Hi!
I have a Roomba 581 that supposedly has a water damage.
It is completely dead - no lights no anything.
I took out the battery, it is dead too. It measured 0.01V.
Can you give me some advice on how to proceed from here?
I probably need a new battery first. Or is there some way to test it without a battery and only the power supply?
When I connected the power supply directly to the Roomba, I couldn’t measure anything at the battery contacts.
When I put it onto the home base, the base LED was green permanently. But still nothing on the Roomba.
How are the 4 battery contacts supposed to work? Are 2 of them from a temperature sensor or something?
Could I maybe take a 12V battery from a motor scooter for testing? Or is the voltage too low?
I’m thankful for any advice on where to start 
Thank you Jgendron!
Yes, the home base seems to be OK. 22V from the power supply and 3V at the home base.
However if I connect the power supply directly to the Roomba, the voltage at the battery contacts is 0. This also indicates a motherboard failure, right?
I saw some signs of erosion on the motherboard, however only on few spots, not looking too bad overall.
Are there any guides on fixing the motherboard? I might try a distilled water cleaning but some reference multimeter measure values would help to rule out parts.
The roomba was not purchased from you. Any advice where I could get a new or used motherboard if the cleaning doesn’t help? I didn’t find one in your shop.
Thanks again!
I’m measuring about 20mV at the large and at the small pins.
Is the Mainboard supposed to do anything with a dead battery but the power supply connected like lighting up a red LED or something? Should the behaviour be the same no matter if connected directly or via the home base?
I just need to know that until I got a new battery…
But a 12V battery could work for testing purposes, or not?
Where could I find the motherboards you listed?
It sounds like your motherboard got damaged in this case since it seems unable to turn on the robot and unable to charge the battery. It is possible that the battery is fine but, simply is not getting charged.
Have you tested the output voltage from the robots power supply and home base? You should get 22V from the power supply and approximately 2.8V from the contacts on the robots home base. This would at least indicate to us that these accessories are working fine.
Yes, the two smaller contacts on the battery are for temperature monitoring. But, we do not recommend using any other type of battery with the Roomba.
If the power supply and home base work, we would suggest to start by replacing the robots motherboard. This usually fixes most problems after water damage. Although, after the motherboard replacement the robot could turn on but, have other damaged parts.
Was this robot purchased from RobotShop? If so, please contact us via the RobotShop support center and we’ll gladly arrange to repair your robot. Although, water damage is not covered under our 5 year warranty.
You should indeed have voltage at the robots battery contacts when the power supply is plugged in. About 5V from the two smaller contacts and a few mv on the larger contacts.
We do have guides on fixing the robot itself but, unfortunately not the motherboard. There are probably a few parts that are damaged on the motherboard in this case. We would recommend replacing it. We unfortunately do not carry any Roomba 581 motherboards considering that this robot has been discontinued.
You can also replace it with a Roomba 570 board or a 560 board if you don’t mind not having RF on the motherboard. These can be found online but, were removed from the RobotShop catalogue.
Even with a dead battery the clean light usually lights up red and you can hear the dead battery song. Although, if the battery is completely discharged, the clean button may not light up.
You can try to use an external battery for testing purposes since the motherboard already appears damaged.
Replacement motherboards can be found on ebay or other similar stores.
