Ot: Need Help With Dead Roomba


Hi all,

This is off topic but I know there are a few people here that may be able to help. Please forgive.

I've got a Roomba model 531 and it's stopped working. Completely dead and unresponsive. No light around the start button when it's docked on the charger or when it's pushed to start it cleaning. The charger led light turns on green when the Roomba is placed on it.

I thought it was a bad battery so I bought and installed a new one and still the little guy won't wake up.

Any ideas or am I SOL.


The symptoms do sound like a bad battery. Have you tested the battery voltage?


The old battery I removed tests at 12vdc. The new battery tests the same. Frown


I do know the rooms must charge at least 24 hours when a new battery is installed before it will go through a normal run cycle. If a battery is removed or goes too dead ( low voltage) the battery monitor resets and requires to be on the charger all day agian..


12 volts sounds like a dead battery bro. Roomba batteries start at 14.4 volts and go up to 17 volts when charged.


Humm, I'll leave the new battery on the charger overnight and see what happens.


Try plugging the charger directly into the side of Roomba.
Attached is a response of a similar problem. It said there is charging circuit safety that some times burns out.
Robot-Doc can tell more.

Help link


Ah yes the famous 1 ohm surface mount resistor (R138) that fires up the 5 volt power to the Roomba MCU. A quick test is to measure the resistance value of that resistor. If it is more than 1 ohm you can short it out and then see if the Roomba will go into charging mode. If so then replace R138.


Thanks all. Looks like I'm going to have to dig into the little guy a little deeper. I'll keep you posted. Winky


Well, I took the Roomba all apart looking for the circuit board and tested R138. I get 1.2 ohms so it looks good. Just for kicks I jumped this resistor with the charger plugged into the side of the Roomba. Nothing, still dead.

I have all the wheel and brush units pulled out. Does this matter? Do they have to be installed for the charging pulse to start?

Any other ideas? if not is there any place that repairs these little guys or is it even worth it?