All
I've come by a Sony 28FX20U (BE3B chassis) set, which runs but flashes the standy light to indicate error code 5 (video fault) and the picture is rather washed out.
I don't have the service manual but checked the tube base shows that the G1 votlage is missing. I note also that the 1kV on connector CN703 is not present, but due to missing components, it's clear that it's not supposed to be on this particular set.
The G1 voltage comes from the G1 control mounted on the tube base (PCB C). The diode D712 meters out fine, but there is no voltage at the G1 pins except for a negative blip when the set is first powered up.
I suspect the Line Output Transformer is defective. It's obviously rather tricky (dangerous) to try to examine the unrectified output to the G1 control from the transformer, so I can't easily prove whether it's the control or the transformer.
Any help most appreciated. Please email snipped-for-privacy@bigfoot.com in any reply.
Thanks and regards,
Colin