Single Serve Coffee Forums

Mod note: See links to potentially useful files and diagrams at the bottom of this first post

Before I get into the how-to part, I'd like to explain a bit of background about this coffee machine and it's problem.
I purchased the unit as-is on ebay with the intention of fixing it, however I found it too difficult and time consuming to take apart and set it aside in favor of repairing other things. Just about a week ago, I dug it out of my basement, and got to work on it.

The Problem The machine will take water from the basin, the valves work, but it does not brew a full cup of coffee. This seems to be a common failure with this unit.

The Cause Water is being fed into the air pump located at the bottom of the unit causing it to rust and seize. In this tutorial, I will explain how to disassemble your machine and fix this issue.

On to the disassembly...

Disassembly

You will need to flip your unit on its side for the repair procedure. Lay cloths or paper towels underneath the unit, as it will leak from the K-CUP arm.

• Remove the bottom plate. There are a few Philips screws holding the metal plate on. The grounding wires are riveted onto the metal plate, preventing complete removal of the plate.
• You are now ready to remove the plastic frame. Locate the screws for this frame around the bottom edge of the unit. There is another screw by the drip tray, and another by the basin pump. Do not pull the frame yet.
• The basin pump and basin LEDs must be removed now. Locate the 1 screw for the LED and the 2 screws for the mouth of the basin pump. These are located directly below the basin.
• Pull the frame out and de-route the power cable (optional). Be careful of the basin pump, you will need to bend the tube connecting it to the pump. You may want to unscrew the pump.
• Remove the 2 screws from the underside of the K-CUP arm. Open the K-CUP arm. Remove the holder.
• Remove the 2 black screws located in front of the holder (inside bottom). The body piece will fall off, hold it up with your hand when unscrewing then pull it off.
• Look directly above of those 2 black screws, you should see two more screws on the top of the K-CUP arm. Remove those screws and slide the body piece out from underneath the handle.
• Remove the 2 screws securing the top cover to the frame of the unit. These are higher than the K-CUP arm's two screws. You only need to remove the top cover's two screws. Pull the top cover up from the gap, this will not remove it but it will loosen the clips for removal.
• Flip the unit on its side again.
• Get a flash light and look in the cavity where the water basin was, locate the clip securing the top cover of the unit to the case. It is located directly back of where you are looking, it is not on the side wall of the unit. Pry it back towards the back of the unit and push up. This requires a lot of force, you may want to use a long screwdriver or tiny crowbar.
• Stand the unit up again.
• While the unit is still on its side, pull up the top cover a bit more. Shine a flash light into the gap and locate another clip on the back side of the unit. Use a screwdriver to push and pry upwards on the clip. It should come loose. Do this for the next few clips as the come loose. Pull off the top cover.
• Unscrew the two screws above the LCD. Unscrew the screw securing the back cover to the front panel on the other side of the unit. Slide the back cover down and pull it back to remove.
• Your brewer is now fully disassembled. If i missed a step, please correct me, but i think everything is correct.

Repair

You can now replace the 2 valves in the unit, repair any leaks, repair electrical connections (the power board is located on the LCD side of the unit near the bottom in a black box.), repair non-functional pumps, and re-prime your brewer.

However, I will go over how I repaired the problem with the brewer not pumping water.

The pump is located at the bottom of the unit, on the side opposite of the LCD. Remove the pump by unscrewing the unit and desoldering the connections (underneath black heatshrink tubes). Make note of the polarity before removing.
Remove the tube from the pump, if there is water in it you will need to drain the tube and then flush the unit's tubing. We will do this after re-installing the the pump.
Pull the tube out, and remove the three black screws from the pump. Remove the white plastic cover. You do not need to remove anything else on the pump.
Rinse your tube under a faucet, making sure to get water into the holes on top of the pump. Shake the pump vigorously to remove the residue causing the motor to seize.
Test the pump by plugging it into a 12V power supply. I cut an old phone power supply and attached the wires to the leads of the motor. Polarity does not matter while testing.
Repeat the rinse and shake process if the motor sounds like it is slowing down every so often. It should be running quickly at a constant speed.
Once it passes testing, dip the pump in cleaning alcohol then shake out the excess. This will speed up the drying process. You may want to wait a while before reinstalling, but it usually does not matter since cleaning alcohol will not conduct electricity.
Resolder the wires, use heatshrink tubing or electrical tape around the connections. Reinstall the pump into the unit and attach the tube, using a zip-tie to secure it. You may want to re-prime your machine before preforming a test brew.

Re-Priming

Remove the tube running from the water reservoir to the K-CUP arm unplug it from the percolator only, leave it attached to the reservoir.
Remove the large tube that runs from the underside of the reservoir (the bottom is metal), unplug it from the black tube splitter only! Do not unplug it from the bottom, unless of course you'd like to spend the rest of the day mopping up water. This is where the water will come out when we empty the reservoir, place a cup at the end of the tube so it will drain into it.
Blow air through the tube that lead to the K-CUP arm. I just used my mouth, but if you're a clean-freak you may want to complicate the process by using a pump.
Once the reservoir is empty, plug the tubes back in. You do not need to use a zip-tie until reassembly.
Flip the unit on its side and reinstall the frame. Reroute and screw in the water basin pump mouth. Flip the unit back over and install the water basin.

Entering prime mode
With an empty reservoir, turn the machine on and wait for it to say "Ready to brew"
Press brew and wait 60 seconds. Attempt to turn the machine off with the switch. If it does not turn off, you are now able to enter prime mode. If it turns off, repeat the first step and wait longer.
Unplug your machine, keep the cord near the power socket and hold it with one hand. Press Left + Menu + Right and plug the machine in. The LCD should stay off, or flash blue and then turn off. Press brew in addition to the other keys. Keep holding these down for the next step.
Reach around the unit with your hand still on the buttons and press the on/off switch on the back of the unit. The unit should automatically start filling the reservoir and then start brewing a cup of coffee. If it does not start, press brew immediately after the screen comes on.

Perform a test brew and reassemble the unit.

Congratulations, you've fixed your pump and successfully repaired your keurig B70!

--------------------

More pointers for the mechanically inclined:

- EmmJayEff's theory of operation and tube routing diagram [.pdf, updated 7/21/12]
- Jay Aitchsee's simplified operational diagram
- EmmJayEff's schematic and parts list for the solenoid/air pump/water pump driver circuits on the KE779L7 power board [.pdf, updated 9/29/11]

Now that's what I call an epic first post! Welcome, and thanks. Out of pure greediness, could I ask if you might have a few pics?

p.s. I understand more clearly now why Keurig just replaces these rather than repairing them...

jbviau wrote:Now that's what I call an epic first post! Welcome, and thanks. Out of pure greediness, could I ask if you might have a few pics?

p.s. I understand more clearly now why Keurig just replaces these rather than repairing them...

I have pics of the pump and the tubes, but that's it since I didn't think to take pics when I was working on it. It's actually surprisingly easy to disassemble once you get the top cover off.
I only paid $15 for the coffee maker, and I got all of the accessories so I'd say that even with all the effort it's still worth it. I'm actually thinking of buying more of these to sell.

switch998 wrote:

jbviau wrote: I'm actually thinking of buying more of these to sell.

Love the way you think

Whoops, I noticed a problem with my post that I didn't catch earlier.

Pull the tube out, and remove the three black screws from the pump. Remove the white plastic cover. You do not need to remove anything else on the pump.
Rinse your tube under a faucet, making sure to get water into the holes on top of the pump. Shake the pump vigorously to remove the residue causing the motor to seize.

replace "tube" with "pump"

And here are the pics from my phone.

View from top of unit: http://i923.photobucket.com/albums/ad72 ... 001940.jpg
Pump with basin during reprime http://i923.photobucket.com/albums/ad72 ... 01515a.jpg
Closeup of pump: http://i923.photobucket.com/albums/ad72 ... 001515.jpg

How timely!

The problem with mine was indeed that the motor was a bit jammed. I got to the point in your procedure where I was supposed to be using a flashlight to somehow get the upper cover off. I did remove the two screws for the upper cover, but didn't get further than that.

Fortunately, with a little bit of prying and sliding a screw driver between panel pieces, I got the side panel up a bit, enough to access the screw that holds the motor in. I really wasn't in the mood for desoldering either, but I dismounted the motor removed the pump piece and twisted the white piece with the hole on the end of the motor shaft. At first, it turned hard but then it turned easier. That seemed very encouraging. So, to put in a slight more effort, I undid two screws that hold the bracket piece to the motor. I discovered an additional hole into the motor, though which I could sometimes see the windings as I slowly turned the motor. I took a small screw driver and gently poked in and out of that hole to try to remove or dislodge dirt. Then I'd turn the shaft past the next winding and try to clean with the screwdriver again. At the end, I could give the motor a twist and it would continue to spin for a revolution or so.

Then, it was time to reassemble things and, as often is the case with me, I had a few screws left over at the end. Getting the bottom plate in place was a little tough and so was getting the arm cover on in the right position.

Since the machine had claimed it needed descaling, I had most recently had vinegar in the system. I didn't see any signs of dirt or obstructions in the tubing and I was really hoping I wouldn't have to prime the pump with water in some way.

When I put it back together, it was now happy to pump the vinegar through the system for the descaling process. Then I pumped through a tank of water, a cup at a time, as they suggested in their descaling process. Then I made a cup of coffee. The color looked great, but yecch! As they said, sometimes it takes more than one tank of water to get rid of the vinegar flavor. However, each cup seems to be a consistent volume. (It wasn't before.) So after another rinse or two, I hope to have my morning coffee at 2PM in the afternoon.

Thanks,
Bruce

Open question for the tinkerers: Could the machine be upgraded with more reliable parts? It's great that you can do repairs, but what about a more permanent fix?

You need a 12V 4 PSI pump air pump with the tube hole at the bottom, the diameter is 1/2" i think. The KPM27C is a compatible pump, since the machine (at least mine) doesn't run the pump at 12V, you can get specs for the 6V version of the pump here: http://www.clarksol.com/html/prodspecsKPMRPump.cfm

The problem is that the water will run back down the tube and rust the pump, so I think a one way valve could be used on the tube to prevent this from happening.

Perhaps you could buy broken machines for next to nothing if they are cosmetically damaged. Strip for parts and sell as repair parts with your directions. It could be a huge markup just like any parts business,
Mary

If you have two units, is it possible to replace the control panel without completely tearing this apart? Has anyone even tried taking one of these control panels out of a B70? I have a broken machine (pump issue) that's pristine and one that works great but the control panel is cosmetically damaged.

TIA

I have my malfunctioning Keurig apart while the new one that Keurig gave me makes my coffee. Is there anywhere an explanation of how this machine functions ? There are lots of parts but on mine no obvious defects. I am a retired EE with lots of time and curiosity. I have looked up Keurig for Patents and see some cited ones of interest, but it would be nice to see a simple explanation of what all these parts do.

donb

OK: I have found a basic description of how the parts of the Keurig machine work together. The patent listing on the bottom of the carton lists a few that include a general system description.

From what I can see, my symptoms were consistent with a malfunctioning air pump. I will tackle that first.

donb

Yup: The air pump would not rotate with voltage applied. Would not rotate after I took it out and apart. Reason is the shaft and bearing are heavily corroded. There was some water in the pump section next to the motor bearing - obviously not designed for a wet environment. The pump diaphragm looked intact at a quick glance.

List price on pumps at Clark solutions is $15. The little motor looks like a 50 cent item, if I knew where from.

Don b

Hi, I read this post and it was very helpful in assisting me when I took apart my B70. Turned out the 12 volt valve at the very top of the unit. I called Keurig today to see if they would send me a replacement part and they said no. They did replace the entire unit though! The Keurig was purchased in 12/2009 and I never registered it. They took down a lot information but then came back and said they were shipping a new unit and to return the K-cup portion of the machine. If anyone can use a part I won't mind sending to you.
Thanks again for sharing information,
Brian

Welcome, Brian! Glad to hear it.