ENGL Sovereign 100 repair!

  The ENGL Sovereign 100, what a nice sounding tube combo! It's a hard rocking machine, no doubt about that! The drive sounds are awesome and the 100 Watts of rock power on the Vintage 30 speaker can make your studio shake and treble. It's made in Germany so it's an expensive amp and maybe over-engineered, sporting many features.
  But all these features need space and this is were the problem begins. PCBs and their components are getting smaller and smaller and it's really difficult to work with. Also, there's more plastic on these components than even before.
 That's why this particular amp was having problem with one master volume pot that was all-plastic. Plastic pots tend to break and the only way to fix the problem, is to replace them. But, as I said, it's really difficult to replace a small plastic pot that's soldered with 5 solder joints on a thin, multi-layer PCB that's packed with parts.
  So, what I did was to remove the old pot and solder 3 short wires on the pcb (were the old pot was connected). Then, I bolted a nice 16mm Alpha metal pot on the metal chassis of the amp(were the master volume was located) and connected it to the 3 wires. It works like a charm! And now the pot is all metal and really easy to clean or replace in the future. So, I wonder, why didn't ENGL use metal pots in the first place?  ... Would metal pots reduce the profit margin (on a 2000Euro amp) by that much?
 Finally, when the pot was fixed, we changed the tubes with quality JJ/Tesla ones and biased the power amp to ensure it performs perfectly! Now it's rocking again!

Here are some pictures taken during the repair: