Another newbie question (choosing capacitors)
 

I am getting ready to attempt to do something many of you can probably do blindfolded by now. First I need to buy what I need.

Can someone please tell me how I interpret this chart from my schematics when I go online to buy new capacitors? Maybe can you choose a line and show me how I should make sense of it and then what to look for online? I guess actually it's just the rating column that's hard because the new capacitors I see for sale don't match what is there.

I would appreciate it.

Actually we can only guess blindfolded, or with the data supplied.

The small numbered ones with things like N75 are
ceramic caps and almost surely good. Numbers 1000 or less
are probably in pF ... but we need to know if they re
ceramic, mica, or (unlikely) paper.

Numbers with a decimal point between .001 and .68
are probably paper but might, for some values, by mica or ceramic.

We would need to look at the schematic or a good photo of the
set to tell.
Experience tells one what kind from a schematic.

Is there a special list for electrolytic caps?

What is the set?

Thanks for your help. Much appreciated. All of the pics of my set are in this thread.

http://videokarma.org/showthread.php?t=266883

I would like to learn how to replace the capacitors as it is such a common and necessary job. I do have the link to antique radios with the instructions. I went out and bought the tools yesterday. Just need the capacitors.

I have some books from the 60s but they dont talk much about this I guess they wouldnt have gone bad yet back then.

We need to see the schematic.

It may well be that a set that new is filled with
still good ceramic caps and needs only the electrolytics replaced.

I'll explain those electrolytics. One is a single, the
others are cans.

First the single. It says 150uF. 200v. Let go looking. Mouser has an axial direct replacement at over $6.
Justradios.com has no direct replacement; best is a 250volt 220 uFD ... which would work fine
since its surely a filter cap, at $3 or so. That's still expensive! What I do next is look for radials at Mouser (or Digikey).
I go to electrolytic caps, leaded, radial, stocked.
I usually also select bigger uF value Nichicon and Panasonic, but United Chemi-Con sometines has ones they don't.
I selected 150 uF and 180 uF, and 250 volts ( its better to go to the next common voltage, though in this case 200 is fairly common
) and for filter caps, the specified value and the next up in the usual series
(10, 12, 15, 18, 22, 27, 33, 39, 47, 68, 82) , That gave 12 items, which means you will be OK.
The cheapest 150 uF cap is rated at 105 degrees C and over 3000 hours lifetime, so its a
quality product, so I'd buy that.

Presumably you are going to restuff the two cans. If not, and just clipping them out of the
circuit, and mounting the new ones under the chassis, you use the same procedure. For the >250 volt
caps, just use 450 volts and use the next value up in the
standard series. I.e. for 20 uF I'd use 22 uF, and for 4 uF I'd use 4.7. For 25 one
uses 27, and for a specified 50 you
can use 47, or more usually 68. If its the second capacitor in the line
of the main power supply, I'd go up to twice what is speced. For the first cap
in the line of the main power supply, us the next value up ... not lots higher.

For the 25 volt ones, you CAN use 25 volts, but I usually use 35 or even 50.

There are no caps in this set where one needs to look beyond the "usual suspect"
Panaconics and Nichicons, that is, 105C and >= 3000 hours spec. Just get the cheapest
that fits that. In a tube TV set there is no need to look at the ESR or"AC Amps" columns.

Now if you want to restuff the cans, there is an additional nightmare. WILL THEY ALL FIT?
New caps are much lower volume ... but the shape may be wrong to get them all to fit. There
are instructions here and at antiqueradios.com on how to do the restuffing. If you want to be sure they fit, you have to
carefully look at the sizes and imagine how you are going to arrange them inside the old can.
Sometimes its impossible, even if you don't try to use higher than the specced voltage.

If you really need caps rated greater than 450 volts, go to justradios.com,
or stack two 350 volt ones of twice the value and just don't worry; just be sure they are from the same batch!

Thank you for that valuable information. I will have to study on that a bit. Actually a lot. The article on antiqueradios does make it seem 'doable' for a novice but now I am not so sure. Looking at my chassis it seems to me I can see where I am going to cut and solder. I can see the large, wax paper capacitors that need to be replaced. I know most of them are the type that never get replaced. I was just going to go down the list of capacitors on the image I posted and buy all the type that are paper and then put them in according to the schematic. Wrong idea? I think I should check youtube too, hopefully someone filmed this procedure. How in the world did most of you get your start? I feel like I am not smart enough to be in this hobby but for the love of my sets and all things '60's' I am going to try like hell.

If they look like paper, just buy film (radial) Panasonics in the correct values from
Mouser or Digikey. Its traditional to use 630 volt ones unless a much lower
voltage (like 50, 100, or 200) is specified and the 630 volt one is just too large.

example:

http://www.mouser.com/search/Product...eyECQ-E6223KFW

At that age set, you are unlikely to need a cap that is like 0.05 uF. If you do,
replace with the nearest standard value. Get 10% tolerance caps unless a
5% tolerance of better is specified.

If a higher voltage is specified, get that.

The only exception is if it is connected to the power line. Then you need special "safety caps", look that up here at videokarma.

Paper caps are easy! Just do it.

As to how I learned ... I did it at age 11 by building Heathkits and reading. Read
things like 1955 vintage books. Also the repair columns in that vintage trade
magazines: e.g.

http://www.americanradiohistory.com/...aster_Page.htm

I was a radio collector/restorer before I got into TVs. Get an AA5 tube radio and recap that first for practice. There will be only 2-4 lytic sections and ~1-8 paper caps. The wiring is usually simple and not dense, so it is easier to find your own mistakes.

If you want to ease into TV recapping do an AA5 then a 7-12 tube console chassis. You will get good practice on an easier circuit and layout.

This is very good advice. I think you just made my plan.

Thank you again for taking your time to educate me and provide me with all the information you did! Very much appreciated. Great links and suggestions, I am sure this will help me tremendously.