Rca ctc-5

[Penthode]

Originally Posted by DaveWM

i check those two resistors in the plate circuit R603 and R604.

R603 is coded as an 82k which was on on the CTC-5 but shown as a 100k on the N chassis. I checked it out of the circuit and it had drifted up to about 94k so I left it alone.

the R604 which is coded as a 39k tested at 60k. Its 10% banded so I went ahead and replaced it with a 39k (tested at 41k) from my stash of old carbon comp resistors.

With R604 now in tolerance, you should see more drive and the bias on the horizontal output higher. Please let us know the result.

[DaveWM]

will do.

I noticed in the RCA service manuals the CTC-5N had the 100k listed with 120k and 150k alternates. My plan is to try it as is (with the new 39k) and then try a 120k for the R603 (vs the 94k reading 82k resistor that is in there now.

all this time I have been saying I have the N chassis, I just double checked, its a AA chassis.

[Penthode]

Originally Posted by DaveWM

will do.

I noticed in the RCA service manuals the CTC-5N had the 100k listed with 120k and 150k alternates. My plan is to try it as is (with the new 39k) and then try a 120k for the R603 (vs the 94k reading 82k resistor that is in there now.

all this time I have been saying I have the N chassis, I just double checked, its a AA chassis.

I did find raising the resistance slightly improved the HV supply slightly. But the increased drive may have slightly stretched the left side of the raster.

I think the problem is the back flyback HV supply design with limited beam current in this set. It would be nice to be told whether or not the CTC5 picture is as dim as other color sets of the same vintage.