iRobot Roomba Discovery, Service Manual, Page: 84 / 87

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Appendix O: Roomba Engineering Changes
Gearbox Housing 2004-11-07
Change outboard housing from POM to GF NYLON which has a
higher melting temperature.
Serial Port
Housing
2004-11-15
Bevel the metal housing to reduce shorting between the hot tab of
the charging jack and the ground casing of the serial port.
Side Brush 2004-12-03 Change black bristles to white bristles which are transparent to IR
Vacuum Impeller 2004-12-12
Better balance impeller by increasing gates in mold and thereby
improve the flow of plastic.
Flapper Rod 2005-01-17
To strengthen rod and reduce bouncing internal shaft changed to
stronger steel.
Vacuum Bin
Contacts
2005-01-22
Corrosion and pitting of the vacuum bin contacts due to
contamination and vibration cause the contacts to fail. Change the
vacuum bin contacts to Nickel plated Beryllium.
Wheel Encoder
Tab
2005-02-22
Add a tab to the hub behind the encoder that seals area from external
dirt.
Ziptie 2005-04-11
Secure anti tassel halves of main brush with a ziptie. This stiffens
main brush and reduces bouncing.
IR Blocker 2005-04-11
The plastic formulation of the bumper in 41xx is transparent to IR.
Add black plastic part which is impermeable to IR.
Bearing hole 2005-04-28
Hair and dust builds up in the yellow bearing can lead to bearing
pushing out and melting and even cracking cleaning frame. Extend
axial bore through bushing for hair extrusion.
Main brush motor 2005-05-07 Change motor wire to one with higher temperature winding.
Rewiring 2005-05-09
Use less hot glue and improve wire routing on bumper, chassis and
cleaning frame
Brush Gearbox 2005-05-24
Reduce housing / output shaft clearance on main brush gear box by :
• Deepen hole in output gear to accommodate shaft an extra
1.5 mm
• Lengthen pin in gearbox tat holds output gear
• Shorten Shaft
Wheel Housing
bowed
2005-05-29
Bowed housings allow more clearance between the o-ring and
cover. This prevents the o-ring from chaffing against the cover and
allowing the o-ring dust to contaminate the wheel encoder.