When I was playing around with the amp I found a really bad short in oee of the input jacks.   When I took a good look at the jack from inside the cabinet I discovered that years of use in the #1 input jack had caused enough wear that the crimped area that held the layers of the jack together just snapped apart one day.  If you look carefully at the photo below you might see where it just fell apart.    If you look at the photo below it is the jack on the left that is broken.    The jack was desinged to function as a switch so it was not a typical jack.  Fortunately the name of the manufacturer was visible and I was able to locate an exact replacement (Switchcraft Part # 13E).   This was a little bit of a pain because there were several resisters that had to be be fitted back and there was no room to do it in place.   The only way was really to pull out the two jacks as shown and desolder and solder back the resisters in the same locations.

I’ve heard of people getting shocked by a vintage tube amplifier that was ungrounded and the 2-prong chord looked like it had seen better days.   So I deicided to add a new 3-prong grounded plug.    I used an existing ground location which was a bolt for the transformer.   You can see it in the lower left of this photo.

The only real difficulty was that the new wire diameter was slightly thicker than the old wire and the gromet that holds the wire in the case was almost impossible to press back in.    My solution was to take a hot soldering iron and melt the inside of the gromet to create a little larger opening and a bit more space for the wire.  It took a couple of attempts but eventually worked and clipped into place.