Tube ID - Videokarma.org TV - Video

timmy · #1 03-31-2020, 12:02 PM

I have a small tube that goes to a tuner but the number I can't find any info about it, 210302a, the 210 is above the 302a That's the way it's on the tube maybe someone has a book to figure out a real number like all others have. I'm trying to see if this set is worth doing anything with. So far I get a line across the screen looks like no verticle drive at all. Checked all the tubes . Would there be anything simple to check why the verticle is dead. I don't have a schematic yet until I know I will do something with it.

Electronic M · #2 03-31-2020, 01:14 PM

If the set it is in has Sam's coverage between 1950 and 1967 there is a 98% chance the tube chart is sitting 10' behind me and I could post a picture of the tube chart... I could probably post a pic of the vertical section too...you gotta post the make, model/chassis or preferably the Sam's number for me to look it up.

timmy · #3 03-31-2020, 01:18 PM

Well this set is a cbs Columbia and the only schematic is on eBay but until I can get a full screen I don't want to get it yet. ETF don't have the SAMs . The chassis is 22c38

Electronic M · #4 03-31-2020, 01:21 PM

I have almost every Sam's between 101 and 860 and a several drawers worth on either side...I probably could pull the folder from my files and post pictures of needed sections for you here free of charge...

timmy · #5 03-31-2020, 01:26 PM

That would be great, thanks

Electronic M · #6 03-31-2020, 01:40 PM

Quote:

Originally Posted by timmy

That would be great, thanks

It is listed in Sam's 214 and 255 here's the tube chart and vertical stage of both Sam's.

timmy · #7 03-31-2020, 05:30 PM

Is it possible to use a ceramic cap in the verticle to see if the caps in verticle are bad which I'm sure they are since they are 65 years old, I just want to see if I can get a full screen and how bright the crt is, just temporary.

Polaraligned · #8 03-31-2020, 05:58 PM

Seems easy enough to just replace the electrolytics there and then troubleshoot if necessary. Really a basic vertical circuit.

timmy · #9 03-31-2020, 06:11 PM

Quote:

Originally Posted by Polaraligned

Seems easy enough to just replace the electrolytics there and then troubleshoot if necessary. Really a basic vertical circuit.

Electrolytics were changed but not the paper caps. Thinking of trying ceramic caps to see if this is the problem in the verticle only in place of a paper cap. Because if the verticle output trans is bad then I'm done with this set, it would not be worth it.

Electronic M · #10 04-01-2020, 09:57 AM

You could sub in ceramic as a will it sweep test (results may not be as linear or on frequency as desired).
Personally I'd just ohm out the transformers and if it is within tolerance recap the vertical properly.

You could also connect the output grid to the heater line via a cap to force the output to sweep some.

timmy · #11 04-01-2020, 12:33 PM

Well I could check the ohms but I'm really going need the schematic because I can't make out the numbers for the transformers its Alittle fuzzy.

timmy · #12 04-01-2020, 01:16 PM

Well on T4 I get nothing from both primary and secondary which I feel is odd because when a transformer goes usually there is at least one half would have some sort of reading, I get zero on both. So I guess this is the end of the road for this set. Ok, maybe I measured it wrong, the SAMs shows a red but I have no red on T4 I have green and blue on one side and white and yellow on the other side so I checked for ohms on the green and blue and its zero the same for the other 2 but if I cross over from one side to the other I get a reading, the green and the yellow or white its reads but I'm not sure if this is correct like other transformers. Maybe I got ohms crossing over because maybe there is a center tap . I need some light on this one befor I do infact give it up .

timmy · #13 04-01-2020, 01:51 PM

Ok with the colors I have on T4 I measured 1.544k across the white and blue wires and 6.5 ohms across green and yellow. So is this how these transformers are checked using the wires in the corners rather the both wires on one side .

Electronic M · #14 04-01-2020, 03:15 PM

Sam's 255-3 claims vertical output trans has a red & blue primary with 1.6k ohms and a green & yellow secondary with 5.5 ohms that seems to jibe with your measurements/it being a good transformer...colors can fade and a transformer maker can place the lugs or wires anywhere on the transformer they please...you'd have to track down the design engineer that made this and ask them why it is laid out this way.

Theres also a vertical oscillator transformer in this set the grid winding of that is Yel Grn 920 ohms and the plate winding is Red Blue 170 ohms.

timmy · #15 04-01-2020, 03:20 PM

Would that oscillator trans be the small one, T2 if that's the case the one I have here has the colors red and green on one side and the yellow and blue on the other side so this seems like a really odd way to wire a transformer it looks like maybe one wire from one side and one from the other makes up primary and the other 2 make the secondary.