/can they be replaced with paper?

#2. The ones under 1000pf replaced with mica?

I have a feeling I'll have more questions as I already found some parallel resistors added to shorted resistors in the vertical, but I'll see if I can figure it all out first before i ask about those. I can add a pic or 2 of the schematic or chassis if needed.

Micas under 1000pF usually are good and can be kept in use, but you should order replacements for the ones in the horizontal and vertical stages since those are put under a lot of stress. Leave ones in the RF and IF stages alone unless you can prove failure...they are usually fine, and changing them can mess up the alignment. They still make micas so replace mica with mica.

Caps 1000 and up are often paper, replace them with film caps the same as you should with old paper caps. They still do make paper caps but they are over priced audiophool junk... better to replace all old paper types with cheaper more reliable modern film caps.

Thanks! I think there were 4 in the vertical area. Unsure on the horizontal. They littered the chassis with micamolds.

Im sorry, I meant replace them with film, not paper. i was typing fast but thinking slowly before leaving today. I ordered and got the film caps from mouser for the paper ones, panasonics I see talked well about, but did not order any to replace the micamolds but Im sure I have some of them on hand here, the films anyway. I will have to order mica's to replace the lower values, if needed.