My cat knocked my 6G15 reverb off of a height of about 5'. Afterward, the reverb effect was much less pronounced than before... with all controls maxed, you can make out some reverb, but not a normal amount. I'm pretty handy, so "simple fix," I thought. I was wrong. Here's what I've done. Tried 3 separate original Gibbs/Hammond tanks with the correct impedance ratio, including one known-good from a Super Reverb whose reverb was working well. Tried at least one additional known-good tube in each position. Swapped reverb and input/output cables. Verified that the locking mechanism on the tank was disengaged. Checked all voltages listed on the schematic/layout; all checked as normal Visually inspected all connections inside unit (nothing amiss). Tested for continuity on all connections for wires that run under the eyelet board (all good). Cleaned and re-tensioned all tube sockets. Checked footswitch jack and tested both with footswitch engaged and disengaged. Verified that the guitar and amp were plugged into the correct jacks. ... At this point, I'm not sure what else to check for. The only thing I can think is... partial short in either the primary or secondary of the OT? I've never known that to happen as a result of a fall from height, but I suppose it's possible. Any ideas/thoughts are appreciated. I'm not really used to something happening with a Fender amp-like product that I can't diagnose and fix myself, but this one really has me stumped.