No color on an RCA CTC-16

[old_tv_nut]

Are you sure the chroma bandpass amp plate is the same voltage as the screen grid (148 v)? That's not right, for starters.

[Jon F]

Originally Posted by old_tv_nut

Are you sure the chroma bandpass amp plate is the same voltage as the screen grid (148 v)? That's not right, for starters.

I copy-pasted the 148V from pin 3, pin 6 should have read 268V. I updated the image below.

Originally Posted by oldtvman

At some point an oscilloscope is the best and easiest way to pin down problems like this.

I have a scope, but do not use it much so my skills in diagnosing a TV with it are limited. Any tips on waveforms I should check?

[Yamamaya42]

Then at this point, as oldtvman said, you won't get far w/o an ntsc color bar generator & an o-scope, cause if what you show is true, V17a is in a normal state, so the input needs to be checked, but w/o a color bar input ( to look for the bottom waveform shown with the circle) it will be very hard to progress without it using just standard video input.

[oldtvman]

Originally Posted by Jon F

I copy-pasted the 148V from pin 3, pin 6 should have read 268V. I updated the image below.


I have a scope, but do not use it much so my skills in diagnosing a TV with it are limited. Any tips on waveforms I should check?

If you have the schematic and it appears you do, it should show waveforms for different points of the set. I know Sams has waveform pictures based on using a color bar generator.

[Electronic M]

Originally Posted by oldtvman

If you have the schematic and it appears you do, it should show waveforms for different points of the set. I know Sams has waveform pictures based on using a color bar generator.

Even if he doesn't the ETF has the CTC-16 sam's in free PDFs on it's site.
http://www.earlytelevision.org/tv_sc...ams_color.html