Reliability problems with MIDI Controller

[UniCav]

I've been using Freestyler for a year or so now, versions 3.5.2, 3.5.4 and now 3.5.5 with an Akai MPD-18 control pad. I keep the pad on my keyboard during shows, the laptop sitting backstage, and have my sequences and override buttons laid out on it so I can control the Chauvet SlimPAR 64's patterns and speed and the color of the ADJ Mega24-Pro's we have uplighting our band's banners. I've had problems losing all control via the pad that seem to continually get worse. Everything will be fine until some random point in the show when I'll tap to stop the sequence and go to static lights between songs and I'll have no control anymore. Originally I suspected the USB cable so I bought one with a repeater to increase the reliability. Still having more and more problems with it. When it happens I have to restart Freestyler and usually it immediately starts working again but then fails again mid-show. Sometimes I have to kill Freestyler, unplug the pad and reconnect and start over again. But it never seems to keep working. Any thoughts on whether this is a problem with the pad, controller or possibly still the cable even though I've been through 3 different ones? Until I figure this out I've quit using DMX entirely and just have the lights running independently on sound.