The light is constantly on on my LR Baggs - elemejnt on board system in my Larrivee quitar

What make and model?

Simplest is to use the LR button at the bottom of the channel strips you want to send to the main mix. Make sure you set the gain for each channel in use so that the clip light just occasionally blinked then back off a fraction.
If you want to use sub channels assign the strip to the appropriate one 1/2 or 3/4 and the assign the sub to the main mix and bring the subs up.

The internal board is gone. You need to get it replaced, although may be cheaper to buy new PA Speakers.

Does it come up with DRIVE INIT or does it go straight to please wait???
I had a problem like this when i didnt eject the media properly from my PC. It would not turn off and just said please wait..... until finally i switched it off waited 5mins then turned it back on. If you can get your PC/MAC to see the drive you should delet the file you uploaded. Did you put the stereo file in the "2mix" folder of directly into the project folder?? To be honest The Fostex LR16 is a pain in the ****!!!

You are proabably getting regeneration. This is nothing more than feedback as these acoustic guitars are good microphones. Make sure the guitar CANNOT "hear" the speakers of the PA system. Crank the high frequency EQ for that channel all the way down. This is common when soundment decide they ALSO need to boost the high frequencies of the PA up when they shouldn't. Regeneration is a feedback that is below that to fully sustain, but will cause a ringing "tail" on notes.

I hate to say it but you probablly need a bigger hammer... grip the jack, not the fiddle, and put more force on the plug... they can initially be tight... I do NOT like carpenter jacks myself. They are too heavy. At the 1 cm point is where the plug has to displace the contact. Expect to put 1 to 2 pounds of force to get the plug in... SUPPORT the jack so the force doesn't go on the fiddle. Make sure to use a high impedance cord and preferably short, say 3 feet cord. The capacitance of a guitar cord heavily loads a piezo pickup reducing the high frequency component of the fiddle sound and distorting the waveform. The impedance of the piezo's are around 1 to 2 megohms. Looking on an oscilloscope I found that a guitar cable and amp input made the normal sawtooth violin waveform into peak like mountains. We are now using a short cord (2.5 feet) into a Line6 X2 wireless digital body pack. The link transmits the wave undistorted.

These pickups have a very high impedance so you must run into a high impedance input. Many amps expect low impedance guitar outputs and these piezo pickups just can't drive them.
We currently use an X2 wireless system which has over a 1.5 megohm input impedance which works well with these piezo pickups. Long guitar cables degrade the signal as well and running into a DI just won't work.

It is important to turn off the battery when not in use... they may have a switch OR often when you plug the guitar cable into the unit that completes the circuit to the battery. Another thing the 9 volt batteries are not the greatest. With continuous pwer I would expect the battery to last a couple days. Remember that the devices that have a pushbutton to alternately turn on the device DO still place a small current drain on the battery... For those devices REMOVE the battery when unit is be idle for a week or more.

In the first place you CANNOT connect your guitar directely to the snake ! You must use a DI box to convert the unbalanced output of the Baggs to balanced (differential) drive to the snake using either XLR or TRS cable. The DI should be driven as a HIGH impedance in and using "ground lift".

If the pots are noisy, lube sparingly with CRC 226 available in the electrical dept of Home Depot in a spray can with spout for about $2.70. Spray using the spout into the side where the leads go into the pot.

The volume pot is overly sensitive because you are overdriving the mixer at the other end. The trim on that channel of the mixer probably has to be reduced as well.

Intermittent problems cn be a real pain to find... BUT I want you to verify your use of the mixer and its connections as one can cause the output drivers to latch up due to ground bounce.

Make sure your outputs go to the power amps AND into balanced inout at the amps... either XLR or TRS connectors.

Make sure that the amps are POWERED from the same receptacle as the mixer... even if you have to run power back to the mixer. If you power the mixer from a different receptacle at the other end of the room, ground bounce of the safety ground MAY exceed the common mode drive of the mixer and cause the output drivers to latch up or even be destroyed!!!