Help Please! with an RCA CTC-9A

[jhalphen]

Good day to All,

I am seeking help for my French friend Wilfrid who is trying to restore an RCA CTC-9A color TV to working order. I will translate & pass on to him the infos.

The TV is complete, not recapped. Caps were sample tested with an ESR meter and appear to be in quite good condition. The set was brought up on a variac and produces a raster and some sort of video. We have the complete SAMS manual and a full set of spare tubes. H out 6DQ5 was replaced as the original tube was severely gassy.

In the 2 pictures shown here, the RCA is fed from the Aurora converter outputting monochrome 525/30 via a Steren 203-103 NTSC VHF Modulator.

My first question is: Could it be that the RCA is unhappy receiving a signal with no color burst ? i've asked Wilfrid to play a DVD in 525/30/3.58 MHz through the modulator to see if we get color. Will post results.

In the meantime, Thanks! in advance for any help/suggestions.

Best Regards

jhalphen

[Don Lindsly]

That TV will play fine on a black and white NTSC signal. From your picture I suggest setting up the color bias controls for grey scale and trying the AGC to increase contrast. If that does not make a significant improvement, then some troubleshooting is in order. Check chroma driver tubes as well.

[andy]

Be sure to replace any paper caps in the set, including the ones in black plastic. It looks like there's a vertical linearity problem (probably bad caps, or resistors).

The snowy low contrast picture could be caused by an open coil at the antenna input to the tuner. TVs from this era usually have two long thin plastic coils in the tuner which are there to match the 300 ohm balanced antenna input to the tuner's 75 ohm unbalanced input. They often go open when lightning hits the antenna. I've seen 2 or 3 sets with this problem. They aren't too hard to rewind if you have to.

Finally, as soneone else said, try going through the gray scale adjustment. Even with no signal, you can adjust that properly.

[oldtvman]

Before assuming any type of color problem always make sure the purity and gran scale are correct. Turn down both blue and green screens and background controls and them set the purity to a pure red screen. Then bring the other color up to achieve gray scale. The other problem with those sets are burnt resistors in the screen circuits and leaky caps. Then can mask the problem and have you chasing your tail. After setting the bascis, check all screen voltages on the crt and make sure they are correct. If the crt is good the problems should be resolved

[oldtvman]

The picture on my avatar is on a ctc 9