UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - ITT CVC7

Stewart · 31st Oct 2005, 8:53 pm

The video stages are out of circuit with the switch in the centre position - hence they can be taken out of the equation if the picture is still dark.

Of the line output valves I would have thought the PY500A boost diode more likely of the two to cause problems - the A1 volts for the tube come from the boost line. But - as I've said before - voltage checks are the only way to pin this one down in my view. Given you have a second example it wouldn't be too hard to rule out the valves by swapping them over.....but I think it will all come back to making a few key measurements......are you in a position to make them?

31st Oct 2005, 8:53 pm	#14
Stewart Retired Dormant Member Join Date: Jul 2003 Location: N.E. Surrey, UK. Posts: 361	Re: Itt Cvc7 The video stages are out of circuit with the switch in the centre position - hence they can be taken out of the equation if the picture is still dark. Of the line output valves I would have thought the PY500A boost diode more likely of the two to cause problems - the A1 volts for the tube come from the boost line. But - as I've said before - voltage checks are the only way to pin this one down in my view. Given you have a second example it wouldn't be too hard to rule out the valves by swapping them over.....but I think it will all come back to making a few key measurements......are you in a position to make them?