My first Silvertone - Page 4 - Videokarma.org TV - Video

jeyurkon · #46 03-18-2012, 12:23 PM

I count three paper caps. Are you counting the electrolytic as a paper cap? While it needs to be replaced it's not classified as a paper capacitor.

The dark brown could be either a mica or paper. You need to look at the color code to determine that, or figure it out from the schematic and parts list. If the brand is Micamold you'll probably need to replace it even if it is mica. I'd leave it alone until you're sure.

The other things that look like coils on resistors are probably chokes.

Quote:

Originally Posted by charokeeroad

In this photo, just north of the first photo, I can Identify four paper caps that should be replaced, right? The Pyramid being a lytic. What about the dark brown rectangular one in the upper right corner? Is that a plastic covered paper cap or a Mica?

Phil Nelson · #47 03-18-2012, 12:40 PM

Quote:

Originally Posted by charokeeroad

Should I just look for the caps that I know need to be replaced as described in the antiqueradio website?

Yes. Replace the obvious stuff first.

As John (and the article) noted, you can also use the value as a clue whether to replace. For instance, in your second photo, the whitish cap in the middle is marked .02, too big for a mica and too small for an electrolytic -- just right for a paper cap, so get it out of there.

I don't see anything to replace in the second photo. You're doing OK so far. Don't worry about the other components for the time being. The doughnut-ty shaped things may be peaking coils, and so on. You will have time to learn more about other components while waiting for your capacitor order to arrive.

Phil Nelson

ChrisW6ATV · #48 03-18-2012, 03:31 PM

Quote:

Originally Posted by charokeeroad

In this photo, just north of the first photo, I can Identify four paper caps that should be replaced, right? The Pyramid being a lytic. What about the dark brown rectangular one in the upper right corner? Is that a plastic covered paper cap or a Mica?

As Phil and jeyurkon said, I think you are doing well with your progress. Three wax caps and a paper-covered electrolytic that should be replaced. The brown "domino" or "traffic light"-type one can probably be verified with a mixture of looking at its colored dots to see whether it is paper or mica, trying to find it in the Photofact picture, and tracing its ends to easily-identifiable parts nearby (does one end go to pin 6 of the tube socket in the upper-right corner? Check the schematic to see what cap is connected to that tube pin, etc.).

charokeeroad · #49 03-18-2012, 06:41 PM

Thanks for all the feedback. I took another picture of the brown cap and matched it to the schematic. It's attached on one end to chassis ground and the other end to pin 8 of the Vertical output tube, 12BH7. By looking at this cap I wouldn't have thought it was a lytic but the schematic says it is.

jeyurkon · #50 03-18-2012, 06:58 PM

It's definitely not an electrolytic. I think you might have identified the wrong tube.

Quote:

Originally Posted by charokeeroad

Thanks for all the feedback. I took another picture of the brown cap and matched it to the schematic. It's attached on one end to chassis ground and the other end to pin 8 of the Vertical output tube, 12BH7. By looking at this cap I wouldn't have thought it was a lytic but the schematic says it is.

Phil Nelson · #51 03-18-2012, 07:09 PM

Perhaps you counted the pins wrong or you're looking at the wrong tube. When looking from underneath, pins are numbered clockwise starting at the key, or gap between the highest numbered pin and number 1.

That electrolytic is C5, a 100-mfd cap. Anything that size will be bigger than a paper cap. Look at page 9 in the Sams manual and find the circle with C5 inside. The arrow points to its location.

I seriously doubt that little square flat cap is anything other than a mica. All of the flat, plastic-coated paper caps that I've seen were rectangular rather than square.

Phil Nelson

jr_tech · #52 03-18-2012, 07:11 PM

Or perhaps counted the pins wrong, confusing Pins 7 & 2 with 8 & 3.

jr

Add: Phil beat me, so there are 2 votes for improper pin count.

wkand · #53 03-18-2012, 07:36 PM

HI:

If you need a brightener, and think it would help, I have several for series and parallel heater strings. I am assuming yours is a parallel heater set since the set has a big honkin' power transformer.

charokeeroad · #54 03-18-2012, 08:15 PM

I had the wrong tube, It's attached at one end to ground and the other end to pin 7 of the 6AV6, it's C66, 1500MMf. Should I replace it?

charokeeroad · #55 03-18-2012, 08:16 PM

Quote:

Originally Posted by wkand

HI:

If you need a brightener, and think it would help, I have several for series and parallel heater strings. I am assuming yours is a parallel heater set since the set has a big honkin' power transformer.

Thanks for the offer but I just got a NOS CRT a couple weeks ago.

old_coot88 · #56 03-18-2012, 08:41 PM

If you haven't already done so, be sure and check that 270K resistor going to the wiper of the height control. It's the plate load resistor of the V.osc. It tends to go 'waay high in value because of being constantly hammered by a high level pulse during operation. It's a very common failure across all brands and vintages of sets. Well worth bookmarking.

jeyurkon · #57 03-18-2012, 08:55 PM

Quote:

Originally Posted by charokeeroad

I had the wrong tube, It's attached at one end to ground and the other end to pin 7 of the 6AV6, it's C66, 1500MMf. Should I replace it?

I'd leave it alone for now.

John

charokeeroad · #58 03-18-2012, 09:03 PM

Quote:

Originally Posted by old_coot88

If you haven't already done so, be sure and check that 270K resistor going to the wiper of the height control. It's the plate load resistor of the V.osc. It tends to go 'waay high in value because of being constantly hammered by a high level pulse during operation. It's a very common failure across all brands and vintages of sets. Well worth bookmarking.

It looks like R65 on my schematic. ,red,violet,yellow. It tested 320-330k, +/- 10% at max should be 297K. I'll replace it. Thanks.

ChrisW6ATV · #59 03-19-2012, 12:23 AM

Quote:

Originally Posted by charokeeroad

It's attached on one end to chassis ground and the other end to pin 8 of the Vertical output tube, 12BH7.

Quote:

Originally Posted by charokeeroad

I had the wrong tube, It's attached at one end to ground and the other end to pin 7 of the 6AV6, it's C66, 1500MMf. Should I replace it?

This happens to all of us, and double-checking things is how we figure out the right answers and get better at it as we go along. Now that you know for sure what part it is, here is another tip: Look at its color markings, and see how the colors you find match up with its value (1500uuF, or 1500pF, or .0015uF) as listed in the manual, and compare them to the color codes for this type of capacitor. Do they match? If it appears to not match, try to figure out what is wrong. One or more colors may have faded, or maybe the markings are not as obvious as they could be. Comparing things like this can help later when you find items that really are hard to identify.

charokeeroad · #60 03-19-2012, 10:12 AM

Thanks Chris. I'd like to take one more shot at identifying this cap. It doesn't have any color dots on it that I can make out. It's Solar and from what I've read on Phil's website it should come out right? Is it a paper cap wraped in plastic? I can't repost the picture but it's the same one as shown in entry #49.