My Wahl 9918 Groomsman Beard and Mustache Trimmer has admirably performed its beauty duty for many years, but the time came when the battery just wasn't holding a charge any more. Most people would just put the trimmer in the trash and buy a new one, but I figured I could repair my Wahl and save some money.
I opened up the Wahl by popping off the black plastic faceplate with a tiny flathead screwdriver, which revealed two screws. By removing the two screws I was able to easily open up the unit, revealing the guts of the device.
|Backplate off, Revealing the screws|
The internals are rather simple: a motor, a simple circuit board, a switch, and a NiCad battery pack soldered into place.
|The Internals, with new battery pack|
I decided that the battery was no longer good, so I worked to replace it. I bought two NiCd Rechargeable AA Cells with Solder Tabs. The solder tabs are key - they make it reasonably possible to solder together a new battery pack
To create a new battery pack, I used some electrical tape to wrap together the two new cells, in plus-to-minus orientation. Then I used a trusty soldering iron to solder one of the plus/minus tables together. I pulled the foam off the old battery pack and stuck it onto my homemade pack.
Then I unsoldered the old battery pack from the Wahl and soldered the new pack in, ensuring that I kept proper polarity.
After, I cleaned up some corrosion on the switch with a pencil eraser and an emery board, and reassembled. A little test proved good, and so I plugged in the trimmer and let it charge overnight.
Now the Wahl works like new! It runs perfectly and charges perfectly to. It continues to provide me with a beautiful beard, 12+ years running.