R2 on Mesa Boogie Mark iii doesn't work

[CrunchMaster94]

What is happening Boogie Board! I am brand spanking new to this forum so sorry if this is in the wrong place.

I just got a Mesa Boogie Mark iii and the clean and lead channels are soo sick! But when I pull the middle knob for R2 nothing happens, it just stays clean. I don't know why so I need some help, thanks!

 

[loylo69]

It may be related to a failure of the relay or the vactrols which are used for R2 switching.

 

[CrunchMaster94]

Would that be hard to fix? Or expensive?

 

[loylo69]

If it is the relay which failed, it is quite hard. You would have to pull the circuit board in order to desolder it.
If it is one of the vactrol, it's easier.

I think a qualified tech wouldn't charge you much. Pulling the PCB wouldn't be too much of a hassle for him.
Concerning the parts, a relay costs nearly nothing, vactrols are more expensive, but not that much.

 

[CrunchMaster94]

Alright thanks for info, I really appreciate it!

 

[McBarry]

Agreed its only a few likely cuplrit(s) or dry joint.
If it does nothing, after checking the pull-switch and/or the footswitch are actually working, my money says the relay isn't switching.. If it was and there was a failure downstream I'd expect a "no sound" or atttenuated sound condition.

For the relay to not switch it could be the relay, but equally it could be the low voltage supply to the relay.

FWIW, I had to replace the LV filter cap on my MkIII and the preamp board had to come up as it's soldered from underneath... NOT at all user-friendly.

From memory, took me a good half hour or more just to disconnect the damn thing.

It's not a fast job at all... PITA is a good description.. LOL


BTW, the relays are fairly specific from memory - Omron but I can't recall the model. LDR's are usually VTL5C1's but the R2 might be a 5C2..