1978 fender Pro reverb came in, with the owner thinking the reverb tank may be out.

After the initial labs, the cathode cap to V3 (reverb driver) was bad. The tube in the V3 slot was a 12AX7, rather than the 12AT7. All but one of the electrolytic capacitors were original, so we’ll swap them all out, put in a new 12AT7, clean the pots and board (the preservative has a habit of becoming conductive), and we’ll take it for a test drive. The power cord was replaced (thankfully) and all else seems OK.

After the initial inspection, two tubes are shorted out (one of them being a 12AX7, not the 12AT7 required). The fuse was also a 15A….way too much for this amp. I’m checking if more circuits fried. The normal channel works, but nothing from the vibrato channel …more to follow.