Mark III blue stripe: where's R131?

[Whoopysnorp]

I've procured the pot I need to do the R2 mod to my Mark III blue stripe. All the instructions I've seen say that R130 gets snipped out and the pot goes between that trace and one end of R131. Well, my Mark III doesn't seem to have R131 at all. Was that resistor left out of the blue stripes on purpose?

 

[Whoopysnorp]

That thread is precisely the reason I posted this one. The resistor that is in the R131 position in those photos is M.I.A. on my amp.

 

[Whoopysnorp]

Nobody knows?

 

[silentrage]

I'd like to know that.
R131 is missing from mine, the part of the PCB where it's supposed to be looks very clean, doesn't look like something was "snipped" out of it.
On the other hand, my r2 and lead volume are pretty much balanced, R1 sounds noticably louder, but if I engage a clean boost on r2 and lead all 3 channels balance, so maybe what I need is a R1 volume mod?

 

[phyrexia]

Do you have a 100w or simul Blue? My 60w blue had a R131.

 

[silentrage]

SimulBlue here.

Please keep in mind that when I play the amp at somewhere between bedroom and rehearsal volume, I can get all 3 channels to balance perfectly with a boost on R2 and Lead.
This may change at higher volumes, if I ever get the chance to test that out I'll report back.

Maybe this is a feature of the blue stripe simul that allows better channel volume balance?

 

[phyrexia]

My blue stripe had R131 present.

 

[silentrage]

Your 60w?
Maybe I should call mesa and ask.

 

[silentrage]

Ok so Mike B says to do the r2 volume mod on a blue stripe, you just snip out R130, and connect the 2 spots it used to occupy to the tabs on a 250k pot, doesn't really matter if it's shielded wire or not, sounds easy enough.