CTC-10 adjustment lug? - Page 2 - Videokarma.org TV - Video

Bill R · #16 09-20-2005, 06:05 PM

Have you checked c718 the coupling cap for the reactance and 3.58 osc. section ? My field service guide showes pin 2 as -5.8 volts. Either Sams or RCA could be wrong, but the RCA guide shows -5.8 ( or thereabouts for all the chassis that use that tube config.

Chad Hauris · #17 09-20-2005, 08:43 PM

Looks to me like howard sams is probably wrong...I seem to remember -5 to -7 volts at that point on a ctc-15 clone and it is the same type of tube.

frenchy · #18 09-21-2005, 01:21 AM

I think I'll just replace all the .01s in that area with 600 volt ones and then retest it and see if anything changes, sounds like a good bet, will report back after I do this. And a .1 that's there too, if that doesn't change anything, it's on to the 2 or 3 misc. caps that are left around that immediate circuit, big deal, will only cost me 10 bucks and give piece of mind anyway, and it's fun replacing caps (I'm sick I think). Thanks for all the input and numbers, fellow color roundie nuts!...Frenchy

frenchy · #19 09-27-2005, 10:04 PM

I've replaced some caps but really don't see any change, color is still kicking in and has good b/w operation but color is just decoding as variations of pink (and green elsewhere if I totally overload the color control), and no tint control effect. Caps replaced were c126, c124, c727, c730, c725, c710, c703, c719, c707. On some channels the tint control DOES have a slight effect but just in the form of turning the color off at mid range and turning it back on at either end - it never changes any colors. So I know the tint control is good (also tested it with ohmmeter). I'm waiting for a 3.58 crystal just in case that ends up being the problem, till I swap that in I am not going to mess with it. And still have a leakage in the tuner tube which I am going to replace too but don't think it's causing this as b/w performance is great.
Should this oscillator be running regardless of anything else, i.e. should it be running all the time even if no color signal is being recieved or no antenna is attached? It should just be running if the set is powered up, period? Could something elsewhere in the color circuit be 'killing' the oscillator?
Good news - bypassing the thermistor in the power supply (which was further popping and crumbling away) really improved the set and the way it looks right now I dont' see why the set needs the pic tube booster on it. Was probably just a cheap fix for other problems (like this thermistor) with the set that the owner didn't want to pay for on an old set like this. This is what I suspected when the tube tested great on my tester too.

Chad Hauris · #20 09-27-2005, 10:57 PM

Check the color killer control, try adjusting it all the way to one side or the other...the color killer circuit may be disabling the oscillator.

frenchy · #21 09-28-2005, 01:42 AM

Yo Chad, I think that did it, thanks! I clipped in my known good tube crystal again (one leg of existing crystal snipped open) and then turned the killer down and bingo now I have normal color operation! Killer control didn't help anything before the recap but where I had left it then was way too far on 'kill'. So it looks like it had been one of those caps I replaced but my lame killer setting was keeping me from finding out it fixed it. Guess now I can reconnect the original crystal just to actually find out if it is good or not to begin with too. Now on to the hard part - the remote control mechanism. Thanks! ...Frenchy

frenchy · #22 09-29-2005, 12:36 AM

Anybody have any suggestions on the remote control chassis and hand unit? I put power to the clicker with a wall adapter and the button switches slightly spark so I know it's got juice but the relays on the remote chassis don't activate on any of the buttons. Tubes on remote chassis tested good, checked a few voltages and seem pretty good. Guess I don't know how to figure this out when I don't know if it's the chassis or the clicker that is not functioning, since I need both to be able to test either. Unless there is some other testing I can do on either alone that will tell me something. The one capacitor can on the chassis is cool and don't really see any paper type caps in there to replace. I assumed both were working at the time the remote control was disconnected by some repairman when a gear broke and made the remote unuseable for changing channels (it would have just spun the motor forever so he pulled some tubes out of it). Hmmm maybe I need to hook the remote to batteries instead in case there isn't enough amps in the adapter? I dunno...Frenchy

old_tv_nut · #23 09-29-2005, 03:16 PM

Try measuring the voltage from the wall adapter while no buttons pushed and then with a button pushed - this will tell you if you are drawing too much.

frenchy · #24 09-29-2005, 10:39 PM

Adapter is 5.1 volts, none of the buttons make the voltage drop to less than 4.9 volts.

old_tv_nut · #25 09-30-2005, 08:30 AM

Quote:

Originally Posted by frenchy

Adapter is 5.1 volts, none of the buttons make the voltage drop to less than 4.9 volts.

Doesn't sound like a problem with current draw. Do you have some info that 5 volts is the correct value? What batteries is it supposed to take?

Chad Hauris · #26 09-30-2005, 09:13 AM

I think many of these old remote transmitters used a mercury battery that was 4.5 volts. Usually there is a label in the battery compartment telling what type to use so you may try to verify what voltage was needed based on battery type. Also, double check the polarity you have hooked up from the wall adapter. As I remember, the mercury battery had the negative terminal at the small tip so it went in backwards from a regular alkaline or carbon zinc cell.

Try holding the remote transmitter right up to the microphone on the set and see if you get some action. Make sure the condensor microphone "phantom power" (270 volts I believe) is present at the mic. Check all of the DC voltages through the signal path beginning at the microphone.

frenchy · #27 09-30-2005, 05:27 PM

It is supposed to take a 4.2V battery, this adapter is set to 4.5 volts, is actually putting out 5 volts. Another adapter I have says 4.5 volts but is putting out SIX volts so am not using it. I figured 5 volts would be no big deal instead of 4.2, no (?) I was going to worry about rigging up or finding a battery that would fit after I make sure it's working in the first place.
I'm going to go thru the chassis fully now and measure every voltage that is on the schematics, and will buy a scanner this weekend so I can post the schems here and maybe somebody can point me to potential bad caps to change. At the phono plug where the mic plugs into the chassis, the schems say should be 165 volts so I'll start there...Frenchy

frenchy · #28 09-30-2005, 10:57 PM

I know I'm using the correct + and - connections on the adapter, and it is DC... attached is a scan of the schmatics for the remote chassis and the clicker...also here's a pic of the gear in the remote control mech I fixed. Glued the halves together with thin film of superglue, and now it should last forever with JBWeld and two washers to make it solid and take the place of the stress ring that normally goes on the stem. I might put little bead of JB along the other side's rim but can't put in in center as that's where the lock ring goes. I need this gear in there just to be able to change the channels since this set even changes the channel electrically from the console via a bar, not a channel knob.

frenchy · #29 10-01-2005, 04:22 PM

One problem turned out to be a missing shield on the first 12ax7 tube, it's only one there that has a ground spring. At least I think it's missing. If I put a shield on it, the 'color up' control stops locking up. Might still be another problem and the shield is just masking it.
Two junky caps in the remote need to be changed too, that's next. The remote now works in spurts on three of the up functions, length changes if you slowly close the button switches so I betcha those caps have something to do with that (and the down buttons and channel button not doing anything.)

frenchy · #30 10-01-2005, 10:45 PM

I'll take pics of it when I have it back together, it's very big with large speaker panel to the right, and great big 2-piece folding doors on each side that cover the whole front. Wider than a ctc-16 that I have that has speakers on both sides. Very deep too. This is one big darn set for not even being a combo.
Not sure they ever actually made that 14-button remote or if was just made for these publicity shots.
With pic tubes back then I can imagine film lights easily washing out most any color picture back then, let alone the glare off the curved screen and safety glass. Plus the problem of syncing the video with the film camera. Even if they just ripped the guts out and stuck a nice bright rear projection unit in the set it and no sync problems, it would probably still get washed out.