color stripes on screen (slyvania roundy)

[reeferman]

Have you checked for bad solder joints?
Crystals seldom go bad.
Only recap as last resort.
The tool has a 1/16" hexagonal on the end and made of plastic. Commonly referred to as a diddle stick. Should be available at Radio Shack.

Assuming you have a CTC-15 clone the attached drawings should apply. In drawing 1 you are concerned with tube V703 and reactance coil L702 (which has only 1 ferrite core (slug) to adjust. Drawing 2 is the schematic. Short pin 2 of V703 to chassis ground. Don't worry about the "B" in the V703B. Adjust coil L702 for the minimum number of color stripes (bars) and at the same time have the color stripes stop moving (floating). Go ahead and play with it. You'll see that moving the coil one way will increase the number of color stripes on the screen and the other way decrease the number of stripes. Go for the minimum number.

Before starting I recommend setting the color killer control. Go to an unused channel and adjust the control all the way to the end that gives you color snow. That way your set might not try to cut back or even kill the color signal.
After adjusting the reactance coil L702, adjust the color killer control by turning to an unused channel, adjust the control to where you have color snow, then back off until snow disappears. A simple adjustment people overlook.

[technicolor]

Originally Posted by DaveWM

oy vey

tweek the freaking osc coil 1/4 turn tall right next to the 6GH8 go 1/4 one way if more bars go the other way. Don't go crazy if it does not help its prob the crystal.

oh yea and use the correct tool so you don't break the core.

This is what reeferman was telling you a while ago, just without grounding the grid 1st.

and this correct tool is called what?

[technicolor]

Originally Posted by Username1

Color is way off frequency, the more bars you can see the more off frequency it is......

If you don't have a tube chart (layout) look on top, or bottom of chassis for a color crystal, its aluminum, about 3/8 thick, and maybe 1 1/8" long, curved on the sides, about 1" tall, flat on top, and most likely has 3.58mhz or just 3.589 stamped in the top. The set will have only 1. Your color circuit is right near this item. This is your color oscillator crystal.

Your color osc. tube will be near it, the cap former Captain Picard is talking about should be near this item. 6GH8A's have short lives, you should keep a few NOS spares, you can switch out from that set to another to try, or with another in that set if you don't have another, you might see a difference if its weak or bad.

For this problem, look to color oscillator, or color afc, circuit, there is a rectangle 3 wire afc diode in that part of the color circuit. Its usually black plastic - almost same size as the color crystal.

PS both the crystal, and the 3 wire diode often are not the problem.

Actually now that I think about it more.... I think the 3 wire diode is the Horiz afc, and not color afc, so forget I said that... getting old....

Also, those caps with the thousands of volts are high tolerance caps, and high voltage rating because it is a critical value not to drift in value, don't worry there is not that much voltage there, its to keep the value stable.

squirrel boy, u got a web page where i can buy that crystal? Is it model specific, i'm hearing my chassis is a ctc-15 clone

is there one on ebay?

[technicolor]

Originally Posted by reeferman

Sorry, man.
Give me the model number so I can send you a picture of the chassis with the necessary items circled and I'll walk you through the adjustment procedure.

Do you have a color generator? If not I recall that several years ago there was an ad on the ETF site for a DVD that had color bars, cross hatch, etc for about $5. Best investment you can make. But you'll need to run it through the antenna terminals for this adjustment.

If you can't find it I'll loan you mine. Just pay postage both ways.

Let me know.
Phil

PS: When you turn to an unused channel do you have color snow? If so, you need to turn the "color killer" control to the left (or right) to the point where the color snow turns to black and white. If you then go to a color broadcast and have no color until you undo your previous color killer adjustment, you may (may) have additional problem(s). Let me know.

Don't be sorry, I'm just starting out and appreciate all the help i can get.



Right now, I'm going to replace this crystal and recap the set.

in my limited knowledge, 49 yo old caps seem highly suspect. Besides after the debacle with the magnavox, as least i know which end is which on an electrolytic, lol.

[Username1]

Don't replace the crystal......

The tools to adjust coils are made of plastic, you can get them on ebay, you use to be able to get them at radio shack for less than $5.

http://www.ebay.com/itm/GC-Radio-TV-...item19dff14f8f

[old_coot88]

Ooy vey indeed. Assuming the set is a '15 clone, the "color oscillator" or "color lock" adjustment is called the 'reactance' coil. It sits adjacent to the color osc. tube and is not in a shield can. It's tall and narrow, having a single winding and single slug. Can't miss it.

The tool is called an alignment tool or 'diddle stick'. It's non-conductive, made of either nylon or plastic. Radio shack used to sell them. If they don't, somebody here must know a source.

(edit) OOPs. Didn't see the above post. Do try the reactance adjustment before messing with the xtal.

[technicolor]

Originally Posted by Username1

Don't replace the crystal......

The tools to adjust coils are made of plastic, you can get them on ebay, you use to be able to get them at radio shack for less than $5.

http://www.ebay.com/itm/GC-Radio-TV-...item19dff14f8f

so your saying try to adjust this thing, and then if that doesn't work then recap?

[technicolor]

Originally Posted by Username1

Don't replace the crystal......

The tools to adjust coils are made of plastic, you can get them on ebay, you use to be able to get them at radio shack for less than $5.

http://www.ebay.com/itm/GC-Radio-TV-...item19dff14f8f

ok i bought it thanks.

[Username1]

Crystals hold a very fixed, and very steady frequency. If the number of color bars increases or decreases wildly, then it may be the crystal. It may be the crystal if it is very far off frequency and you can't get it back on.... Lets put the crystal aside for now. They are not set specific, so one temporarily swiped from another set will be fine. No polarity either.

While I have not worked on a ctc 15, It sounds like "old coot" has, follow his advice and adjust that coil he identified, if you have the plastic tool. Its plastic so its material does not effect the coil. If it were metal, like the iron core you will be adjusting, the tool itself would change the value of the coil as you put the tool inside the coil. The coil will have a center shape like an allen wrench.

Adjusting that coil will either increase the number of color bars, or decrease the number of bars.... You want to reduce them unitll the color locks, similar to horizontal hold. If you can not achieve a stable lock with adjustment, then you have a bad component, resistor, tube, cap.

One thing you can do is to run the set, and spray a little freeze spray on some components around the crystal, to see if you can find a sensitive part, it may be bad. Long shot, and don't waste the entire can. Just a drop or two on components you know are in the color circuit. Don't spray tubes. Freeze spray is a good tool to have, also called component cooler, also ust to be available at radio shack. Maybe also available on ebay.

Be careful when re-capping in the color area, those caps are tight tolerance. Better to try and find the bad parts.

Also see if you can get a schematic from someone here, or ebay, and begin to learn about these circuits so you have some idea about recognizing the parts, and parts of each circuit that depend on the previous circuit for the set to function properly. Sam's have lots of cool stuff in them, even if they are not perfect.

Have a good night....

[reeferman]

See my revised post #16 with drawings

[technicolor]

Originally Posted by reeferman

See my revised post #16 with drawings

Hey thanks i appreciate it. I just ordered the alignment tools on ebay and the sams. We''' see if an adjustment will fix it.

[Username1]

Thanks to reeferman for posting schematics, I would turn coil 703, which is the 3.58 osc. the other coil looks to be tint, or phase. If the frequency is not right, adjusting the phase will do no good. Think of adjusting the frequency as the course adjustment here, and phase, as a fine tuning to get the color right, once the osc. is locked in....

If you short pin 2 of the osc. tube I would imagine the bars would go away...... is this not true reeferman?? Turning off the color osc?

Well whatever you do, don't turn both coils without returning them to their starting point. If you turn one 2 turns to the right, remember it and return it to its starting point. You don't want to throw the set out of alignment for what may turn out to be a bad cap, or out of range resistor, or open resistor..... Check the voltages that are on the schematic while you are there....... First.

[DaveWM]

L702 is the correct coil to adj. it the one that is a coil ouside the can next to the 6GH8. turn it 1/4 turn one way see if you more or less bars if more go back turn 1/4 the other way. It should not need a lot of adjustment.

[technicolor]

Originally Posted by DaveWM

L702 is the correct coil to adj. it the one that is a coil ouside the can next to the 6GH8. turn it 1/4 turn one way see if you more or less bars if more go back turn 1/4 the other way. It should not need a lot of adjustment.

that reddish thing?

[DaveWM]

yes the reddish coil