Something may have changed as the read across the ends of the diodes that feed that cap was 14.33 versus the recent read of 13.52, which may have been marginally OK to see something on the 12 volt side of the regulator unloaded even if less than 12 volts. Specs for the 7812 seem to show 14.5 as a minimum to attain a regulated 12vdc.
I don't believe a read of the AC going into the bridge was ever noted.
If the regulator is pulled, take an ohmmeter reading across the cap that read '0' volts. It should settle to be 2kohms or higher depending on the ohmmeter lead polarity after the cap charges. Unplug the power supply and let it set a while before doing the check with the ohmmeter.
Fenderguy..... can you get a look at the side of the regulator chip and confirm it does indeed say 7812? I found some information the someone 'thinks' it may be a 7809. The tube in the mic can be run at 12v or 6v depending on how the filament is wired. A 7809 seems odd unless they run the 12 volt filament at a lower voltage for some reason.
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