How do I disconnect the quick coupler bucket on a Volvo EC150 excavator?

[George]

I recently picked up a Volvo EC150 (2002 model), and I'm trying to figure out how to disconnect the quick coupler bucket setup so I can switch attachments. The machine has the button controls in the cab, but I honestly don't know which buttons are supposed to release the coupler. I don't want to start pressing random things and mess something up. I'm mainly trying to figure out what the correct procedure for releasing the bucket?

 

[jonathan Morris]

I'd avoid pressing random switches until you identify the coupler system because some setups are aftermarket and the controls can vary.