Need yoke part numbers - Videokarma.org TV - Video

miniman82 · #1 12-03-2011, 02:09 PM

The 9-T-79 I'm working on has insufficient width, and some bad ringing in the horizontal waveform. The yoke was replaced at some point, so I'm thinking it was replaced with the wrong one. It looks identical to the one that was on the TC168, which had a 16" CRT. If you guys could provide some numbers for Merit/Thordarson/Stancor/Chicago/ect, I might be able to confirm it's the wrong one. RCA number from Sams is 74952, only marking on the one in the set is 970669-1.

miniman82 · #2 12-03-2011, 02:41 PM

Just got off the phone with Chesters in Kenosha, they say Thordarson Y-17 is a sub and if they had one it would be $10. Anyone got a spare they don't need?

I read out the resistance on the windings:

Sams calls for 43 ohms on the vertical, I get exactly that.
Sams says 13.5 ohms for horizontal, I get only 3.

Additionally the schematic shows a 56pf cap across the top vertical coil (connected to pin 4) which this yoke has, but it also shows a 270pf from the center of the horizontal coils to pin 8 of the bottom vertical coil which it does not have. The installed yoke also has a 5.6k resistor from pin 1 (horizontal) to another part of the same coil. I assume it's across one of the horizontal coils.

I'm convinced this is wrong for this set.

Kevin Kuehn · #3 12-04-2011, 04:03 AM

I have one NIB, but heck, I'd take Chesters up on that one for $10.

miniman82 · #4 12-04-2011, 02:57 PM

Quote:

Originally Posted by Kevin Kuehn

I have one NIB, but heck, I'd take Chesters up on that one for $10.

Quote:

Originally Posted by miniman82

...if they had one...

I'll take yours, what are you asking for it? Any chance you can pop the cover off the back, so I can see if it's different than the one I have?

Kevin Kuehn · #5 12-04-2011, 08:03 PM

Nick,

Here's a couple pictures. Weird that the internal components do no match what the schematic shows. The 56pf cap is in the right place, but then the other cap is missing, and there's that 560 ohm resistor. I'm pretty sure the plastic cover had never been off, looks all original. The resistance readings check out ok. Maybe your TV schematic can shed some light on it. Anyhow, $15 if you can use it. I also replied to your pm over on ARF.

Kevin

dieseljeep · #6 12-04-2011, 09:34 PM

Quote:

Originally Posted by Kevin Kuehn

I have one NIB, but heck, I'd take Chesters up on that one for $10.

Are you kidding. Chester the molester! If we had it we'd sell it for $10. I needed a 1DB3 HV rect. for a GE porta-color. They wanted to nick me $14 for it. I told them forget it! It's not an audio tube! Probably the last time I'll darken their door.

miniman82 · #7 12-04-2011, 09:38 PM

Quote:

Originally Posted by Kevin Kuehn

Weird that the internal components do no match what the schematic shows. The 56pf cap is in the right place, but then the other cap is missing, and there's that 560 ohm resistor.

Interesting. But you do get a full 13.5 ohms on the horizontal coils, right? Mine only has 3 ohms, so if yours reads out correctly I'd still like to try it.

Edit: your yoke has a 560 ohm resistor, mine has 5600... Wish mine had some good part numbers on it.

miniman82 · #8 12-04-2011, 09:42 PM

Quote:

Originally Posted by dieseljeep

I needed a 1DB3 HV rect for a GE porta-color. They wanted to nick me $14 for it.

That's an uncommon compactron tube, prices for more common ones are pretty reasonable considering it's a store you can walk into and buy tubes.

Kevin Kuehn · #9 12-04-2011, 09:49 PM

The specs with this one say 43 ohms Horz, 3.5 ohms Vert. I'm reading 44 and 3.1 ohm

I double checked with my Thordarson catalog and they give the same resistance values.

miniman82 · #10 12-04-2011, 09:56 PM

Something's fishy...

The Sams for this set says 43 ohms vertical, 13.5 horizontal. Here's a snapshot of the schematic.

Kevin Kuehn · #11 12-04-2011, 10:27 PM

Quote:

Originally Posted by miniman82

Something's fishy...

I agree. I don't know what to make of it. Possible SAMS is messed up as well. I guess at this point you need one or more other manufacture cross-references with specs, at least to come to some consistent conclusion.

Below is the complete spec sheet that was in the box.

Kevin Kuehn · #12 12-04-2011, 10:50 PM

Maybe someone can see what yoke specs Riders lists for this TV?

Electronic M · #13 12-04-2011, 11:55 PM

Definitly check riders to confirm. I've had Sam's typeos F^ck me up on part values and locations twice now! When in doubt check other sources.

miniman82 · #14 12-05-2011, 01:03 AM

Quote:

Originally Posted by Electronic M

Definitly check riders to confirm. I've had Sam's typeos F^ck me up on part values and locations twice now! When in doubt check other sources.

Mmm-hmm.

How much you wanna bet those tards at Sams fat fingered a 1 in before 3.5 and ended up printing 13.5 instead? I can almost see it happening, and it makes sense since the one I have here reads the same 3.5 ohms as Kevin's does. Hmm, maybe the yoke isn't to blame for my horizontal troubles after all?

Since we're on the subject, I was trying to get some work done to the 21CT55 the other day, using the assistance of my RCA service guide. It's having issues with noise in the picture, so I was attempting to trace it back to it's source in the schematic. I got to a point where I was searching the 1st video and chroma bandpass amp tube circuits, and realized that the schematic showed the grid of the chroma amp tube going to the contrast control wiper. Mmkay, here's pin 8 on the chassis, follow wire back to.... the color control?!? WTF!!! Scratch head, consult Sams... Sure as sh!t, the RCA book has a damn CT-100 schematic labeled as a CTC-2B!

So it's not just Sams, I guess. I'll have to apply my car salesman mantra of "no trust" to schematics as well, since I have yet to find one that exactly matches ANY chassis I currently own.

Kevin Kuehn · #15 12-05-2011, 10:21 AM

Pretty frustrating. Good thing we're only in it for the hobby.