How I revived a dead electric razor

This is the first time for me to try and publish about one of my little hacks; unfortunately I am writing this only after all the work has been done for months now, so I cannot really have a walk-through for this. But I am pretty sure you won't need it anyways, as this was very, very simple.

Electric nuances

If you have an electric razor, one of those rechargeable ones, you already know that one of the most annoying things is the blades, and this because they are so unbelievably expensive that sometimes it costs less to just go and buy a new razor itself. Yet, it always so happens that your blades die right when no discounts are available anywhere.

The other nuance with any rechargeable gear is that - sooner or later - the battery cells will die. And they usually do after you bought the new blades.

If you followed me so far, then you guessed already that I found myself with mint new blades and dead batteries that didn't want to keep their charge for more than 10 minutes.

First fixup

The first fixup took me a bit; after disassembling the razor, some googling and a quick trip to the local electronic store, I ordered two new AA cells online, which arrive a week or so later in my mailbox.

Few bits of soldering iron and the razor was back and ready to work, with actually a 30% increase in charge retention (larger cells that originals). Blades became dull, but no question: just got new ones, voila a big bright smile at every shaving.

That didn't last too long though...

Disaster strikes

Ironically, one morning, batteries just wouldn't spin the blades anymore. The charge LED was just blinking red, and no apparent juice in the cells. Did my new cells just die?

Armed with patience, a screwdriver and a multimeter, I disassembled the razor once again and started measuring around. To my surprise I was reading a very healty 3V across the serie. A little puzzled, tried once again the charger, but nada: the motherboard was just blinking red.

That could mean only one thing: the motherboard failed...

I took a moment to analyze the situation: I had a razor with brand new blades, relatively new cells, and no way to use it because the motherboard apparently died.

Should I just give up to evidence, throw the thing away and walk to the local store for a new razor?

Second fixup

I looked at the motherboard, and it was evident to me that the only function for it was to charge the NiMH cells, inform me when they were to be recharged again, and to drive the on/off via the front button. Do I really need the board for the razor to work?

The answer was obviously no. If you don't plan on using the builtin charging, then all you need is 3V to go straight to the motor, and that's it.

I first thought to straight wire the electric charger lines to the motor, but immediately realized that it was pushing out 15V (some should explain that to me...). No way to make the wireless wired...

Major surgery

Only option was to turn it into a battery toy, which I did. This frankenstein surgery wasn't too bad.

What did it take? Battery holder for 2 AA batteries, some wire, pair of scissors, cutter knife, soldering iron, bit of care.

After cutting lose the motherboard, I had to cut the corners of the battery holder to make it fit into the body. As I had lost the power button, I needed another way to turn the razor on/off.

I decided to go for the "easy and ugly" route, which was to use the charging pins as the open switch: all I would need to turn my razor on would be to short those two pins and have juice going to the motor. A paper clip seemed a reasonably ugly device for this.

Happily shaving after

And that's what I basically did. I had some extra parts left, but until my blades become dull, I now have a perfectly working battery-operated shaver.

Open questions

This whole process left me with some questions:

• why do you need a 15V charger, when your cells only have 3V?
• why is it so complicated to replace dead cells on the razor?
• why do you need a charging circuit at all: why don't just make the razor AA operated?

About me

My name is Salvatore Ventura; besides thinkering around with dead electronics and bright LEDs, I cultivate my passion in photography (you can see some of my work here). I also love python programming, web services and gardening. Will I ever be able to marry all of these (and more) passions together? :-)