5. This is the complete CHM – “Cleaning Head Module”.
Arrow points to the gearbox side

7. This is the mating area where bristle brush and beater brush meet the gearbox.
The gap between the gear wheel cylinder to the plastic housing is the area which this mod is dealing with.

8. Take apart the CHM module by first unscrewing 1x PCB screw and releasing the motor tension cable. See next images.

9. Take off the small round sticker that keeps the motor tension cable head.
Grab the head of the tension cable with a small pliers/tweezers, pull it up and
slide it through the cable slot to release it.

10. Disassemble the PCB by first unscrewing its single screw.
Next, release the cables from its hook
Now push the PCB down to release it from its slot.

11. Separate the Gray CHM module from the Blue external frame by first spreading its ‘wings’ (one after the other) and by rotating the CHM inner Gray case.
Be careful not to use excessive force.
 Though the image shows the module prior of PCB/tension cable disassembly, you should perform this step AFTER you disassemble the above PCB/tension cable.

12. You now have access to the motor.
Unscrew the 2x screws of the motor bracket that holds the motor.

13. Pull the motor aside and temporary secure it with a tape.

14. Remove the gearbox sub-assembly by unscrewing its 4x screws.
Pay attention that one screw is shorter! This is important when you’ll assemble it later on.

15. Pull the gearbox and separate it from the module.
Unscrew the 2x screws holding the gearbox cover plate and open it.

16. This shows the open gearbox with all its wheels assembled.

17. 3x wheels needs to be modified by adding bearings to the wheels.
The gearbox wheels openings of those 3x wheels needs to be expanded to fit the bearings .

18. Now contract the gear wheels cylinder diameter.
Modified diameter should meet the inner diameter of the relative bearing. Mating should be tight.

 Motor wheel needs to be contracted and on both beater and bristle wheels we need to first remove its external ring wall and then contract its diameter to meet the bearings

19. Diameter contraction is done here with the help of an electric screwdriver and a file.
First image shows the motor gear wheel which is held with a 4-40 screw
Second image shows the ring wall removal with an arc saw
Third image show drilling the bristle wheel in order to allow restrain it to the drill.

If possible, prefer using table drill or a lathe for perfect centering and alignment
Pay close attention not to file too much !
Check fitting to the bearing often till you reach needed diameter.
 Don’t file the gear, just its mating cylinder diameter !
Make sure that file’s flat surface is pointing towards the gear.

• Motor wheel cylinder size fits bearing inner diameter of 6.0mm. Stop modifying at 6.3mm
• Beater wheel cylinder size fits bearing inner diameter of 10.0mm. Stop modifying at 10.3mm
• Bristle wheel cylinder size fits bearing inner diameter of 15.0mm. Stop modifying at 15.3mm

• Hole size for motor wheel fits bearing outer diameter of 10.0mm. Stop modifying at 9.7mm
• Hole size for beater wheel fits bearing outer diameter of 15.0mm. Stop modifying at 14.7mm
• Hole size for bristle wheel fits bearing outer diameter of 21.0mm. Stop modifying at 20.7mm

21. When reaching needed diameter, insert the bearing with a little force.
Lubricate the gear wheels using Lithium grease, assemble the gear wheels and gearbox cover.

Here you can see the gearbox with the bearings installed.
If using a flanged bearing, the flange should be on the gearbox side.

22. Assemble the gearbox to the housing.
Slide the motor to its place and pay attention that its rod hex shape will mate with the gearbox wheel. Also pay attention to the motor position in the gray housing.

23. This is the assembled module from inside.

24. Test CHM. You can use a 9V battery or a power supply if you have one.
Connect + to the Red motor wire and – to the Black motor wire. At 15-16VDC, current should be less than 0.5A
If you test it without the outer frame, hold the tension wire to allow it to work.

25. Assemble the CHM outer Blue frame.
Start with the PCB and pay attention to its direction in the slot of the outer Blue frame.

26. Return the tension wire round head to its place.
Attach the old / new small sticker to cover the tension wire head recess / slot.