Hello everyone!
I recently ran into an issue with my Roomba. We bought it used, and it came with a dead battery, so we bought a new one from Robotshop. It worked fine for about a year, and suddenly the battery charging indicator would constantly flash red. So, I did the charging reset procedure (removing the battery, holding the power button down for a minute, re-installing the battery, leave it plugged in for 72 hours.) The robot hasn’t completed the 72 hour cycle yet, but I’ve noticed the charging light is much dimmer than it used to be. It’s a solid green though. Is this normal? Or am I going to have to save my pennies for a new robot?
Thank you very much for your time!
Thanks for your reply!
I should know more of what it’s doing on sunday. I have the robot plugged directly into the charging cable so the 72 hr process won’t be interrupted. I’ve never seen the charging light so dim before, usually it’s a solid bright green when it’s charged, but at this point it’s very dim.
So, upon taking it off the charger and hitting the power button, nothing happens. 
I will post the readings as soon as I can get my hands on a multimeter. Thanks for your help so far! 
Hi again!
So, upon testing the voltages, they are all within the specs that was posted. I borrowed a fully charged battery from my friend that had a similar battery pack, and the Roomba turned on and functioned normally. I’m charging my battery on his machine in the meantime, so if it charges, then it will definitely be my mobo that is defective.
Out of curiosity, what would be the main causes of these failures?
The flashing red light usually indicates that the battery is dead and needs recharging. We suggest completing the 72 hour cycle to see what the robot does next.
Does the robot clean at all? Or will not start? If the robot cleans for a few minutes, this would indicate that the battery is not keeping charge. On the other hand, if the battery is not charging, this could be a problem with the robots motherboard or charger.
If you have a multimeter it would be a good idea to verify the output voltage of the charger, you should get 22.5VDC approximately. When the charger is connected to the home base, you should get across the base’s terminals 4.5VDC approximately.
If the readings you get are correct, and the battery is not charging, then we’d suspect the motherboard.
Thanks for confirming. Were you able to verify the output voltage of the power supply and home base? It sounds like you will need a new Roomba motherboard. We have replacement motherboards for the Roomba Discovery with a fixed black caster wheel and one for the swivel black and white type.
We also have manuals in order to help you replace the motherboard. Visit our Roomba Resource Centerfor details.
The main cause of motherboard failures are power surges. It would be a good idea to plug your Roomba charger in a surge protector.
