Just a quick post, but the other day, my Roomba proceeded to suck up a baby wipe (that my son had apparently left somewhere randomly and I didn’t see while picking up the main floor before bed), and the brushes jammed up enough that it didn’t trigger the “clean brush” warning, but probably overheated the Cleaning Head Module (CHM) motor (see picture). After removal, the brushes refused to run. Spinning the brushes manually was easy, so it wasn’t physically seized. Unfortunately, replacing the motor (eBay) is basically the same price as buying a whole new CHM. Checking the electrical resistance on the motor was about 8ohms. Not too bad, but, I’ve never cleaned the motor, so I gave it a few good squirts of DeoxIT, and spun it a while. Checked the resistance again, and it was 22k ohms. Huh. Hooked it up to my bench PSU at 9V, and powered it up. Nothing. Crap.
I recently found an purchased a Roomba 550 from Goodwill here in town for $32 (it was half off it’s list of $65). It came with everything originally included (virtual walls, brush cleaner, charger, dock, etc). And it was in great shape. Brought it home, and hooked it up. Initial charge, if the unit has been unpowered for more than X days, is a 16 hour battery conditioning, which is great (though it did make me a bit worried about the 2 day return policy on electronics from Goodwill).
After the 16 hour charge, I set it loose on the main floor (which is gated off from the lower floor for baby safety). And after about 30 minutes, it finished it’s run (getting probably a good 70% of the floor), and came back to dock. Awesome. With a nightly run, it’s bound to get “everything” at least once a week. So, I set it to run every night at 1AM, and went to bed.