Recapping a 1955 RCA KCS92d

[Electronic M]

If you have the schematic check the voltages in the set against the ones on the schematic...
How much of a recap did you do? If you have been powering it up every few caps changed it is possible that your work is okay and one of the old unreplaced caps died.

The HV rectifier heater is powered by a winding on the flyback transformer...If the transformer is not being driven properly by the H output/osc system there will be no heater voltage to the HV rect. Most HV rects are hard to impossible to see any glow from even when working properly...So don't worry if it is dark. If you can get 1/4"+ of arc from the top cap of the HV rect, but no arc from the HV connection to the CRT then the HV rect is suspect. You can look up the data sheet of the tube and check if the heater filament is open with the ohms function of a DMM. Substitution with another tube is also a valid test.

If you don't get an arc from the to cap of the HV rect then make sure you change all caps in the horizontal output and osc sections as well as the B+ Boost rail. then check resistors in those sections and check voltages.

[old_coot88]

QUOTE:

"If you can get 1/4"+ of arc from the top cap of the HV rect,..."

To expound a bit for a newbie, use a metal screwdriver with an insulated handle. The screwdriver is ungrounded. It draws the arc due to its innate capacitance in the air.

[dieseljeep]

Originally Posted by Electronic M

If you have the schematic check the voltages in the set against the ones on the schematic...
How much of a recap did you do? If you have been powering it up every few caps changed it is possible that your work is okay and one of the old unreplaced caps died.

The HV rectifier heater is powered by a winding on the flyback transformer...If the transformer is not being driven properly by the H output/osc system there will be no heater voltage to the HV rect. Most HV rects are hard to impossible to see any glow from even when working properly...So don't worry if it is dark. If you can get 1/4"+ of arc from the top cap of the HV rect, but no arc from the HV connection to the CRT then the HV rect is suspect. You can look up the data sheet of the tube and check if the heater filament is open with the ohms function of a DMM. Substitution with another tube is also a valid test.

If you don't get an arc from the to cap of the HV rect then make sure you change all caps in the horizontal output and osc sections as well as the B+ Boost rail. then check resistors in those sections and check voltages.

The set is a little harder to troubleshoot because the CRT is mounted separately in the cabinet. I never give it a second thought because I can use a test CRT.
The OP would have to remove the CRT from the cabinet and have it on the bench with all the connections made, as the yoke plug has to be in to complete the B+ circuit.