Uugh! Footswitch woes!

[boogietone]

My MKIV's footswitch is acting up. Doesn't want to switch out of Lead w/EQ. It will after a while of randomly pressing buttons. The footswitch is from 1991 I think. Guess I should order a new one. Tomorrow I'll spray everything out with Electrowash and see what happens.

 

[MJ Slaughter]

I've heard of others here with a similar problem that turned out to be a couple of components, don't remember what they're called, that controll the switching. They may be called LDR? Little device on the PCB with 4 legs. Sorry don't remember but if you search around you might find something. I know that Monsta-tone has changed his out before.

 

[Blueracer]

Take a look at this thread.

http://forum.grailtone.com/viewtopic.php?f=3&t=30607

I was able to help pabloguitar work through his footswitch issues. If you can use and have a voltmeter and can solder reasonably well I can help you. I am pretty sure your problem is less involved than pabloguitar's was. All in all it took about $10 worth of parts to fix his problems. Compared to $295 for a new footswitch, if Mesa still sells them, or $100+ for an ebay footswitch I think we did pretty well. If you don't have the skills indicated it may be best to take it to a tech assuming spraying the stuff on it doesn't fix it. Let me know if you want to work through this.

 

[Tfunk Ian]

I've heard of others here with a similar problem that turned out to be a couple of components, don't remember what they're called, that controll the switching. They may be called LDR? Little device on the PCB with 4 legs. Sorry don't remember but if you search around you might find something. I know that Monsta-tone has changed his out before.

I had a similar problem with my Mark IV foot switch (I couldn't switch to R2). I found the problem to be the little Logic IC chips that are found in both the footswitch and in the amp. First, I replaced all of the Logic ICs in the footswitch and that didn't fix the problem, so I replaced the ones in the amp, and bingo, that did it. It was a pretty easy fix, no soldering required or anything like that. You just pop out the old one and pop in the new. I would say open up the footswitch and get the model numbers of the ICs, they are exactly the same in the amp as they are in the footswitch. Then order two of each of them (there are three in both from what I remember) from someone like Mouser or some place like that. The parts might cost you $20 or less, certainly cheaper then buying a whole new footswitch that might not solve the problem. I hope that helps. Also, I apologize if this is old news.

 

[boogietone]

Actually, I just bought a new footswitch. I'll try to repair the old one
though and recoup some of the money.
Thanks!