Tube ID
 

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.

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.

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

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...

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.

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.

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.

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.

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.

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 .

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 .

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.

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.

Yes.

Ok well here's the numbers for the verticle oscillator transformer, your number was 920 and my number was 1014k and the other, yours 170 and mine .184k those numbers seem ok compaired to yours. Back to the drawing board.

Tom is it possible for you to tell me what the brightness pot is listed as ,what ohms because someone had changed the pot and the brightness will not turn the screen down and wilth a bright line across it will burn in if I have it on checking voltages.

Brightness control is 100K. Ends are connected directly to 120V B+ and Ground, wiper connects to cathode via 270K resistor. G1 connects to ground via 1M. G2 connects to boost. Gun voltages should be 45, 0 and 440.

Thanks for this info, it will help.

Well I compaired the voltages, yellow 82 v bright down screen still lit, green 75 v red 472v , orange 285v I assume focus , black and brown heater. No 45v or 0 . The bright pot measures 135k but it's still lit no matter which way it's turned and the 270k resistor is good . I'm wondering if whatever is going on with the brightness has anything to do with verticle. :scratch2: the 120v on the bright pot is there and the other end has a wire from there to the verticle hold pot which is tied to ground.

G1 is supposed to be 0V. It should have a 1M resistor connecting it to ground and it also has a cap connecting it to something. It sounds like G1 has become positive with respect to cathode in your set....that will give you 150% brightness regardless of brightness control setting on cathode.

Check the 1M resistor on CRT grid G1 for open and the cap that goes to G1 should be changed or disconnected.

Well that was a good call I have never came across that in the past I haven't worked on these sets as much as you have. The 1 meg tests at 1.3 meg and I clipped the cap and now the brightness works it has one of those bumblebee caps I don't know the value because it has color bands. So I guess I'm on to hopefully find why this verticle is not oscillating. Is the g1 cap even needed .Thanks tom

Glad to help.
Regarding bumble bee caps. Can you read resistor color code? And are you familiar with modern capacitor rating nomenclature that uses 2 digits and a multiplier to express capacitance in picofarads (is 102 is .001uf(1000pf), 153 is .015uf, 224 is .22uf)?....a bumbel bee is the modern numbering system encoded using resistor color code...the first 3 bands are capacitance there is usually a 4th grouped with the capacitance bands that I believe is tolerance (I typically ignore it) then there's 1-2 more bands that are further away representing the voltage in hundreds. A single red band is 200V a pair brown and blue is 1600V.

Is this bumblebee cap even required at all ?

I'll have to look at the schematic when I go back to the basement later...I didn't check what it went to only that it could cause CRT bias issues that you were experiencing. I think video was cathode driven so the grid cap could be something like a retrace blanking circuit... I'll get back to you.

Ok ,thanks

I'm coming up with 2 different numbers for this cap. .047 and 47.
Yellow
Violet
Orange
Grey And blue by its self.

Yel violet orange is 473 which is .047, and Sam's says it is a .047 600V. It couples the plate of the video output to the CRT grid so completely necessary if you want video on screen.

Last night I had the things backwards going from memory. The CRT gets its video at it's grid and there's a vertical retrace blanking circuit feeding the CRT cathode off the yoke winding of the vertical...here's some pics.

Ok so I don't know if I'm correct in thinking that the verticle circuit starts at the oscillator then to the output then to the yoke. So the tube oscillates the oscillator transformer then that oscillates the output transformer. I'm trying to get a better understanding of how this seemingly simple circuit works. There is supposed to be 90 volts at pin 6 and there is not and -26 at pin 7 and 22v at pin 3 is present. If the verticle is running then the voltages should be there . At R77 there is 300 v from the height pot up should show some voltage but nothing near 90 v. Even the worst caps I figured there would be something even a 1 inch high picture but there is not just a razor lines across. The horizontal I would have thought would have been the headache.

I'd change caps C2 77, 78, and C80. Especially C2. Check R6, 76 and R77 too.
Paper caps short or develop excessive DC leakage current and can absolutely kill vertical oscillation and coupling to the output...you already saw what the CRT grid coupling cap leaking did to mess up brightness bias on the CRT...If the osc or output gets mis biased from cap failure leakage current the osc can stop dead or the output can have it's signal cut off.

Any section that has original caps you should expect to find dead and be surprised if it still works.

Ok I'm going to recap the whole set and hope for the best at this point . there are to many old caps to dance around. I'll post the outcome when it happens. Thanks tom for the tech info.

Does anyone know of another company like moyers that sells capacitors, moyers may not be open this coming week and I need capacitors. Maybe a name and phone number someone good that someone here had used befor. Thanks

Sal's Capacitors. Great to deal with and fast shipping. http://www.tuberadios.com/capacitors/ Contact info at bottom of page.

Does anyone know how to figure out the date code of a ge crt . The sticker shows code 6113 then under 188 is 50 and another number. A 103227

I vote for the 13th week of 1961 188 is the EIA code for GE. I think the A103227 is the serial number.

I've done good with mouser and digikeys websites for caps, resistors, diodes, terminal strips, etc.

Gotta, tick the filter by in stock box, and play with some of the filters to find what you need, but the price is usually better than more specialized vendors.

On a 21fjp22 crt , I'm trying to figure out what year this tube was rebuilt. It shows the word code and under that is the number one next to that is 82 then next to that is 9 . Would that be January 9 1982 ?

Ok so it's all recapped and still no verticle, I checked resistors around the vert oscillator tube and a lot of other places for the verticle and they are within range and also double checked the hold , height, linerety, pots all are good. I find that the vert oscillator tube is not oscillating because when I probe number one of that tube with my meter on ohms the screen wants to open so I'm at a loss as to why I can't get this to oscillate. I don't have a voltage chart for this set to check voltages.

Many years ago I ran into an RCA TV that had a vert osc that wouldn't run. The vert hold control read fine out of circuit, but I missed the part where it had about 100K ohm leakage through the case of the control to ground. When I lifted the vertical hold control off the chassis and let it float in the air, the vertical came back.

Long shot to be sure; in 50 years in consumer electronics I only saw this once.

John