Instructables

Roomba 400 Series Disassembly and U2/U4 Charging Fix

Picture of Roomba 400 Series Disassembly and U2/U4 Charging Fix

Is your Roomba 400 not charging? When you plug it in, does it light up but when you press the button you get no response? Here's the disassembly guide as well as a guide to fixing the U2/U4 Problem. This will also give you a chance to clean out all the Dust that builds up inside, you could clean out the inside of the brushdeck and preform the sealed bearings mod, and much more. In addition, once you open it up, you can see and clean all of the dust balls inside. Literally, the inside is usually PACKED with dust. That dust is harmful to the Roombas in many ways.

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Step 1: Intro to Disassembly

Picture of Intro to Disassembly
All Bumper and Cover retaining screws must be removed before attempting dismount of either subassembly. The two subassemblies must mechanically disengage Chassis fittings as a set; at least for the first few millimeters of movement. Steps in HoB apply to the following Discovery models, in which the Handle is mounted on the Bumper and interleaves with the Cover: Roomba-Discovery, #4210Roomba-Discovery Replacement, #4211 Roomba-Discovery SE, #4220Roomba-Scheduler, #4230 Note: We have not had hands-on experience with the Discovery SE, or Scheduler models, but those bots are considered mechanically identical to the #4210 Discovery, which is known to reward owners when the HoB process is used. Models #4210 and #4220 that were produced prior to, roughly, mid-2005, came with some removable parts that are called "Fender Skirts" in these documents. It can be useful for an owner to recognize whether his Roomba has Fender Skirts, because their presence provides much easier access to the drive-wheels; and also explains why two very long screws are used just forward of the drive- wheels. The image below has pointers to the joint features which indicate presence of a Skirt. A Fender-Skirt is a removable panel which spans the distance between those joints. Roomba-owners who purchased either of these Discovery models after mid-2005 should inspect the left and right sides of their bot to see if "Fender Skirts" exist on their particular unit. If no Skirt-joints are visible, no Skirts exist on that Roomba.
guywire1 year ago
What's going on between step 8 and step 9? After step 8 there's still about 30 connections of wires, springs, mounts, etc to the main board.
I have a roomba 400 that the beater bar/brush assembly runs constantly. Pressing the CLEAN buttonturns the unit on and it goes through the cleaning motions but depressing it again to turn the unit off turns off everything except the beater bar/brush assembly. Suspect a shorted driver chip or transistor. Are there schematics available for these older model Roombas and if so where? Thank you.
robotmaker2 years ago
great video for others having problems with charging circuit
i use Gordons schematic alot for repairs and upgrades
i have alot of roomba's for different robot designs i am testing
like TURTLEBOT using ROS software,and SERVERBOT design and yours
i like it better then my IROBOT CREATE,its low cost,plenty of room once you remove the vacuum parts and can handle up to 35 lb carring load