Here's the main support page for your unit in case you need the User manual or other documentation:
You may need ADOBE READER installed on your computer to read the USER MANUAL - PDF documents.
You can download this free at WWW.ADOBE.COM
Click on the DOWNLOAD ADOBE READER button on right side of the ADOBE home page when you get there.
Assuming the warranty is expired, you should have no problem disassembling the unit enough to access the speakers with just a phillips screwdriver.
Normally you just lay the unit screen side down on a soft flat surface like a bed. Just make sure nothing will gouge or scratch the screen.
Then just remove screws for the stand and pull it off (see page 2 of the Online Owners Manual).
After that you can remove all the screws from the back panel and remove the plastic enclosure.
You should be able to access the speakers from there.
Here is a link to some spares from EBay:
I didn't actually see any speakers for your exact model, but the online selection changes constantly so you may just have to get lucky and spot one that will fit.
The other option is to just go into your MENU and turn the speakers off. Then just use the rear outputs to feed into a home stereo / home theatre system for your audio.
Please comment back here to this page if you have any questions, have difficulty accessing the links, or just require further general assistance and I will respond as soon as I see it.
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Thank you very much and good luck.