TE TA200 question

[3chordmike]

Hello Trace Elliot Forum Folks...I'm fortunate enough to have a nice TE TA200 Acoustic Guitar amp, probably from around 2012-2014.  The left side two speakers no longer output sound, but the pre-amp outs have good signal, so I suspect the left side power amp (unit supposedly has two 100 watt class D amps internal) has failed, with the expected bad caps or transistors.  My question is: I thought it would be a fairly straight forward job to open up the back to examine/pull out amp(s)/diagnose/repair, but after removing the apprx 9 wood screws apparently holding the back plate to the cabinet, Surprise... there is No give or looseness observed.  I kind of assumed one would carefully slide out the panel with its attached PC board(s) to get to the insides.  I don't really want to take a pry bar to it, as I'm thinking there may be a secret I'm missing here.  There are two screws on the bottom of the cabinet, so I loosened them a bit to see if they allowed for some movement of the back plate...nope.  I also loosened the two screws per side of the cabinet that obviously hold the pre-amp section in place, but again, no luck.  Has anyone opened up the back on one of these amps and could impart some advice?
Regards,
Mike C