got around to replacing the old can caps in my RCA TV
 

I recapped this TV
http://www.wa2ise.com/radios/rca21t8395.jpg some years ago, except I didn't do the filter electrolytics. http://www.wa2ise.com/radios/rcatvback.jpg I had figured that they are not getting warm, so they should be okay, but I decided that I ought to recap them anyway. I hacksawed the old cans off near their bottoms, so I could make use of their terminals to attach the new caps, and I wouldn't have to undo the wiring.

I found in my stash replacements, two 100uF@450V, two 22uF@450, and a 10uF@400V. Pretty much direct replacement values. I put the 100's up top, drillling holes thru the old caps' terminal block to pass lead wires. There was also a 20uF@50V, which was used as a cathode bypass for the audio output tube, but I left that out. There's plenty of sound output without it, and I'd get some cathode feedback to help the fidelity of the sound. Anyway, I decided to use the long lead wire (the audio output tube was on the other side of the chassis) to become the negative lead of the first filter cap, the one right on the 5U4. And I found where the B+ winding centertap of the power transformer went to chassis ground, and connected this lead wire there. This new first filter cap's negative side I locally isolated from the chassis where the old cap was grounded. I wanted to confine the cap ripple to the centertap, so it wouldn't contaminate the chassis ground. Seemed to work, as I don't hear any hum now (I did before). I also do this with tube hifi audio amps. The other cap negatives I grounded locally. The CRT picture looks a bit better (though I still see some horizontal sweep irregularities). The set does seem to be preforming better, less noise from the tuner and IF strip, and clearer sound. Though I did find a 270 ohm resistor (the audio output tube cathode resistor) that drifted high, so I replaced it. Which should also make the sound better.

Right now I'm watching on this TV my local PBS station (channel 13) show reruns of Ed Sullivan when he had the Beatles, Stones and other British Invasion groups on. Likely the same footage this TV "saw" back in the day...

I was also able to reduce some horiz related bars in the picture. I could vary it with the "horiz drive" trimmer cap, but I needed another 68pF cap across it to get it down to a decent level. The trimmer is rated for 10-100pF, so it looks like it's at around 170pF. I used a 4KV cap as I don't want this cap to flash over and do bad things to the horiz circuit....

Also tried to improve the focus on the CRT. This set is not adjustable, but the datasheet for the CRT, a 21CEP4, says it can be between 0 to 400V. Found it was slightly better at around 90V, vs the fixed 255V.