|
After the bad weather and some overtime at the job I finely got back to the Philco. Here is what I have done since last post.
The 4.7 ohm 1B3 filament resistor was 5.4 ohms and the 680K anode resistor was just over 700K. changed both with no change in problem. The horizonal grid drive is and exact match to the schematic the grid and screen DC voltage are right on and the boost voltage is almost perfect at 355 V and the pulse across the yoke winding is a perfect match to the schematic just a little low in amplitude 1350 V peak to peak the DC resistance of the yoke is correct also at just about 15 ohms. The most HV I can get is about 6K with no beam current and everything else peaked for maximum voltage. When the brightness is turned up just as it starts to light up the HV starts to drop. also checked the video and DC voltage on the CRT and they seem to be ok.
So now I am grasping for straws the 1B3 socket is kind of crusty along with the stand offs so I am going to change the socket and stand offs incase they are a little leaky very little hope that this will do anything. I have also swapped out the door knob capacitor with no change.
Any suggestions would be welcome.
|
02-10-2022, 05:42 PM
Threaded Mode