Mackie SRM 450 powered speaker

[N Cook]

How to separate the 2 main body parts.
I have to get to the speaker and have so far only removed one screw.
They are 2 inch long, twin start, that bite too much in the bulk of the
plastic.
I'm aware of this situation before, in other kit, and the screw shank
snapping due to the excess torque required to undo, not just the first turn
but perhaps half the thread length. Previously I've heated the head of the
screws with a soldering iron to partially soften the plastic , then when
extracted, drill out the plastic a little.
But these are recessed 8 inches down.
So is it a matter of the shaft of a long philips screw driver with the
plastic handle removed , replaced with something metalic and a soldering
iron heater slid over the shaft to heat the recessed screw.
Anyone tried extending an impact driver to break the binding ?
Any other ideas ?

 

[N Cook]

How to separate the 2 main body parts.
I have to get to the speaker and have so far only removed one screw.
They are 2 inch long, twin start, that bite too much in the bulk of the
plastic.
I'm aware of this situation before, in other kit, and the screw shank
snapping due to the excess torque required to undo, not just the first turn
but perhaps half the thread length. Previously I've heated the head of the
screws with a soldering iron to partially soften the plastic , then when
extracted, drill out the plastic a little.
But these are recessed 8 inches down.
So is it a matter of the shaft of a long philips screw driver with the
plastic handle removed , replaced with something metalic and a soldering
iron heater slid over the shaft to heat the recessed screw.
Anyone tried extending an impact driver to break the binding ?
Any other ideas ?

whoops
just as i'd found a soldering iron heater to slide over a long philips I
decided to see if there was access via the front grill, bolts without spring
washers so surprising none were actually loose, accessible from the front.

No apparent reason for failure of the speaker and cold tests of the driver
trannies look ok, not shorted to DC rails.
Was working normally , not overdriven according to the owner . Then next
power up there was horn output but no bass driver, just as though a wire had
come loose, no big thump or noise.