I've had 2 gigs so far, where my SVT VR would stay in standby.
The first time, I didn't know what had caused it, so in TB fashion, I posted a thread asking about it. A fella named Johnk_10 had mentioned a mod, that he had done to his VR.
Link to his page on this (he's more detailed with the info on it): http://johnkvintageguitars.homestead.com/SVT-VR.html
Apparently, if the voltage is under 112 volts, she won't even come out of standby. After the second time at a gig that happened to me, that was it. With a few more questions I asked John, I was ready to do this.
First off, and very important, I needed to discharge the cap. Set up my rig in the living room and got it all hooked up.It was told to me that one way to discharge it, was to power it on (of course for a minute or so, take it out of standby and unplug the power cord, while playing the bass, it fades out, distorts, etc, then leave it for about 10 minutes or so. That would at least take any of the "lethal" voltage from the caps and leave a few volts or so.
After taking the amp out to my shop, I would need to make a "Y" cord first, so I got 2 male connectors and a female connector. Ok, so I cut 2 short lengths of solid core 16ga copper wire. Soldered that up.
I took the screws out of the bottom, that holds the chassis to the enclosure, left one in and took the last one out on the edge of the table (sitting flat).
Then, I took the back grille off:
Once you take the connections off the fan, I put this aside. Not pictured: I also took the chrome corners off the lower back side.
I then carefully slid the chassis out of the back and disconnected the 2 cable plugs. Admission of guilt: I did leave the tubes in, when I did this, but I did not move this around too much.
Once I liberated the chassis, I flipped it over (The transformers sit a little higher than the tubes, so the tubes didn't touch the tabletop. The small circuit board on the upper lefthand side is the one we're looking for.
I cut the wire ties, that were holding the wires all together.
At this point, this is where the "y" cable come into use, I unplugged the yellow wire @ "J-26", connected it to one of the male connectors on the y and unplugged the black wire from "J-27" to the other male connector. I plugged the female connector to the "J-27" on the circuit board. Then I wire tied it back up and re-assembled it back together.
Took it back into the house, plugged it back in and what do you know? It worked. So, Johnk_10, you da man!