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Showing posts from October, 2009

Repairing Roomba charging circuit

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Sometime ago, a colleague told me that she bought a Roomba 405 but the battery seems dead, unable to charge. Being the curious me and how I like to fix things, I made a deal that if I could fix it, I can use it to clean my house for 1 month :-) So, this post is a sharing and also a kind of documentation for myself on how I got the Roomba working again. Initial diagnosis.... So, the next day she brought the Roomba to me in office and I took it home. First step, I tried to charge it by connecting the AC-DC adapter to the robot. According to the user manual, it seems charging. The amber LED is blinking slowly. A few hours later, I detached the power and try to see if it moves by pressing the "Clean" button. Nope, it is dead as a log. So, next step, I took my multimeter, removed the battery and measured the battery terminal voltage. Huh, it reads approx 0.6V? Now, I gotta monitor the voltages while charging to figure out what's wrong. I attached 2 thin wires to the terminals,...