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Dissassembly + Repair Guide - Keurig B70 Platinum

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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby hotwasabipeas » Fri Sep 16, 2011 3:06 pm

I just got done cleaning both needles and I ran water through but there weren't any coffee grounds visible in thw water so I don't know if that was the problem. I will have to wait until tomorrow morning as that's when the problem starts, with the first cup I try brewing for the day.

Could any of this be related to using the My K-Cup? This week I used the My K-Cup and it took at least twice as long to brew a 6oz. cup. I ground the coffee fresh and at a setting I thought should be the right coarseness but it must have still been a bit too fine as the water took longer to go through compared to a regular K-Cup. I didn't mind as I thought the coffee tasted great even though it took longer. Could using too fine a grind put strain on the B70?
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby jbviau » Fri Sep 16, 2011 3:09 pm

hotwasabipeas wrote:Could using too fine a grind put strain on the B70?

I suspect so without having any real concrete proof. Anecdotally, brewing using too fine of a grind in my Solofill was followed pretty soon thereafter by the death of my last B40. Correlation doesn't equal causation and all that, but it made me wonder.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby hotwasabipeas » Fri Sep 16, 2011 3:40 pm

Guess it's time to call Keurig. I just tried to brew using a My K-Cup (I used an even coarser grind than before) and it didn't brew. I had only used less than 2 hours earlier and it worked then. The water was being drawn out of the reservoir and, even though the display said "Brewing", no water was coming out. So I tried again by opening and closing the lid and then pressing brew. Once again water was being drawn out of the reservoir but, alas, no coffee! So I powered down, tried again...same thing. Powered off yet again and tried and this time it brewed but this was also the first time I ever saw water re-enter the reservoir from near the top where the lid sits. I never knew there was an opening there for water. This is frustrating as I knew that these machines could be problematic but I took precautions by using the water filters and also descaling twice now even though the B70 is only less than 3 months old.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby jms » Sun Sep 18, 2011 8:25 am

i am also having the same problem..i disassembled the unit removed the "motor" at least i think it was the motor..spun the wheel around and it moved easily.. blew out the tubes had no water in the unit.
reasembled but the only thing i did was fill the reservoir and try to rebrew..

should i repeat the whole process and blow the tubes out again and then do the restart with an empty resevoir as the directions say on the first post of this thread??

they are sending me a new maker after they tried to help me.. i got 2 cups of 8oz water but then it stopped and she said she would send me a new unit....sigh
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby jbviau » Sun Sep 18, 2011 9:36 am

^^^ Welcome! Glad to hear you have a replacement coming.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby Bosco390 » Tue Sep 20, 2011 4:14 pm

hotwasabipeas wrote:Anyone have any idea what's wrong with my B70? For the past 3 days I am often having problems getting it to brew. The display will say "Brewing" but nothing comes out. I can eventually get it to brew after turning it off and on a few times. After it finally brews it works fine for the next few cups. The problem resumes again the next morning when I first try to brew a cup. The B70 was purchased brand new this past July and I have always used their water filters in the reservoir. I did descale it yesterday using Dezcal, which is what I use for my Starbucks Barista espresso machine.


In my rather limited experience with my "rehabilitated" B70 at work (I replaced the air pump and put umbrellas over the transformer and the air pump), I have occasionally experienced this same symptom... first cup in the a.m. if quirky, but then all seems ok. Mine was a sticky solenoid. I would be interested in knowing if, while it says "Brewing" but it's not brewing, are you seeing flow out of the overflow tube back into the tank? Glad you have a new one on the way! Way to go.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby hotwasabipeas » Wed Sep 21, 2011 11:21 am

Actually I got mine to work again and it's been fine for the past few days. I did call Keurig and they had me go through all the troubleshooting such as cleaning the needles, blah blah blah. I did all of that even before calling them and the rep wanted me to run through some vinegar and let it sit in the brewer for 4 hours. I told him I had just used Dezcal in it 2 days prior but it didn't matter to the rep. He wanted me to try the vinegar and if the Keurig still had problems after that then they would send me a new unit. After I got off the phone with them I decided to do my own troubleshooting and here's what worked for me. I ran some cleansing brews and while it was brewing I very firmly slapped the top of the Keurig from right above the K-Cup holder area all the way to the rear of the top area. I did that maybe 4 or 5 times in a row and I did notice, at least the first 2 or 3 times when doing this, that there were quite a bit of coffee grounds in the water. More than I had ever seen before, even when cleaning it with Dezcal. When there were no longer any visible grounds in the water I stopped. It's been brewing great ever since. Maybe some coffee grounds had become impacted and even Dezcal couldn't dislodge them? At least it works now and hopefully I won't have this problem again....fingers crossed!
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby hotwasabipeas » Wed Sep 21, 2011 11:37 am

Bosco390 wrote:I would be interested in knowing if, while it says "Brewing" but it's not brewing, are you seeing flow out of the overflow tube back into the tank?


Yes I did notice water coming out of the overflow tube back into the reservoir but only once. Usually I would open the K-Cup holder lid and close it again to see if I could get it to brew. Each time I did that more water was leaving the reservoir but it still would not brew. Eventually when I did get it to brew, the cup would overflow. Only one time did I see water flow back into the reservoir from the overflow tube.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby Dan4111 » Wed Sep 21, 2011 8:17 pm

I may have found a permanent solution to the leaking solenoid problem (which is the number one cause for the air-pump to seize up). The solenoid that leaks is the FWD solenoid, which after studying emmjayeff's tube diagram and one of my bad units, appears to be totally unnecessary. Before I explain, I should focus on the water pump and how it works. There are 3 ports. One large port (inlet from basin), one medium port (outlet to water heater), and one small port (pump flow-control hose). The basin water pump is controlled via duty cycle, which means the computer can control the speed of the pump motor itself. This small tube from the pump must be able to draw a vacuum while pumping, or the water will not be pumped. If you were to apply pressure to the small hose, the pump flow would decrease. If you were to apply vacuum to it, flow would increase. Neither one of these condtions will ever exist on this machine since the small hose is tee'd into the reservoir overflow/vent hose (ambient pressure). Looking at the tube diagram, you'll notice that the FWD solenoid is pretty much just there to tie pump output to the flow-control tube, which would cause low pump flow if the solenoid was commanded ON (open) during water heater filling, but its not, its commanded OFF (closed).

So I removed the solenoid (which was pouring water out anyway), and replaced it with a automotive vacuum check valve, flow towards pump output, to keep pump output water from pushing back into the vent circuit. So far it has worked flawlessly, and not a drop of water shed.

Summary: The FWD solenoid appears to have no function, other than to leak all over the place, and *maybe* to provide pressure relief in the tube from pump to heater (which I do not believe is necessary). Also, this solenoid is rarely turned ON (open), I believe only for the topping off stage, which really has nothing to do with this function. Another nice note is that the AFT solenoid appears to never get water flowing thru it like our troublemaker FWD solenoid, meaning that the AFT solenoid (MVP in this game) should last for a much longer time.

A note: The AFT solenoid is absolutely required. Without a properly functioning AFT solenoid, the machine will work for a few times, but that's it, because the topping off stage will not occur, so when the heater is low, that's it.


Sooo, this is starting to look like planned obsolescence at its finest. Running water thru a vacuum solenoid which has an "acceptable leak rate" in its specs, which appears to have no true function, and its placed directly above the air pump motor. Hmmmmmm......


So who wants to try this out and help me confirm this fix?
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby Dan4111 » Wed Sep 21, 2011 8:24 pm

Oh, forgot to mention, for anyone who might have been curious, the 5 cup-size brewer (select?), that I was working on in my first post, ended up being a bad mainboard. Shame, that was a nice machine. Anyone got a board they wanna sell?
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby Dan4111 » Fri Sep 23, 2011 10:22 pm

o I've recently taken these things on as a hobby, lol. Always loved a good challenge, and these are good for that. So anyway, I like to snap phone pics of a project sometimes, and this time I decided to put them to use. So.... Welcome to class.





Air pump motor repair 101:

1.) Loosen the 3 PH00 screws and remove the pump as an assembly.

2.) Remove the 2 PH1 screws that hold the pump housing in place. Remove the pump housing and metal bracket plate. Pull the plastic eccentric hub off the motor shaft Now you have a bare motor.

3.) Bend the 4 crimps outwards. You can then gently tap the motor shaft on a hard surface until the back cover of the motor pops out. If it doesn't pop out easily you probably have a crimp or two that need to be bent out further. NEVER pull on the terminals, you will ruin the brushes. It is advisable to attempt to remove the armature with the brush holder (back cover) as an assembly. If you can't, its ok, but the white plastic thrust washer will need to pull past the brushes since its stuck on the shaft, so be VERY gentle, the brushes bend easily (and *do not* bend back easily).

Image

4.) Gently remove the armature from the back cover, and remove the white plastic thrust washer. You can then clean up the armature and commutator with some fine (like 320 or so) sandpaper. Do not put the white plastic thrust washer back on the shaft just yet.

5.). Now you need to make a tiny round-file. I used an 1/3 unbent paperclip, and roughed up the long end with a dremel tool cutting wheel. Use this "roughed-up paperclip" to file the rust out of the front bushing, and blow clean. Clean any rust off the magnet inside the field casing. I like to apply a thin film of oil (I've been using 3-in-1) to the armature, commutator, and magnet. Make sure to oil the bushing you've just cleaned too, and run the long end of the shaft in/out and spin it in the bushing to distribute the oil.

Image

6.) Gently close up the brush gap to allow almost no space between the brushes, this allows the brushes to hug the commutator tighter. Drop some oil into the back bushing (inside the rear cover/brush holder). Use the oil to stick the white plastic thrust washer over top the bushing hole, behind the brushes.

Image

7.) Now gently use the armature shaft to push and wiggle the brushes out of the way (again, *gently*!)to get the commutator past them, and slide the shaft thru the thrust washer, into the bushing. Now you have the armature/back cover as an assembly again.

Image

8.) Now its time to slide this assembly into the field casing. Make sure to line up the keyway first. The insertion must be done in one smooth movement, as to prevent the magnet from "sucking" the armature into the casing, and pulling it back out of the brushes. If this happens, you must repeat the latter half of step 6 and all of step 7. I try to cock the armature in the housing and "scrape" it into place, then this way it has friction as it rubs down into place.

9.) There is a little step shelf inside the back of the casing that prevents the cover from going in too far, so once its in place I use the tip of my PH1 screwdriver to tap the cover down. Now you can re-crimp the 4 points and test 'er out.

Image

You should have a "like-new" pump motor when done, provided yours was not totally rusted out in the first place. I have found that the main failure point is the front bushing (where the water lays when it drips into the back of the motor) and filing and oiling the bushing seems to do the trick.

And remember, if you don't fix the leak, or umbrella the pump, the same problem will repeat. Have a look at my post about FWD solenoid valve removal, this will stop the leak, but the procedure is still in beta testing.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby jbviau » Fri Sep 23, 2011 11:12 pm

Dan4111 wrote:So.... Welcome to class.

This teacher deserves an apple!
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby schluets » Mon Nov 14, 2011 11:03 pm

Switch998..thank you!! I discovered your post and this thread just in time as my Keurig was about to opened like a coconut. So to fast forward, the machine is back together and makes coffee. The issue is quantity. From the small cup to travel mug size, each step increases in volume but the travel mug size only puts out about 1.5 cups (measuring cup). At each cup setting, the volume is constant every time. Is this still a matter of the air pump not working as efficiently as it should??

Switch- what is cleaning alcohol? I haven't heard of that before and where would one buy some? Lacking this, I opted not to rinse out the air pump motor as suggested. So I put 3-in-1 on outside bearing, then removed plastic shaft end and carefully tighted cordless drill chuck on end of drive shaft (ie- like the shaft was a drill bit). I spun it slowly for 5 mintues hoping to work the oil in. After putting the white plastic drive piece (not sure of proper name) back on, I could spin it by hand and it would spin/coast for a revolution or so. So I think it spinning freely, but not sure is spinning like it should.

I would be curious on folks thoughts.

Thanks in advance and thanks to all for the great info on this thread.
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby jbviau » Tue Nov 15, 2011 12:10 am

^^^ Welcome!
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Re: Dissassembly + Repair Guide - Keurig B70 Platinum

Postby anon » Mon Nov 21, 2011 7:44 pm

Lots of excellent information in this thread.

I don't (yet) own a B70 but my sister is giving me her recently deceased B70 (minus the k-cup holder) as a project. In preparation of the necropsy, I've read every post in this thread (multiple times) and studied forhoover's photos and EmmJayEff's Theory of Operation document.

Based on my B70's reported symptoms (dead as a brick), I believe my victim was killed by a leaking foward solenoid-air-valve that drowned its transformer. Once I get ahold of the victim's carcass and take some physical measurements I'm going to interrogate the usual dealers (Frye's, Digikey, Mouser, Arrow, Newark, and even RadioShack) in order to locate a compatible replacement transformer. Ideally I'll be able to find one that fits without any plastic surgery to the B70's innards.

R and R-ing the dead transformer is the immediate problem but as an engineer I also have to analyze the root cause of the problem. As was previously noted by others, it seems obvious to me that allowing water into the front solenoid-air-valve is a major design flaw. From what I can tell that valve exists to break the vacuum that's created in the water fill line after the water pump turns off and thereby prevent water in the reservoir from being siphoned out into the water heater. Without some sort of valve or vacuum break in that line, if the reservoir water level was higher, then the water level in the heater would eventually rise to the same level as the water in the reservoir (because all pumps leak when off, that's what water valves are for). Keurig cheaped out. Rather than use a food-grade water-valve on the pump output, they used a cheap solenoid-air-valve tee-ed off the high point of the water feedline to break the vacuum. The engineer that designed that plumbing must have had a brain fart and forgotten that the side port of the front solenoid-air-valve is alternately under vacuum (just after filling the heater) and under pressure (while brewing). While under vacuum it can leak, but while under pressure it has to have zero leakage. If there's a clog in the k-cup needles, then during brewing there will be enough back pressure to cause one or both of the solenoid-air-valves to leak (they both see the same pressure). If the Aft solenoid-air-valve leaks, no problemo because it's just leaking air. But if the front solenoid-air-valve leaks it will (if unfixed) eventually kill my replacement transformer. Therefore, I will correct that flaw by inserting a $2 check-valve from my local aquarium store (or auto-parts store if the aquarium one can't stand up to hot water), into the air line between the front solenoid-air-valve and the water line tee (and put jimmy hats on the air pump motor and my virgin transformer; better safe than sorry).

(note: the pressure sensor in the LCD panel can't detect air or water leaks and shut down the air pump because it can't tell whether the water is flowing into the k-cup or blowing out the seal in the front solenoid-air-valve.)

But all this pondering makes me verrrry curious about some things I wont' be able to answer myself until I open up my dead B70. My question for my fellow hackers is: assuming the Theory Of Op doc is correct that the "Mesh Filter" is on the leg of the tee that feeds the water heater, then where is the fresh air intake for the air pump?

Surely it's not drawing dirty air from underneath the unit???? Without some sort of filter on the fresh air intake, the air pump and the aft solenoid-air-valve (and the water heater) are getting a dose of unfiltered/dirty air on each brew cycle. Yuck!!!

That might explain why some/lots of B70s have problems due to stuck air pumps and stuck air valves. If your B70 is operating poorly maybe it's trying to tell you your countertops aren't clean enough. I think my next preventative fix (besides not allowing any dust or spilt sugar or flour under my B70 while it's brewing) is to tape some sort of filter fabric/cloth over the air slots on the B70's bottom panel. I think cheesecloth might be too coarse and a paper coffee filter is probably too dense (and less than ideal if a water spill runs under the B70 and soaks the filter). I think I need to find some fine nylon screen material.
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