Archive for February, 2012

Fix your Keurig – again

So my Keurig decided to die again – this time it just started randomly brewing water onto the counter. The power switch didn’t work, so it got unplugged and when I plugged it back in the display just blinked “NOT READY”. It never became ready, and I was annoyed about the thought of having to shell out the cash for another one when this thing seems to break a lot anyway. So I ripped it apart to see if I could fix it. Turns out I could, and it was just a ten cent NPN transistor at fault.

Soldering in the new transistor

You have to completely tear down the machine to get to the control board. It’s actually a bit of a complicated affair considering that it’s really just a fancy water heater. The controller board is based on a PIC16F917. There are three other boards, one for the pressure sensor, one for the display, and an input power filter. The offending part in my case was on the back of the controller board. I did a little reverse engineering and figured out that the burnt transistor was an NPN, and controlled the valve that bled air pressure when the brewing cycle was finished, before the water tank is refilled. › Continue reading

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Saturday, February 18th, 2012 Electronics 6 Comments