Help! JR6 cutlass preamp system do not work

[ca8842]

in the last 3 days,when I played bent string notes,the pikups made buzz.
other times,it worked well.
I love the sound.

last night,after 2 hours of pratice,the system output signal was getting weaker and weaker.
Finally,there was no signal anymore.
switch pickup,there was no sound.
switch guitar cord,there was no sound.
chang bettery,there was no sound.

switch guitar,there was BIG sound.

then i know,the preamp system is dead.

this is the second time I see this thing happen on a JR6 cutlass.
last time it happen was last winter,my friend bought the JR6 RED from Authorized dealer.
but just in a week,the preamp system is dead.
and then my friend returned the guitar and change it to a JP one.

my guitar is a second-hand one,so the warranty is void.

Does anyone meet this before?
Does anyone has a schematic of this preamp?if I get the schematic,maybe I could fix it myself.

 

[DrKev]

Hi and welcome to the forum!

That the sound diminished over a period of two hours suggests it may not be the preamp or circuit board. Is there any possibility that the second battery you used to test was dead? Do you have a multimeter to test the battery voltages?

For the preamp schematics, Music Man will almost certainly not divulge that information as it proprietary trade information, but you absolutely should write to customer service and ask for their assistance in trouble shooting this issue. Remember to include the model and serial number of your instrument. See the links below.