Mailmate Shredder - replace the internal fuse with a circuit breaker

Step 7: Reassembling the shredder

Replace the motor and shredder assembly into its recess within the housing cover.
Like described previously, be careful not to cut yourself and remember that the grease is very nasty.

Put the bottom part of the housing on the top cover.
Ensure that the circuit breaker and the cable running to it from the circuit board don’t get damaged. The space is very tight.

Replace the mains cable strain relief into its recess.

Ensure that the shredder output of the motor and shredder assembly properly aligns with the opening of the bottom part of the housing.

Fasten the bottom part of the housing to the housing cover with its 6 screws.

Slide the shredder part of the unit onto the waste bin housing until the thread of the circuit breaker sits right on top of the rim of the waste bin housing.
Mark the position of the circuit breaker and make two cuts to either side of the thread into the waste bin housing.
Once your cuts are deep enough to allow the shredder top to fully slide into the waste bin housing, use a pair of pliers to break off the excess plastic.

Carefully remove the nut of the circuit breaker. Don’t push the circuit breaker into the shredder housing.
Fully slide the shredder top into the waste bin housing, attach the marking plate and replace the nut carefully.

Replace the screws which hold the shredder top and the waste bin housing together.

Test run the shredder with the waste bin inserted.
Remove the waste bin and try again.
The shredder should not work without the waste bin.
If it does, check if the safety switch got jammed during reassembling the unit.
Fix any faults before using your shredder on a regular basis.

If everything works, you now have a Staples Mailmate with a resettable circuit breaker. No need to replace a fuse any more.

Comments

[Raider_SPE]

Man, my mailmate just failed and I was and still am pissed. This thing was a workhorse for a long time. I don't have any experience with soldering but maybe this is a good first proj?

The light still comes on but it will not get going. Would this be the fuse problem or something else?

[Mike73]

If the light still comes on, it's not the fuse. Once the fuse trips, the light doesn't come on any more.
I'd recommend checking the relays.
I've checked by enlarging one of my images, and in my unit, Staples used Tianbo relays. If you check out the picture of the PCB (the one where the 2 arrows point at the screws), the relays are the 3 black little boxes to the left. I don't know how much you know about electronics (you say you don't have experience with soldering), so I'll try to explain. The relays switch the mains power for certain functions of the shredder. One of them will most likely turn on the 120V for the unit, while I'd imagine the other 2 will turn on the motor. One for the shredding, and one to reverse the blades. The signal is given by some low voltage input. The buttons of such units usually run on 12 or 24V. The just provide the signal to the relay. Once the relay gets the signal, the relay's contact gets closed by magnetic force, providing 120V to the motor.
So if your light comes on and you know how to use a multimeter, you can press the buttons of the unit while measuring the voltage on the high voltage pins of the relays. If I didn't explain clearly enough, let me know and I'll try to walk you through. If you check the output voltage of the relays and you don't get a 120V reading (assuming you check the proper pins of the relay), the relay is stuck and has to be replaced.
BTW, I used my shredder now for a week, and it's working like new.

[Mike73]

Duh. I forgot. Whatever you do: be careful. If you work on the open unit with the power connected, it is even more dangerous. So be sure you know what you do. If you don't, don't do it. If you do it, don't do it if you're alone at home ;-)