Mark III Footswitch Question

Hey All- I just picked up a Green stripe Mark III on eBay and the amp did not come with any footswitches provided. I noticed that there are actually 2 different ones listed in the online Mesa/Boogie store for channel switching the amp between all 3 modes. I have a basic Hughes & Kettner FS that I tried to get the Mark III to go between channels and it only worked on the rear FS jack to switch between R1/R2; it did not work plugged into the front panel jack to switch between Lead/Rhythm. I'm wondering if it is a problem with the amp or does the amp really require 2 different types of switches (providing what seems like a very similar function)? Thanks, JC.

Did you have the Lead Drive knob pushed in or pulled out when you tried the front panel footswitch jack?

I tried it both ways, no luck with either.

Do the channels all switch correctly with the front panel knobs?

Yes, all channels work perfectly using the pull knobs. I'm thinking that the 2 foot switches that Boogie offers have to be slightly different operationally otherwise why bother producing two completely different ones?

My blue stripe's foot switches are interchangeable.
Could this be an LDR malf?

How comfortable are you with pulling the chassis and working inside the amp's guts?

Not really, I'm more inclined to leave the hands-on tech stuff to the pros. I did notice that when the H&K foot switch is plugged into the front panel jack the LED is getting power, but the FS just not switching between Lead/Rhythm. The FS works great plugged into the rear panel jack and goes between R1/R2 without any problem at all. I'm really interested to know if the 2 foot switches that Boogie offers are exactly the same product with just different graphics to help things to keep from getting confsing or do they actually have something different operationally that may tie into the problem I'm having with the H&K foot switch. Fortunatley, I don't have any gigs scheduled for the rest of the month so I can probably wait until Santa brings both of the MESA/Boogie switches to my Christmas tree. I was hoping someone could just check their R1/R2 foot switch in the front jack and see if it functions properly switching between Lead/Rhythm. I'm really hoping that I don't have a faulty front panel jack. That leads me to my next question: Who do any of the folks here on the Board use as their Boogie tech guru in the NYC area? Any help is welcome and thanks for being willing to coach me thru some trouble shooting but I'm not that hands on in the tech way.

the mechanics of the actual stompswitch in each pedal is the same....the only difference is that the Rhy-Lead switch has an LED and associated voltage dropping resistor

you might have a bad front panel footswitch jack....or there may be something with the H&K switch that doesn't like the Mesa circuitry.

Try this....get a piece of aluminum foil. plug in a guitar cable into the front panel footswitch jack. wrap the foil around the free end of the guitar cable (which should short the plug tip and sleeve together) and see if your channels switch. that's basically what the stomp switch is supposed to do.

I'll give it a shot later today, thanks for the tip.
JC

acorkos said:

the mechanics of the actual stompswitch in each pedal is the same....the only difference is that the Rhy-Lead switch has an LED and associated voltage dropping resistor

you might have a bad front panel footswitch jack....or there may be something with the H&K switch that doesn't like the Mesa circuitry.

Try this....get a piece of aluminum foil. plug in a guitar cable into the front panel footswitch jack. wrap the foil around the free end of the guitar cable (which should short the plug tip and sleeve together) and see if your channels switch. that's basically what the stomp switch is supposed to do.

Click to expand...

Both MESA switches have the LED and appear to be identical other than the labeling. I have used a rhy/lead switch on the Rhy2 jack in a MkIII, with excellent results. I would say the problem is in the front panel jack or its wiring to the circuit board. If the LDR was faulty, I don't think that your "Pull Lead" knob would switch the channels. There is a white wire and a braided ground wire connecting the footswitch jack to the board, and then uses the traces in the circuit board to get to the LDR.

If you try the "aluminum foil" test, make sure that your "Pull Lead" knob is pushed in.

We'll I'm happy to say that the foil trick worked great! The amp switched from Rhy/Lead as soon as the foil was wrapped around the open end of the cable, so it just confirms that the Boogie did not like the H&K foot switch. I'll be sure to get the Mesa switch and I'll be off to the races! I want to thank you guys for helping me solve this one without the need to open up the chasis or get it to a tech. THANK YOU VERY MUCH!!!
JC

I'm glad it was that easy. Obviously, the Boogie switches are interchangable with each other, but not with the H&K for all purposes. Note to self .

The Mark III resistor has a 3300 ohm resistor in there. A Tremoverb footswitch, for instance, has no resistor. I noticed if I used the Mark III FS for the Tremoverb, the LED would light up but the channel wouldn't switch.

I guess the resistor blocks too much current and the Mark needs full ground continuity?