Intro: How to Repair a Moleskine USB Book Light
I bought this Moleskine Rechargeable Booklight and found that it worked great until the battery went dead and then when I plugged it into a USB port to charge it showed that it was charging but no matter how long you left it charging it would not take a charge and never worked again (unless you left it plugged in).
I did a search and found that this is an extremely common problem with this particular light. Here are some product reviews on Amazon.com saying how badly this thing sucks.
I really like this booklight and so it was a serious disappointment that it has such a design flaw.
So I decided to take mine apart and figure out how to fix it. I will now show you how to fix yours.
You will need:
- precision screwdriver set
- soldering iron
- wire clippers
- double-sided tape or hot glue gun or superglue, etc.
- electrician's tape
The fix will cost nothing and only take about 10 minutes. This is well worth it considering how nice the booklight is and how it originally costed around $20.
Step 1: Disassembly
Pry the plastic cover off the front. You will find that it is only held on with double-sided tape.
Then use a precision screwdriver to remove the little screws so that the mechanism comes out.
Step 2: Finding the Problem
First I had to figure out what the problem was. So I plugged in the unit to a usb port and then used jumper cables to verify that the lights work when the power is being supplied to the positive and negative rails on the bottom of the mechanism.
So the problem seemed to be that the battery is not being charged. It could be due to a faulty electrical component like a burned out surface mount resistor or something blocking current from getting to the battery from the usb.
To test this hypothesis I removed the plastic from the leads on the battery and connected the jumper cables directly to the positive and negative on the battery. Note that the "charging" indicator light will not come on. After a minute or two I disconnected the jumper cables and the light worked normally. Hence the problem is power is not getting to the battery from the USB input.
Step 3: Fixing the Problem
The solution is to connect the positive of the battery directly to the positive rail coming from the USB. That way it will charge directly from the USB power without going through the internal circuitry. However, this means that the "charging" indicator light will always be on since the battery is always connected to the USB power rail. Hence we first need to cut one of the leads (it doesn't matter which one) of the blue indicator LED. You don't need this indicator LED anyway since if it is plugged in it will be charging. If you aren't sure whether it is plugged in correctly or not, just turn it on. If it works then it is plugged in right.
In the first picture I show where to cut this.
Then you have to solder the positive (red) lead from the battery to the positive USB rail. The second picture shows how to do this. A good method is to heat the insulation on the wire and then pull it apart a bit exposing bare wire, then dab a drop of solder between this and the rail below.
Step 4: Finished Soldering Job
In these pictures I show better quality closeups of the finished fix. You can see the cut LED wire and the soldered battery lead.
Step 5: Putting It Back Together
Finally use some electrician's tape to cover up the battery terminals replacing the plastic you removed earlier.
Then put it back together, and stick the cover back on with glue, or tape.
Step 6: Finished!
Now you are done! It will now charge from a USB port and it will work properly.You should only charge it for 15 minutes or 1/2 hour to get a full charge. Note: here is the lithium polymer batter that is used you will be charging it at slightly over the nomial voltage and charging current which may reduce the battery lifetime (but it is still better than a lifetime of zero which is what it had before right?) Don't charge it for longer than 1/2 hour to avoid it getting hot (although mine never got the slightest bit hot even after charging for a long period as a test).