Keurig K-Slim coffee maker
Symptoms:
1. Descale procedure did NOT resolve the idiot light being on for periodic descaling procedure.
2. After brew cycle the air push at the end that forces excess liquid out of the brew pod before the power off occurs not working anymore.
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| This is the business end of the K-Slim with the outer shell removed. |
I have a couple of spare old machines that were replaced under mfg warranty. Yes these machines are not very durable it seems. But the symptom above is easily corrected if you have a spare mother board available to you.
My trouble shooting involved disassembling a spare machine and testing if the air pump was able to run on test leads hooked up in right polarity from test leads from a car battery. Simply connect the + terminal to the red lead on the motor and - terminal to the black lead on the motor. I used some straight pins inserted into the modular 2 lead female plug so I could hook up my test leads... simple.
Disassembly is covered in various easily accessible YouTube videos. The secret is to remove all four small phillips head screws from the bottom of the unit before you attempt to remove the outer casing. Two of the screws are concealed by rubber plugs. It's not terribly tricky but I find you must remove the rear housing panel that faces the water reservoir before you can get enough clearance to get the main housing off. The main cover also has to be pried loose from the front facing panel piece. I am referring to where you place your coffee cup at the front of the machine when making coffee. After that, the cover comes away pretty easily.
Next I did the same thing (Case removal) to my formerly working K-Slim. In my case both air pump motors worked fine. I conclude from elementary logic that the motherboard is failed on my newer unit I am trying to fix. Another test is that you should see about 40 ohms resistance on that air pump motor.
I took several photos of the wiring attachments from various closeup angles to facilitate getting all of the fiddly little wiring leads back in the right places. You may regret if you skip this step! I had to reattach the wiring etc on my unit twice because when I checked against the photos after the first attempt I noticed I had flipped two of the big AC wires at the bottom of the mother board.
Remove all the small DC wiring modular connectors first.
There are 5 spaded connectors for AC connections. Three across the bottom of the board and two on the left edge of the board. The three AC connections at the bottom of the board are the last things to remove. All five of these female connectors have a lock tab in the center that keeps them from working loose from the male tabs on the motherboard. You must depress the tiny lock tab and apply pressure in the removal direction (away from the motherboard) at the same time (I told you it was fiddly right?).
Now remove the two AC spade connectors on the left edge of the motherboard.
Next you should pry gently on the plastic retaining hooks that hold the motherboard in place at the top. There is one on each side of the motherboard. Easily done one at a time. Now you can lift the motherboard vertically away from the base and you can tilt it forward once clear of the slots at the base of the unit.
Now look at the back side of the motherboard . You will find a neoprene hose that must be freed to disconnect it from the coffee maker. This hose end has a hard collar that works as a "hose clamp". You can easily pry back this collar and then pull the hose end off of the back of the motherboard.
The next thing is a ribbon cable that feeds the control panel on the flip up K-cup lid. It pull out vertically away from the motherboard socket. There is no lock just the insertion friction of the contacts only.
Lastly you can now flip the motherboard away from the unit so you can access those fiddly lock tabs on the last three AC connectors along the bottom of the board. This was the hardest part of the procedure for me and also where I fouled up and switched two of the connections.
Now simply (hah!) reverse all those steps and "bob's you uncle".
