The very latest news and updates for the iRobot Roomba robotic vacuum, the Scooba Robotic Washer and the Dirt Dog workshop sweeper. All discussion and troubleshooting questions go here.
Although no-one has actually experienced a true hardware failure of the H-Bridge NPN/PNP bi-polar transistors used for the drive wheels on the 500, 600, and 700 Roombas, a little preventative mini mod can be done to improve the odds of never having the issue. Using a pair of cutters, one can form a set of heat sinks from something like a blank aluminum name plate. Just cut it into quarters then apply a dab of thermally conductive silicone adhesive and mount each strip to the back side of each transistor. The adhesive sets up hard in 24 hours.
- Robot Master
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- Joined: January 14th, 2006, 8:31 pm
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Just a little side note, vic. As of the very next day (21st) we can no longer make this claim:
vic7767 wrote:Although no-one has actually experienced a true hardware failure of the H-Bridge NPN/PNP bi-polar transistors used for the drive wheels on the 500, 600, and 700 Roombas, ...
Member matofill reported in this post
replacing two power xstrs in his R3-Roomba that effected operational repair. Communication with matofill brought forth data that strongly suggests his transistors failed due to some cause other than over-heating.
- Robot Master
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- Joined: April 6th, 2005, 2:02 am
- Location: Santa Ynez, CA USA
The other cause may be water damage as the H-Bridges are not covered by the plastic under the keypad.
I had repaired a 540 with one of the wheel running all the time with transistors failed shorted.
- Robot Addict
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