Many Logitech products look alike, but use different parts. To ensure that you get the correct replacement, you'll need to find the part number of your Logitech device and match it to one of the numbers displayed in italics below the descriptions at left. This number will be in the format of P/N:8xxxxx or 8xx-xxxxxx, and can be found in the following locations:
Bottom or rear of device
Underneath battery cover
Behind foam ear cushion
Go here and put your number in: http://buy.logitech.com/store/logib2c/en_US/DisplayCategoryProductListPage/categoryid.13931700?WT.ac=sc|downloads||dd
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Here how to replace it:
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Carefully peel off the orange back of the keyboard. Do not tear it as we will replace it during reassembly.
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Remove the 19 screws. 19th screw is under the black Bluetooth sticker under the charging pin.
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Pry open the keyboard.
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Replace the battery.
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Sqeeze the keyboard back together making sure the on/off switch functions correctly.
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Looking at the glue patterns on the gray side of the orange backer mark each screw.
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Drill all marks with a 5/16" drill bit. This will allow the keyboard to be taken apart without peeling off the backer next time.
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Spray the gray side of the backer with spray adhesive (3M Spray Mount in my case).
Many Logitech products look alike, but use different parts. To ensure that you get the correct replacement, you'll need to find the part number of your Logitech device and match it to one of the numbers displayed in italics below the descriptions at left. This number will be in the format of P/N:8xxxxx or 8xx-xxxxxx, and can be found in the following locations:
Bottom or rear of device
Underneath battery cover
Behind foam ear cushion
Go here and put your number in: http://buy.logitech.com/store/logib2c/en_US/DisplayCategoryProductListPage/categoryid.13931700?WT.ac=sc|downloads||dd