After some heavy use last year during tax preparation, the internal fuse blew. So I went to get a replacement. It took some time to find out how to open up the shredder, but eventually I got the job done and the shredder worked again….
…until I prepared this year’s tax.
The fuse blew again, and getting the shredder open just consumed so much time the first time that I decided to replace the fuse with a resettable circuit breaker.
I could have just bought a new shredder and I really was on the verge, but I really love my Mailmate.
It also saves about 37 bucks (the price of a new shredder minus the circuit breaker) and it is environmental friendlier to repair than to replace.
So this time I’ll show you how to open the shredder and how to replace the internal fuse with a circuit breaker.
If you have other appliances including a hardwired fuse, this instructable may help getting an idea on how you can improve the affected appliance.
- Be careful if you follow this instructable and only do this if you are familiar working on electronic circuits.
- The shredder runs on AC, so ensure to pull the plug before opening the unit.
- The circuit board has some capacitors which could carry load. If not handled properly you run the risk of an electric shock.
- When handling the internals of the shredder, be careful with the blades inside to prevent cuts.
- Also, the sticker on the bottom of the shredder’s top indicates that the unit is not user serviceable.
- Do not wear your best clothes. The gears inside the unit are lubricated with some nasty grease.
If you follow this instructable anyway, you do so at your own risk.
Step 1: Tools and supplies
- Soldering iron
- Desoldering pump
- Heat shrink tubing
- Cable lugs
- Electrical pliers
- Cable stripper
- Circuit breaker (5A as per PCB, anti-surge type)
- Electric drill
The screwdriver must be long enough to reach the screws which fasten the waste bin housing to the shredder top (about 6 inch, maybe a little more).
The screw heads are all Phillips recessed heads. As I couldn’t find a screwdriver with the appropriate length, I used a regular flat head screwdriver which was long enough and filed the size of the blade to fit the screws.
The cable must be long enough to connect the main board with the circuit breaker. I used a cable with a length of about 12 inch and later shortened it to the appropriate length.
You can use single conductors, but as space is sparse within the shredder head, I opted for a two-core cable which makes routing the cable through the unit easier.
The wire cross section should be similar to the mains cable’s cross section as it has to carry the same current.
The internal fuse is rated at 5A. Unfortunately, I couldn’t get a circuit breaker with the same rating. So I bought one being rated at 6A. I assume that this will still work in the long term. It’s at least better to give it a try (in my opinion) than to open up the unit every time the internal fuse trips.