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Hello folks,
though I would share some info we discovered about a month ago with the Mesa Mark V. Here in Denver, we have a very low humidity & as a result much static voltages to deal with.
We started to see the Mesa MkV coming in with weird symptoms of 'my amp switches back to channel one all by itself or when I go to hit a switch on the pedal.
One of our techs charged himself up with static (easy to do here) & moved his foot to switch the pedal & as soon as his foot just touched the pedal case, the amp defaulted to channel one.
he discovered that this particular pedal has nothing grounding the case of the pedal at all. It is basically floating. also the ground shield of the pedal cable is not ground but actually an active line.
He found the pin that is ground & grounded it to the case of the pedal with a hole & screw/nut. Also in order to ground the actual switches, he had to grind the paint off below the top nuts & move the star washers from under the switches to on top of the switches in order for them to get reliably grounded. You can't really do this grounding from beneath as each foot switch has a nylon washer on top of it.
I'll attach pictures when I get to the shop tomorrow.
There is also another issue with the rear jack pcb that needs to be addressed. this affects some switching of the effects loop as a result of some incorrect ground-sharing between jacks...that problem you won't discover until you need the effects loop.
I can't recall all the details about that as I am home getting ready for beddy by...I'll post that some other time when I'm at the shop... we have notified Mesa. they've already addressed the jack/ground sharing issue & will address the pedal issue, too. later, glen
though I would share some info we discovered about a month ago with the Mesa Mark V. Here in Denver, we have a very low humidity & as a result much static voltages to deal with.
We started to see the Mesa MkV coming in with weird symptoms of 'my amp switches back to channel one all by itself or when I go to hit a switch on the pedal.
One of our techs charged himself up with static (easy to do here) & moved his foot to switch the pedal & as soon as his foot just touched the pedal case, the amp defaulted to channel one.
he discovered that this particular pedal has nothing grounding the case of the pedal at all. It is basically floating. also the ground shield of the pedal cable is not ground but actually an active line.
He found the pin that is ground & grounded it to the case of the pedal with a hole & screw/nut. Also in order to ground the actual switches, he had to grind the paint off below the top nuts & move the star washers from under the switches to on top of the switches in order for them to get reliably grounded. You can't really do this grounding from beneath as each foot switch has a nylon washer on top of it.
I'll attach pictures when I get to the shop tomorrow.
There is also another issue with the rear jack pcb that needs to be addressed. this affects some switching of the effects loop as a result of some incorrect ground-sharing between jacks...that problem you won't discover until you need the effects loop.
I can't recall all the details about that as I am home getting ready for beddy by...I'll post that some other time when I'm at the shop... we have notified Mesa. they've already addressed the jack/ground sharing issue & will address the pedal issue, too. later, glen