I was playing last week and something odd happened to my rig. I generally work through a Mesa Boogie Lone Star Special. This is a wonderful sounding amplifier with a lot of great features including one that I use a lot: solo mode. Solo mode is engaged through a two-button foot switch. One of the buttons triggers the first and second channels of the amp and the other button adds a boost to output of the currently selected channel. Very handy in live sound situations where you want the solo to cut through. I trust sound engineers but sometimes they do not always react in time for the start of a solo line.
Last week the solo mode would not engage. Of course I followed the usual routine: press button, no solo mode, press button, no solo mode, press button, no solo mode. I lost count of the number of times I repeatedly pressed the button. What could be wrong?
Troubleshooting on stage is not very productive so I waited until I got the amp home. I have found over the years that the best way to troubleshoot is to deal with the basics first. And so I focused on the foot switch and the cable that connects the footswitch to the amp. Fortunately, I began with the cable. A very basic Tip-Ring-Sleeve cable. The continuity meter showed green on Tip and Sleeve but no joy on Ring.
I removed the jacket to take a closer look and sure enough the contact to Ring had separated. Likely due to a cold solder. I stripped the wire and resoldered the contact.
Everything works. I can solo again.