chuc - you may need to replace the CapXon 1000 uf 10v capacitors in the unit (If this is what is in the 15" unit) This fix was for the same type of problem on a 37" Polaroid. I found this fix and thought you may find this useful. This is from user Stivo "This has worked for me, I am no technician so I can't say that it will work for you.
Click here for information on caps. Or hereIf you try this it is at your own risk!
Defective Parts:2
CapXon 1000uf 10v caps.
Replaced Parts:2
Off brand 1000uf 16v caps. (the closest match my local supplier had.)
Once unplugged and flipped over I removed these three screws to access the control box.
Carefully pry up and pull back on the vented cover.
With the cover off I removed 3 more screws and again carefully
pryed up on the control box cover to expose the inside.
Circled is the location of the bad caps. (This is an after picture. I didn't take any
pictures of the caps still on the board.)
Press your index finger over the tops of the 2 caps and feel for a bulge. Good caps should be
sunken in. Bad caps ballooned.
These are mine removed
In order to
de-solder your caps you must unplug all connectors and remove the 4 screws holding down the board. Be very careful!, and only touch the sides of the board. Wear an anti-static band also.
Once removed pull of the plastic shield underneath the board. Be careful and save it, YOU MUST PUT IT BACK.
Carefully
de-solder the old caps. Replace with new caps.
Note the polarity This is very important! On the board look for the + sign. That is your positive. The longer lead should go here. Take your time and verify This step.CLICK HERE FOR CAPACITOR POLARITY(sorry no pics on the cap removal and install I wasn't positive that this would work so I didn't think about taking any.)
Reverse the procedure to put your set back together.
Now plug it up and hope it works for another year!
Curse Polaroid and vow to never buy anything from them again!
It works again"