7704A Mainframe Panel Lights No-Op


k6whp
 

(seems like this guy is rebelling against me or is deteriorating.)

The panel light for the controls in the front middle of the mainframe are dead. That is the button lights for the Vertical and Horizontal Mode buttons have gone out. (Scope still works.) Additionally, the A and B trigger Source lights no longer work as well. Before some worked and some did not. Now the whole thing is dark.

In looking at the service manual, I stumbled onto page 6-3 and note that there are four boards ("board 11", "board 12", "board 13", "board 14" which are Vertical Mode, Horizontal Mode, A Trigger Source, and B Trigger Source respectively.) and each of these is supplied with a "+5V Lights" source from the Calibrator Board 10 but the schematic shows no originating source and I have not been inside the uni yet to see what's what.

Anyone troubleshoot this problem and can offer advise and information?

Thanks in advance.
--
William, k6whp
"A friend told me to cheer up, things could be worse.
So I cheered up and, sure enough, things got worse!"

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