Fixing my Wahl 9918 Groomsman Beard and Mustache Trimmer

Not everyone would bother repairing a $25 beard trimmer, but why not fix something for under $5 instead of spending another $25?

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.

In fact, even higher end trimmer and rotary shaver brands, like Norelco and Remington, can be repaired using a process similar to the one I used to fix my Wahl.  Read on to find out how.

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 holding a charge, 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.   You can also buy pre-assembled packs to repair Wahl, Norelco and Remington products with, for example, the battery packs found here.

To create a new battery pack using two cells, 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 tabs 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, 15+ years running.