Mark IV mods?

[Force]

It is time to have my '91 Mark IV rev "A" gone over and refurbed. I've owned the amp for five years now and it's just time to have her checked out and brought up to original specs so she remains gig ready and able to go another twenty years. The amp still works fine, but I suspect she has lost a little of the original vibe due to aging components, etc.

Does anyone know of or recommend any particular "mods" that I should specify over and above the routine stuff? Any input/recommendations are appreciated.

 

[Boogiebabies]

It's not the most mod friendly amp. I would get the caps replaced and hope that it survives that in one piece.
I would personally just change the two 220uf/300V caps on the power supply board and the two 47uf/100V bias supply caps.
If your tech is EXTREMELY good you can change the 30uf/500V caps on the main board, but it's a major ***** if you don't have
the proper de-soldering equipment. One blob of unseen solder on them and your entire HV supply is shorted to the chassis.

 

[Force]

It's not the most mod friendly amp. I would get the caps replaced and hope that it survives that in one piece.
I would personally just change the two 220uf/300V caps on the power supply board and the two 47uf/100V bias supply caps.
If your tech is EXTREMELY good you can change the 30uf/500V caps on the main board, but it's a major ***** if you don't have
the proper de-soldering equipment. One blob of unseen solder on them and your entire HV supply is shorted to the chassis.

excellent advice no doubt. I was thinking of shipping the amp to Petaluma...

 

[Boogiebabies]

95% chance they won't change the 30uf's then unless something is wrong.

 

[Force]

I appreciate the information. I am not a techie, just a player. Other than changing tubes, I don't have any tech knowledge; only good ears, and even the ears aren't quite what they used to be, too much loud music over the decades!!