We used to have Krupp’s Coffee maker which worked great for many years, but at some point the coffee pot cracked. Unfortunately, it was not possible to buy just the pot. Although the coffee maker was working fine, we had to recycle it. Before recycling it, I took out the heating element thinking that it might be useful some day.
Last Christmas we got Mr Coffee coffee maker because you could buy the coffee pot separately if it cracked. It worked fine until last week July 22nd, 2012, then stopped brewing. After pressing the Start button, the lights would come on, and you could hear a ‘click’, but then it would not brew.
When I wanted to open it up, six Phillips screws underneath it came out without any problems. However, there was also a locking Torque screw which was impossible to open. We checked on the warranty and it turns out the unit was still under warranty. When I called the local office about it, they simply did not want to deal with it and I don’t blame them. It is just easier to buy another one.
But in my case it is more of a challenge to see if it is possible to fix Mr Coffee. I drilled through the locking Torque screw to find out why it was not brewing.
Voiding the warranty.
Here is how the underneath of the MrCoffee looked like.
Power Connection 1
The black cable marked “in” with the yellow arrow in the picture above shows the power coming in from the wall plug. There are three connections: the first one (marked “1″) is the neutral, the second one marked as “2″ is the hot side. Through the relay, the power travels to the third connection marked as “3″.
Here is a better view.
Power Connection 2
The heating element terminals are shown with red arrows “1″ and “2″. One side of the heating element (red “1″) is permanently connected to the neutral line with the white wire. The hot side (“1″) after passing through a relay (“2″) is connected to point “3″, then “4″, and “5″, and to the other side of the heating element. When I measured the hot side voltage, the current was flowing all the way to “5″, but there was no voltage at the other end of the heating element (red “2″). This meant that the “diode looking” part connected from yellow “5″ to red “2″ was defective.
Here is a better view of the relevant parts.
I cut these two parts out and tried to read the markings on them. “MICROTEMP G4A01 TF216C” was stamped on both. It turns out they were thermal fuses to protect the heating element. If you think about it for a minute, you can see that at any one time only one of them would break the circuit, which meant that the other one was spare.
I soldered the parts back in and short circuited the defective one (the one on the right). And that was it! MrCoffee has been brewing fine now without any problems.