No need to remove the fusing unit from machine.
You will need a 80mA Fuse(50mA, 63 mA it also good).
If you use a 100mA or higher value, you risk to burn the motherboard of the copier(or ICP5).
1.Shutdown the machine.
2. Open the front cover were the iu and toner cartrige are located.
3. Remove the cover as shown in the picture.
4.Cut the wires 2 and 3 as long as you can. And connect them with the fuse. You can use something like shown in the picture below(or you can solder the fuse directly).
5. Insulates connections and close all doors.
6. Start the machine, wait to warm up, check if the fusing unit is reseted and if everything is ok shutdown again, remove the fuse.
And thats all folks!