Colortrak CTC120

[Kamakiri]

Recently I've had a desire for a really nice solid state console color set, so I put an ad up on CL. Ended up coming home with this very nice '83 RCA GJR698P, CTC120 chassis set. Very nice neighborhood, the people had two brand new Lexus' in the driveway.

They bought it new, and was in perfect working condition when moved to their garage early last year. So, as it is, it's an unknown with some hope for life

Now since it was stored in a garage for almost a year, should I variac this set up, or just plug it in? I have never used a variac on a SS set yet, but now I'm wondering if that might not be a bad idea. I remember reading here NOT to variac a SS set, but I can't remember for the life of me if that's good, bad, or what....

[Kamakiri]

Eh, I powered it up anyway. Absolutely beautiful warm color, just the way I remember the Colortrak consoles

Only thing is that the volume is really low on channel, but fine on snow. Might be the way the TV is reacting to the agile modulator. Are there fine tune buttons I'm missing?

[Kamakiri]

No, definitely something up with the audio. On channel, the audio is low and somewhat buzzy. Almost as if the audio frequency is off. Thoughts?

[radiotvnut]

I don't remember which coil; but, there is a coil in the audio circuit that needs adjusting. If adjusting the coil does not work, you'll have to replace the coil. A schematic will reveal which coil to adjust in the audio circuit.

[zeno]

Quad ( detector) coils used to go on earlier RCA sets & sometimes the IC.
or cap across it.
Uses a square slug, make one out of wood if you dont have one. If it takes more than a small turn it is broke. That should have a good
layout sheet. If not let me know & I will look it up.

73 Zeno

[Jon A.]

It's probably not necessary to use a variac to power up most SS sets because they're not all that old. I would be inclined to do so anyway with very early SS sets or any that have been exposed to dampness and/or temperature extremes over a long time.

[Electronic M]

IIRC there are risks to variacing SS sets such as missing drive signals allowing transistors to conduct full current and damaging themselves.

[Jon A.]

Hit or miss I guess. I've only heard of one set that can't be powered up on a variac but I forget what it is.

[zeno]

Originally Posted by Electronic M

IIRC there are risks to variacing SS sets such as missing drive signals allowing transistors to conduct full current and damaging themselves.

I never blew a SS set running on a variac. I would NEVER do it
to a Sony SG613 set though !
If its a simple supply all you may want to do is jump the on/off
relay & always unplug the DGS coil so the heavy current dont
throw you off.
Switching supplys are tricky cause they go from dead to full
B+ instantly. Kick start sets also a problem to get to start.
Your CTC120 is a kick starter IIRC. Things really get interesting
with newer stuff. All in all every chassis has to be handled differently
on a variac. Rubber fuses ( light bulbs) are often your friend in
troubleshooting
BTW starting a SS set at say 75V the set will draw to much current,
maybe 1.5 A. As you turn it up it drops. At full line a normal set
will draw + or - .75A, maybe pushing 1A on a 36" running
balls out.

73 Zeno

[zeno]

Originally Posted by Jon A.

It's probably not necessary to use a variac to power up most SS sets because they're not all that old. I would be inclined to do so anyway with very early SS sets or any that have been exposed to dampness and/or temperature extremes over a long time.

A very good point from Jon on this. These sets are not the time bombs
that older ones are. They got put away either working or not & for
many years they will stay that way. Using a variac can be complicated,
useless or harmful. Remember SS sets are regulated and will
run normal at as low as 85V maybe less for some.

73 Zeno

[Kamakiri]

Originally Posted by zeno

Quad ( detector) coils used to go on earlier RCA sets & sometimes the IC.
or cap across it.
Uses a square slug, make one out of wood if you dont have one. If it takes more than a small turn it is broke. That should have a good
layout sheet. If not let me know & I will look it up.

73 Zeno

Here's what I've got. It's also got just a little bit of pincushioning on the sides. Didn't see a pincushion control on the set...if there is one.

[zeno]

L201 is the coil.
IIRC these didnt have pin.
The main filter cans used to go, maybe its just starting.

73 Zeno

[Kamakiri]

I got the coil to turn, but barely. That slug's pretty much frozen in place, and I'm afraid of breaking it. It's a very small screwdriver slot. With the end of a metal tipped screwdriver in place, the sound is actually comfortably listenable if you turn up the volume all the way. Remove the screwdriver, and the sound goes really low.

I'll definitely do the filter can after I get this sorted out. There's only one, and it's spring clipped to the chassis, easy job.

[Jon A.]

By the way, I briefly had an XL-100 with the same control panel. The cabinet was a lot plainer and it was obvious that it had been ran into the ground. That was back when I didn't have any good sets.

[davet753]

PM me if you need the coil, I think I have one in my tube caddy. They were a cheap, commonly used part back in the day.