Siemens EQ500 integral percolation unit

Hello,
I have a Siemens EQ500 integral coffee maker purchased in 2020. It works very well but since a few weeks I have difficulties to remove the percolation unit (to clean it) and especially to put it back.
It is regularly maintained (descaling, cleaning, ...) and I do not understand where the problem comes from.
Thank you for your help and advice

Hello, I have the same problem for a few months. There is a possibility to extract it but it is still a troubleshooting. There are videos on YouTube that explain this.

!!! Everyone tinkers at your own risk and responsibility !!!

I have repaired such constructs a few years ago. The problem is with the drive (drive and valve is only one part) and the brew group, this is almost identical in construction to the EQ300, EQ500 and EQ900. Is in my opinion a misconstruction of the highest quality, Siemens has now, as far as I know, more than 5 versions of the BG of the EQ9. That's where the problem lies, the hose, which pushes the powder chamber in one direction. After X-uses, it gets a kink (is still tight) and then the "force" is missing to press the chamber properly. Remedy can be obtained, if you simply turn the hose clamps on the BG up / down. Have once read a report, since someone has a rubber ring hingebastelt, which pulls the cup when driving down / turn then in position. Wonderful MacGyver trick, just looks like tinkering, but the end justifies the means.
But with the EQ500 there are problems with the drive. There the actuator and the valve are one component. The wise thing you see, there is a gear on top that controls the valves and the actuator. That's built so cheaply that the gear gets warped, is no longer round, it becomes oval. The little motor that sets everything in motion has no end of power. When it presses the coffee, you hear this, similar to walking through snow. And there's the problem, the motor has such a force that the gear gets deformed and then skips 1 or 2 teeth. Either new drive, the manufacturer collects a lot of money for such a scrap, or disassemble.
Disassemble:
Disassemble the drive, remove the gear (with the wise thing), warm, make and press a wooden handle into it, let it cool, wood out, and then glue a piece of plastic 2-3 cm thick with the appropriate diameter, assemble and peace is. Pay attention to the correct position of the gears, they must be in a certain position.
When disassembling the device do not skimp on cell phone pictures. Is very helpful if the experience is missing. So no screw is left and the cables are also laid correctly again.

!!! Everyone tinkers at your own risk and responsibility !!!!

Disassemble the drive, remove the gear (with the white thing), warm, make and press a wooden handle inside, let cool, wood out, and then glue a piece of plastic 2-3 cm thick with the appropriate diameter, assemble and peace is


I do not understand... where should there where and what reindrücken?

Today I turned a mandrel d=22.3mm out of aluminum, approx. 2cm long. I then pressed it into the open hole. Without glue, as I tolerated it very tightly. Press it in approx. 5-6mm deeper, as there is a centering on the cover to guide the gearwheel.
I hope that things are now quiet and the machine is running. I've already had it open 10 times, aligned gear positions etc. Nothing helped.
Maybe this is the final solution. The machine was already broken after 1.5 years. BG clamps. Not nice
Oh, the gear wheel was approx. 0.5mm out of round. After pressing in the aluminum, it was 22.3 mm all around.

Update: That wasn't the solution yet.
Since the brew group got stuck once because the wire on the pomace ejector came loose and got into the brewing chamber, the gearbox has probably suffered damage.
It looks good so far, no broken teeth etc.
But I was probably able to find the actual problem: It's the poor tolerances between the gears and the housing. The fit is too roughly toleranced, or everything wobbles. Here 2-3 tenths, and there a little more, plus wear, results in a force curve under high force that causes the teeth to skip. I have turned more bushings for optimization. I will report back.

Info: Only the gearwheel with the driver skips. So exactly the one that naturally drives the brew group.

QUOTE (Kaffeehals @ Thursday, November 16, 2023, 9:56 pm)

But I was probably able to track down the real problem: It's the poor tolerances between the gears and the housing. The fit is too roughly toleranced, or everything wobbles. Here 2-3 tenths, and there a little more, plus wear, results in a force curve under high force that causes the teeth to skip. I have turned more bushings for optimization. I will report back.

Great, I'm not the only one getting deep into the subject of the EQ.500 drive .
Yes, I've had the same experience with a number of defective drives.
Pretty rickety affair, due to the lack of a lathe I tackled the problem with a 3D printer and designed new gears and matching shafts.
I think the cause is more likely to be the tight valve control, there is also visible damage to the gearwheel of the program control. If the brew group is jammed, should there be a skip on the worm drive? So far I haven't been able to detect any major damage, perhaps the brass worm profile is cutting into the plastic wheel, unfortunately I don't have a completely new drive to assess the wear in this area.
I would be happy to discuss this further.

In the meantime, happy holidays and good coffee

Kaffeehas, you have a done a great job diagnosing the problem with the Siemens EQ.500. Everything you have mentioned is part of the problem. But what I have found is that there are a few other things you must do to fix your machine properly. The real problem with this machine is that it has a mechanical design error. Basically, when the brewing unit is rotating to press/ squeeze the coffee grounds the key way on the lead screw can only rotate approximately 2.625 turns as it is raising the plunger and before it reaches its end-stop. However, the program gear (big gear) must turn 2.75-2.80 turns before the stop cam on this gear shuts off the motor. This means that the brewing gear (smaller gear in the center) reaches its mechanical stop before the cam on the program gear makes it to the motor stop limit switch. In other words, near the end of this squeezing cycle the brew unit gear has technically stopped, but the motor continues to run wrenching the brew unit gear for another 20 degrees or so until the program gear reaches its stop cam to turn off the motor. This is why the hollow shaft of the center gear becomes an oval....it is being wrenched because the lead screw on the brew unit has reached its stopping point before the program gear has turned the motor off. And, by having coffee grounds inside the brew unit it makes this situation ever worse. Eventually, the tremendous stress is just too much that center gear jumps a few teeth after things have begun to wear and so that is why the transmission winds up becoming out of sync.
The way to correct this problem is to extend the motor stop cam on the program gear by 22-25 mm so the motor stops earlier (i.e before the brew unit reaches its stop). The transmission gears are made of POM so you can just use some acrylic material to extend the motor stop cam and glue this piece in place with some super glue.
Additionally, please note that the wrenching of the center gear many times will also wear down the center gear’s seat in the transmission housing, so in addition to adding the 22.3 mm dowell you suggested, you will have to add brass shim stock 0.2 mm Thk x 8 or 10 mm W bent around the center gear shaft and then inserted into its seat (at the end of the gear that has the brewing unit key). This will tighten up the center gear and improve meshing with the program gear even more ( just to clarify, the latter shim should be inserted into the middle gear’s seat of the housing and not the gear housing cover).
Lastly, if you find that there has been some wear on the teeth of the center gear, you can rotate this gear 180 degrees where the calibration hole in the gear is on the side towards the front of the machine. This will improve the operation quite a bit too. The above changes will prevent the machine getting out of sync ever again. Hope this helps.

I will just clarify again which stop cam on the program gear must be extended. It is the stop cam for turning the motor off at the end of the coffee grounds squeezing/ pressing cycle (when the brewing cup has been fully raised up). The motor stop cam for when the brewing cycle stops and the brewing unit returns to its home position is okay. So after removing the gear housing cover and looking down from on top of the program gear, you must extend the squeezing cycle stop cam to the left by 22-25 mm. You can also identify the squeezing cycle stop cam by looking at the limit switch it operates. This cam limit switch is mounted on the side of the gear transmission cover and it is not the cam limit switch on top of the housing cover.

I mean extend the stop cam to the left side when looking down from on top of the gear and when the stop cam of the big gear has turned near the position where the corresponding stop limit switch is located.

Hi again,
Just an update to my recent posts regarding the Siemens EQ500 machine. I have now seen a few more machines that have the center gear out of calibration and in addition to all of the changes I have mentioned previously, it may also be necessary to also add shim stock to the seat in the gear box cover for the center gear. After pressing in the dowel that makes this gear's hollow shaft round again you may find there has just been too much wear to this gear's seats at both ends due to all the gear wrenching that has existed in the transmission since new.

Therefore, instead of adding brass shim stock just the end of the gear that has the key for the brewing unit you may have to also add 0.2 mm x 5-6 mm W x the appropriate L shim stock on the top side of the center gear. Since the center gear is a hollow shaft the seat in the cover for the center gear is a male protrusion or boss compared to the bottom seat which is a female hole in the gear housing. This means on the top side of the center gear you will place 0.2 mm x 5-6 mm W shim on the inside of the gear's hollow shaft, that is, this round shim will sit just on top of the dowel that was pressed into the hollow gear shaft. Adding the second shim on the top side of the center gear will prolong having to totally replace the gear box/ transmission for quite some time. I guess at this point I am recommending adding shim stock at both ends of the center gear instead of only one end just to be safe.

Further to my previous posts about the Siemens EQ.500 Coffee Machine I have made a document that includes photographs and description of the changes I am recommending to fix the stuck Brewing Unit problem. You may access this document in the link below. The link is from a complaint I recently registered with Siemens, of which I have already received a positive response back.

https://www.sikayetvar.com/siemens-ev-aletleri/kahve-makinesi-demleme-unitesi-temizlik-icin-cikarilamiyor

@Samdarm
Unfortunately, I could not find a document with the details of your proposed improvements under the link.
Could you please take another look.
Otherwise very interesting to follow the great response.
Another question about the extension of the cam for the limit switch, here a dimension of 22-25mm is given, isn't it rather 2.2-2.5mm?
Best regards
Torsten

tk_0,

Thank you for your comments. I sent you a personal email response on here regarding your question(s). Also, I am happy to send you the pictorial Word.doc with detailed "how to" and explanations of the changes if you like. Please advise email where to send. I am not approved for attachments on here, as you probably already know.