Strange Road King II Effects Loop

[Treachery]

For a long time now, I've been battling my RKII's effects loop.

I run an Ibanez Tube Screamer up front and have an MXR Carbon Copy in the loop. Channel 4. That's all.

I play no effects on rhythm and turn on/off Loop 1 (channel 4) via the Mesa pedal when I solo.

All the other effect loops are turned off except Loop 1 on channel 4.

When I plug in the a patch cable to the effects loop, volumes drop dramtically. I turn up the volume and master controls to 1 o'clock and the volume won't even fill my living room. You can also hear a hum as if a chord need to be plugged in. The dummy plug is plugged in the middle and I connect the head to a 4x12 standard rectifier cabinet.

Fed up, I connect to the channel 4 Loop 2 effects look. Guess what? It works! I can turn off/on the effects loop via the Mesa pedal and the volume is proper.

The strange thing about is that Loop 2 is switched off at the amp!

I will be taking my RKII to the amp shop to have it looked at.
How can it work when the effects loop is on Loop 2 (channel 4) and at the same time, Loop 2 is turned *off* via the dip switches in the back?

 

[TheEternalDance]

Treachery -

Did you ever find a solution or explanation for this behavior from the amp shop?

My RKII just recently started exhibiting a very similar behavior. In the past, my rack fx were all run through either FX1 or FX2, and on/off via the RKII footswitch was fine. Recently though, levels drop so dramatically in both FX1 and FX2 it is inaudible. I have been getting by using my FX up front, but would rather them after the 12AX7s.

I have ruled out all cables, tubes, and fx units, but have yet to bring it in to an amp shop. Did the amp shop find something weird with your amp?

 

[TheEternalDance]

Apologies -

Thought I had checked all sources of error, but discovered it was a bad 12AX7 after all. Time to get some new glass!

 

[sleepingtiger]

I had a similar problem with mine & it turned out that for some reason & had to work the loop switch on & off a couple of times & everything was fine.

Tony