Absolute beginner (in terms of vacuum tubes/tvs) and I will need many tips…

[Electronic M]

Originally Posted by Madeline12

Was unaware about the tidbit regarding the paper caps… VERY happy that you shared that. I’ve been hunting down some of the electrolytics stated in already… seems some are pretty tough to find already (10uf 600V… yeesh). Still looking though. Thank you!

This isn't a favorite practice among restorers but is a solution Dumont used in its RA-103 to get a voltage not offered. When you put 2 electrolytic caps of the same value in series the effective working voltage is the sum of the caps, and the effective capacitance is half of an individual caps value (it gets much more complex if the caps are different values).

What I would do is put two 22uF caps rated in the 350V-450V range in series. Electrolytic caps have polarity like batteries (and will explode and or smoke if connected backwards), and when placed in series you want to connect the positive of one cap to the negative of the other. Additionally since electrolytics are rarely perfectly identical even from the same maker there's a tendency for the voltage to split unevenly...To prevent this get two 470K ohm 1W resistors and place a resistor in parallel with each cap. The loading of the resistors will be negligible on the circuit but enough to equalize voltage across each cap....This is basically the exact circuit used for the first lytic off the rectifier in the Dumont RA-103.

[Electronic M]

The service adjustments with the threaded shafts are tuned inductors or tuned transformers...the tuning is magnetic permeability tuning. The screw threads move a small slug of ferrite or copper in and out of the core of the coil. Unless they are physically stuck (and you need to adjust one for some reason) and can't move they don't require or benefit from cleaning. Also if the tuned coil is not in the horizontal circuit DON'T turn it at all....Most tuned coils/transformers are in the tuner and IF circuits. The tuner and IF stages require precise electrical alignment for the set to function...This alignment 97% of the time is still fine as it sits today. If you disturb any tuner or video IF adjustments you will have to buy a lot of very expensive equipment and spend a large amount of time learning the borderline dark art of television alignment.

TV chassis can only have voltage on them if plugged in to the wall, and that usually only goes for hot chassis sets. The capacitors can store voltage, the lytics and CRT are the only ones that can hold it long enough to get you. The lytics typically self discharge within a minute (you can take a clip lead connect one end to chassis and touch the other end to the positive terminals to ensure discharge if you're worried), but the CRT can hold it's charge for days....The good thing about the CRT is it can only store an amount of charge that is close to the worst static charge you can get shuffling feet on carpet and touching a doorknob, but it's still bad enough to trigger reflexes (and what you elbow on reflex can be sharp...ask me how I know) so if you need to poke around in the HV cage or remove the CRT discharging the CRT is strongly recommended. To do so connect an end of a clip lead to chassis, connect the other end to one end of a 1M ohm resistor, connect the other end of the resistor to the metal blade of a well insulated screwdriver, then holding the driver by the insulated plastic handle slide the blade under the HV suction cup connector (some 50s sets don't have a suction cup and just leave the metal connector exposed) on the side of the CRT and hold it to the metal for 30 seconds.
You can do without the resistor and connect the clip lead directly to the screwdriver but that allows a phenomenon in CRTs known as dielectric recovery where a fair portion of the charge magically reappears after a few seconds or minutes.... I've been bit by it and uttered more swear words because of it than I can remember.

[Madeline12]

Originally Posted by Yamamaya42

DeoxIT D5,, it ain't cheap, but it really works well!

I actually do have some for my solid state repairs, so I will be applying that here as well

Originally Posted by Electronic M

The service adjustments with the threaded shafts are tuned inductors or tuned transformers...the tuning is magnetic permeability tuning. The screw threads move a small slug of ferrite or copper in and out of the core of the coil. Unless they are physically stuck (and you need to adjust one for some reason) and can't move they don't require or benefit from cleaning. Also if the tuned coil is not in the horizontal circuit DON'T turn it at all....Most tuned coils/transformers are in the tuner and IF circuits. The tuner and IF stages require precise electrical alignment for the set to function...This alignment 97% of the time is still fine as it sits today. If you disturb any tuner or video IF adjustments you will have to buy a lot of very expensive equipment and spend a large amount of time learning the borderline dark art of television alignment.

TV chassis can only have voltage on them if plugged in to the wall, and that usually only goes for hot chassis sets. The capacitors can store voltage, the lytics and CRT are the only ones that can hold it long enough to get you. The lytics typically self discharge within a minute (you can take a clip lead connect one end to chassis and touch the other end to the positive terminals to ensure discharge if you're worried), but the CRT can hold it's charge for days....The good thing about the CRT is it can only store an amount of charge that is close to the worst static charge you can get shuffling feet on carpet and touching a doorknob, but it's still bad enough to trigger reflexes (and what you elbow on reflex can be sharp...ask me how I know) so if you need to poke around in the HV cage or remove the CRT discharging the CRT is strongly recommended. To do so connect an end of a clip lead to chassis, connect the other end to one end of a 1M ohm resistor, connect the other end of the resistor to the metal blade of a well insulated screwdriver, then holding the driver by the insulated plastic handle slide the blade under the HV suction cup connector (some 50s sets don't have a suction cup and just leave the metal connector exposed) on the side of the CRT and hold it to the metal for 30 seconds.
You can do without the resistor and connect the clip lead directly to the screwdriver but that allows a phenomenon in CRTs known as dielectric recovery where a fair portion of the charge magically reappears after a few seconds or minutes.... I've been bit by it and uttered more swear words because of it than I can remember.

Good to know! I will be watching out for that… rather not drop any more money if I can help it

[Chris K]

I'm a little more advanced but not much! I've managed to get a couple dozen of these postwar sets up and functioning pretty well. I love most the TVs from 1947-1955 with RCA as a favorite brand. All sound advice here. I'll add a couple from a beginner's perspective. Wait until the real experts here chime in and point out any mistakes I've made before you employ my suggestions as technique:

1. All of the warnings regarding hot chassis, high voltage often in the 10Kv range and above are the first and foremost thing that needs to be respected. One thing I've heard is the HV anode can really hurt but the voltages in the flyback can kill you. High capacitance, new and old, electrolytic caps can hold charge for a while, especially ones in the power section. They don't hurt...they just give an uncomfortable buzz.

2. Don't buy cheap, hard to believe how many you can get, electrolytic and film capacitor "sets" from China. When I searched Amazon, I was astounded I could get 100uf electrolytic filter caps at a little more than a dollar per cap, so I bought a ton of them. They caused more issues than they were worth. I could not run down a horizontal instability issue in an 8" RCA PT-8-3034. Turns out it was the main "Uxell" filter cap in the power supply that created all the issues. Don't buy cheap stuff. You can use these to test something...just as a tack in but don't rely on them for service use and if you have a problem, suspect them first.

3. If you buy old analytic equipment, be sure it's working well and you can trust the results you are getting. Again, a lesson I learned in the TV school of hard knocks.

4. Don't replace everything first and then test. Start with the power supply. I have a dim bulb setup and I start running the TV with a 60 watt bulb for about 15-20 minutes and then progress through 100, 150, 200, 250 and 300 watts. REMOVE the lead off the horizontal output tube until you get to the higher wattage bulbs. The horizontal oscillator will not start until it gets a certain voltage and the lack of oscillation can drive excess voltage through the Horiz. Output Tube (HOT) and fry it. If I suspect the main power electrolytic caps are bad and can't be reformed or test shorted, I'll replace them before first power up. A shorted electrolytic in this section can fry the power transformer. Ask me how I know that!

5. Service Power, Sweep and get a raster...then go for a picture. Check the TV function often if you can. Don't get carried away and replace a dozen caps and resistors to find you don't have a working TV. You won't know where to start to run it down. If you test...replace...test etc. it's the easiest way to be sure you don't create issues rather than solve them. Again, ask me how I know that!

6. Find the expert restorers on YouTube and watch their videos. My go to are Bandersentv (he posted in your thread) and Shango66 but there are many others.

7. Test the CRT before you do anything else. A dead and rare CRT is usually a showstopper unless there's a way to modify the circuit and substitute it with another type CRT.

I'll probably think of more from the rookie mistake file I have. The experts here sometimes forget how stupid the novices are! Not their fault. When you talk like you know what you're doing they assume you know what you're doing!

[JohnCT]

Originally Posted by Chris K

7. Test the CRT before you do anything else. A dead and rare CRT is usually a showstopper unless there's a way to modify the circuit and substitute it with another type CRT.

There are three other "hard parts" (auto transmission reference) in a TV that can be showstoppers besides the picture tube - flyback/HV transformer, deflection yoke, and power transformer. The vertical output transformer can also be an itch but those are easier to fudge with a similar but not exact replacement.

Your idea of rebuilding the power supply is a good one (I'd disconnect the chassis and use a dummy load). This will at least eliminate the power trans. Getting the sweep up next is also a good idea. If you can get HV, then fire the parts cannon at it.

John

[Electronic M]

Some recapping advice: never go lower on voltage rating (you can go higher, although more than double typically isn't recommended), but never lower. There are pre-war and post-war standard capacitance values. Both coexisted in the 50s-70s but the pre-war values are either NLA or stupid expensive. Prewar standard capacitance uF values were 10, 20, 30, 40, 50, 60, 70, 80, post-war values are 10, 22, 33, 39, 47, 56, 68, 82 and various decimal relocations there of. Don't waste your money on pre-war value parts....Get the closest post war capacitance value and you'll be fine (especially on lytics where the original tolerance was shockingly broad). On multi-section electrolytic caps use several single section caps to replace it....There are companies that make replacement multi-section caps but they are generally not worth it unless you are restoring a holy grail model worth 4 figures.
Short leads can make things harder. Just radios and Bob's capacitors both only sell parts with good lead length, but are more expensive and shipping takes a long time. I typically buy from Mouser or digikey. For lytics I favor Panasonic, Nichicon, and Illinois Capacitor, for film caps Panasonic (especially the red ceramic cased film caps), Illinois Capacitor, and WIMA. You have to look at the data sheets and part numbers to make sure you're ordering the long lead film caps.

Don't replace capacitors under 1000pF/uuF which are almost always mica...On the flip side caps 1000pF=.001uF are just about always paper (and should be replaced) even if they're disguised in the same domino cases associated with micas.