iRobot Scooba 390 Repair

On page 50 of the attached Service Manual, the result of a Built in Test (BiT) can be captured to a computer. You will need a special cable to do so. Do NOT buy this cable as it has an L-shaped end that plugs into the Scooba's communications port, but the cable wire will need to point down and bend sharply so it will not work for a 300 series Scooba. You really need to find an IROBOT 4814 Roomba Create Serial Adapter, and then an ordinary USB to Serial converter if your computer does not have a 9 pin D serial port. HyperTerminal is still available for a price but TeraTerm will work also.

The BiT can be run while connected to a computer, but you will not be able to do the tank tests as the tank covers the communications port of the Scooba. You will be able to understand what is going on during the BiT and you will be able to see the results of the BiT in real time.

I have worked on 16 of these 300 series Scoobas and I am finding that parts are swappable among all of these models. For instance, I was able to get a Model 390 running by taking the User Interface from a Model 5800 and plugging it into the 390. If you are trying to get a 390 going, any 300 series Scooba will work for parts.

The only other gotcha that I want to add is some of the early 300 series Scoobas have a bug concerning the internal battery charging. It is best to fully charge the battery (3 to 4 hours) and then remove the battery from the Scooba for storage. Batteries are available from here.