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Released in 2012, Identified by Model Number: R630020

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What is the voltage DC out of the charger? I am getting 2 volts DC.

I am getting 2 volts DC out of the terminals in the charger for a roomba robot 621. It is that correct? What should it be? Thanks

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I am getting also 2 DC Volts between docking terminals. The battery charges properly with a DC 21V power supply directly connected to the robot.

Any docking repair guide available?



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add some images showing us where you are measuring. The DC output on your power supply should be between 21V and 24V. Your battery voltage should be between 15.5V and 18V. This could be an issue with the power supply.

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I have just been working on a base station.

The power supply PCB inside these is not a normal, constant voltage power supply. It is a constant current supply. It supplies 1.2A at up to 22 volts. If you use a power supply that supplies more than 1.2 amps, the Roomba will stop charging with charging error 2. The roomba does measure the charge current and stops charging with that error if it is too high.

As for the voltage across the terminals - I would expect that it puts 2 volts across it to detect the vacuum. Once it detects it, it then provides the voltage to charge the battery.

I have been unable to locate a replacement power supply PCB for the base station, but there are power adapters used in more modern ones, but I don't know if they would work if wired in. I have ordered a replacement dock - running it off an adjustable step down adapter is a bit messy.

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Thank you. This is an extremely helpful answer. My machine is a 700 (or 7xx if not(. Across the inner and outer contacts of the barrel connector of the charger, I see 22V. When plugged in, across the spring terminals of the docking station, I see 2V. The beacon on the docking station is working and the Roomba approaches and tries to mount the dock, but then baulks and wanders off to the right. I thought it might be the bumper, so I dismantled, cleaned, and refitted it. No improvement. Even if I place the Roomba directly on the docking station, it does not respond. I am able to charge by plugging the Roomba in directly via the barrel connector, but I want to use the docking station for automatic cleaning and recharge (as it used to do).

I don't know whether the docking station is failing to detect the Roomba and begin charging at higher voltage or whether the Roomba itself is failing to detect the docking station and begin charging.

I have cleaned contacts on both the Roombav and docking station.


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Jaime Sanchez Tobon will be eternally grateful.
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