Mark IV footswitch switching issue help

[techlectic]

With my amp sitting in my living room, one day I no longer had channel switching with my FU-3 footswitch. No fiddling with the cable, the connections, or the switch on the back had any effect. The switch on the back still works, but not the footswitch. I found a post that said that the problem was fixed by replacing the 3 ICs in the footswitch, so I did that, but that didn't fix the problem. I read a post that said that the 3 ICs were also in the amp, and replacing those as well fixed the problem for that person. But I only see one of the same ICs on the board in the amp. I'm a little frustrated by the footswitch not being included in the schematic I have.

Can anyone help? If a footswitch can just go like that, I figure it must have happened to other people. I do not want to take this to a repair shop if I can help it.
thanks

 

[mandoismetal]

I haven't heard of an FU-3 just giving up like that.

However, I've seen plenty of other electronics just stop working.

Let me ask you a couple of questions first. I know these questions are rather "basic", but geeks like me will often overlook the simple things and will go for the more complex solutions first.

Is the knob in the back of the amp set to the FTSW position?
Is the cord to the FU-3 in good shape (not frayed, torn, etc)?
Unplug the amp from the AC mains and "turn it on"-this is an old computer tech trick. Sometimes capacitors become "overcharged" and start causing abnormal behaviors in electronic devices.

I hope you're able to solve your issue!

 

[techlectic]

Yes I tried all the basic checks before looking for a solution online and then ordering the ICs. All the channels work with the knob on the back but not with the footswitch with the knob set for it. I had a Mark III for a long time and I've had this Mark IV for more than 5 years. It hasn't been out of my house for at least a year. The footswitch and cable have suffered no abuse in my hands.

 

[mandoismetal]

I'm sorry to hear that.

Have you tried using another FU-3 (if available/possible)?

I really hope you're able to find a solution!

Worse comes to worse, you could always use a custom foot switch like this one:

http://voodoomanswitches.com/component/page,shop.product_details/category_id,1/flypage,shop.flypage/product_id,340/option,com_virtuemart/Itemid,1/vmcchk,1/

 

[Civgeek]

This just happened to me a few weeks ago. Turns out there were a couple solder joints in the Foot Controller that came loose.