Director 21 resto begins....

[old_tv_nut]

Originally Posted by miniman82

No, it has a band with round magnets on it. I need to do the same thing you did on your 5, but I don't have a spare set of hardware to modify. My main issue is what to do with the yoke; it doesn't mount to the CRT neck, it's held by the large metal piece which also supports the CRT. Perhaps there's a way to use a later yoke with the pull up ring?

Looks like you have the edge magnets screwed out towards minimum strength - I'd guess that's the best position. If the ones on the bottom aren't screwed out all the way, you might try that. Also, if you have a small refrigerator magnet, you could try moving it around the bell about halfway back to see what effect you get.

I'd try getting the purity with added magnets before changing the hardware. I had no choice on the -5 when I went to the glass tube.

[miniman82]

Yes, most of them are at min strength. The only ones I had to actually use were the ones at the bottom left side of the tube, and you're right, thye are a strong effect at first but it quickly diminishes at the center. I'll try an additional magnet farther back, sounds like a good idea.

[miniman82]

I noticed that the crosshatch pattern looks funky, anyone ever see something like this? It looks mostly fine, until the solid horizontal line passes through the vertical one right in the center. It's like the horizontal line causes some ringing in the video amp or something, see the squiggly vertical line? It also looks funny on the left side, something that was pointed out by a member on ARF. At first I didn't think anything of it, but there's clearly an issue there. See how the horizontal lines continue off screen, while the vertical line of brightness that stops near the edge?

I checked my other sets, and they don't do this. Think maybe it's because of all the inductors in this chassis? It does have 10 times the number of peaking coils than any other chassis I've worked on, but I'm inclined to believe it should still be able to display a simple cross without an issue. Thoughts?

Second shot is just more brightness than the first.

[old_tv_nut]

looks like sync separator problem - white video causing the sync to be clipped at a different level. I also notice it occurs at the top, where the horizontal sync has been disturbed by vertical sync Do you have a multi-square crosshatch? Does the wiggle follow every horizontal white line?

[old_tv_nut]

Also might try turning the noise threshold control to see if it affects this.

[miniman82]

I was thinking sync as well, but it's so darn stable! I can twist the horizontal control multiple times, and it stays locked. Vertical is pretty solid too, is it possible to have stable sync while still having an issue? Yes, it happens with the multiple chrosshatch too- at the intersection of every horizontal line, the vertical gets a little squiggle to it. Noise inverter and AGC have no effect on it.

[old_tv_nut]

Well, now I'm just fishing, but have you checked component values in the horizontal oscillator/control section? Even if it's getting an input jolt it shouldn't get, I think it maybe should respond with a more damped response instead of a decaying oscillation.
The following three components are the main control loop filter:
C160 .01
R165 3900
C159 0.47

+ other R's and C's in the vicinity

[miniman82]

All the caps and resistors in the horizontal section are either new or within tolerence. I thought I was having a problem with the originals before, but it ended up being a power supply wiring glitch that was my fault. The power supply is fine now, and I strongly doubt issues with the oscilator.

[miniman82]

Thanks, Wayne!


In the end, you were right. When I initially set this thing up, it still had a miswired power supply with 60hz noise. That means I tuned the horizontal sine coil with that same noise in it, but I failed to recheck it after I corrected the problem. Looked at it with the scope the other day, and sure enough the first hump of the waveform was was lower than the second one! I watched the screen as I tweaked for equal humps, and sure enough that coil being detuned will cause the ringing I was seeing. Now I have nice straight lines on the screen, just like I should.

[old_tv_nut]

I wasn't thinking of the sine coil, but it makes sense because it could affect the pulse shape going to the phase detector. Glad you found it!

[miniman82]

No matter, you got me looking into the horizontal section and that's what sparked my pot-frazzled memory.


OK, so at this point I did a very rough setup with the bar gen and reconnected the tuner. Still have some issues with a dirty AGC and color killer pot, those will be next on the clean/deoxit schedule. Here's the result, as seen via the Crapcast DVR!

Getting very close to a good picture now, all I have to do is another round of purity/convergece,
and nail the color alignment. What was that about keeping me off the streets for a while?

[miniman82]

Did work on red purity, and was able to just about cure that patch on the bottom of the screen and left hand side. Looks pretty good now, aside from a few little issues with red convergence in the bottom right corner. Can't really see it from normal viewing distance. I think I'm gonna call this a winnah for now, I'd like to enjoy it for a while before I send it off for refinishing. that will be the next problem, since all the people who work on wood around here are booked till the return of Christ. Any leads on someone who's free to do that kind of work?

[Phil Nelson]

I know a great refinisher here, but you probably don't want to ship the cabinet to Seattle.

Looks like you're making real progress. I'm glad you mentioned the horizontal squiggle. I have seen that before (don't recall exactly when). If I see it another time, I'll know what to look for.

Phil Nelson

[miniman82]

No, I'm definitely not up for shipping it across the country. I'll just have to keep bothering the refinishers around here till they help me I guess, I just can't believe more people aren't getting into woodworking. With the economy in the tank, you would think people would flock to a trade that's always telling me they have no spare time to help...

Maybe they just want nothing to do with an old TV cabinet.

[miniman82]

Thanks for the nice Sams CTC-4 Photofacts, Brian! Now I can align the matrix correctly.