Nivona 750 code 8 - the brewing unit is jammed, the motor turns only one way

Hello
I am asking for help in diagnosing the defect of the seemingly obvious error code No. 8 "Brewer jam" in the 8-year-old Nivon (CafeRomatica 750). Unfortunately, I have to write down a bit before asking the experts. The problem appeared after another failure of the electronics, which was manifested by immediate shutdown -> damaged elements IRF7103 and IRF7306 responsible for the operation of the engine. I have already routinely replaced these systems (because it is the third such fault at intervals of several months) - the electronics came to life, but I did not remove the jammed brewing unit and after restarting, the error code 8 appeared, i.e. jammed or damage to the brewing unit drive motor.

So I unplugged the "brewing unit" plug, turned the motor back and managed to remove the brewer (after maintenance it works lightly enough), but the error code 8 has not disappeared. I noticed that after turning on the coffee machine, the motor makes only a half turn of the brewing unit forward and does not move back as usual. Another turning on and another part of the forward rotation and code 8. The test of turning the motor on the external power supply in both directions works (200-250mA and 1200mA at the ends - without the brewing unit).
Questions:
1. Does the Nivona 750 have limit switches or only the electronics has an overload switch?
2. What is responsible for the movement (forward and reverse), i.e. stabilizing the position of the brewing unit's axis after turning it on?

Did you find the solution? I have a similar problem ...

Unfortunately not. In addition to these IRFs, I replaced transistors (double switches) A7 (BAV99LT1G) as well as prophylactically Zener 27V diodes (although they broke through at 28V, i.e. they were functional). Still at the start it turns only one way (reverse polarity to the nominal on the cables, i.e. red is minus, and black plus) and there is no characteristic change in RPM (according to the start procedure).

Actually, the machine has been out of use for over a year, but the above question has provoked the dusting of the topic.

Can someone after the hints suggest what element with similar DC motor direction control systems is responsible for changing the direction? This must be hardware, not software fault.

And micro switches (or switches there)

The terminals were checked before - on the "Brew-Unit-Switches" plug and measurements on the board -> all 4 switches respond correctly. Because the espresso serviceman I talked to today 90% bet on the drive fault (persuading me to replace it: PLN 500) - I also undressed it and lubricated (photos) additionally replacing the limit switch (red cable) with the one less used than the "brewed brewer" (yellow ). After drive maintenance, current measurements slightly fell to 100-120mA at 12V and 1.2A at the ends.
Unfortunately, the symptom of turning in one direction only and error 8 after heating up still appears.
I still tried with the red limit switch disconnected - the turnover was longer - almost to the end. This indicates that the signal has an effect.

If there are no ideas yet, I will give up, and this grateful coffee was ...
I feel that there is a small thing, unless the program from Atmedze misinterprets the signals or the "Buy New" mode is activated

Could someone borrow a service or schematic, after all, it's already an old model?

How many coffees are made in the coffee machine, how many descales, what "runs" ?.

Ill have the same problem on a 670 but the harware is more ore les the same . Ill have a "workaround"!!
Stil seaching for the real foul that creates the problem. First clean the whole machine.
Than you can contineu with the below step.
When the machine is start and the foul is displayed the machine is switching itself off.
Now continue the next step 5X (5times):

Push to start the machine (main switch) you here the drive make nois, when the nois stops PUSH THE BUTTON TO STOP THE MACHINE.
----------> After 5 time doing the above steps. WAIT AND DO NOTHING.
The drive brings itselve in the correct position.

For me it is clear that a component on the controll board is defect.
After doing the above steps the machine is making its great koffie.
I have preset (in settings ) the auto switch off to max. I have solar panaels on the roof

Hello. Everything points to a problem with the drive. It is best to substitute a working one from another model. most likely the engine fails to obey. Greetings.

Hello, I asked about the mileage for a reason, please assemble the drive without the motor and gears only with the main wheel and turn it, it has to spin slightly in both directions, they like to blur in the housing.

Hello,
I will dig out the topic because I have the same symptom in my Nivona and I do not want to part with my favorite coffee machine.
I turn on the power button and after a while error number 8 pops up and turns off.
I will press this power 3 times and the third time it heats up and makes coffee without any problems. This situation has happened to me twice already. Do you know what the fault is? Engine?
I have never had problems with him. Age 3-4 years. I can refill the "number of coffees" when I am at home.

FYI: there is a risk, with error 8 - if it is, for example, a seized drive - that several attempts to start the coffee machine will damage the electronics

@rowak, if it is a drive, it would indicate the low quality of the brewer designed, as I read from the thread, rather a factory defect. Previously, I had a stainless steel Zelmer that was designed in such a way that the motors were not in contact with water / coffee. I would buy the 2nd time, but Zelmer withdrew from automatic coffee machines - strange why.
Well, I guess I will have to spend some weekend disassembling it and cleaning it. The problem pops up sometimes today with 2 inclusions, 0 errors.
4446 coffees - is it a lot or a little?

5k of coffees - that's enough to cause any problems. Yes, in this design, the problem with a seized drive is reported from time to time, but IMHO is not a design defect, but series production. Whether this is the case, I am not able to determine at a distance - there may be other reasons as well. And it's not a matter of water getting into the engine, but a 'swelling' of the plastic. Plastics have dominated household appliances for a long time - also in Jury for a few thousand.

Drive motor to be checked. I don't know how this is possible, and I haven't fully confirmed it, but on one occasion it looked to me that a worn motor might behave the other way around in terms of polarity. I will not give my head for it, maybe someone will confirm, but I will give you a hint, because what if it will be some kind of trail. If this were the case, turning the drive in the wrong direction at startup will result in error 8. It would be best to substitute another motor, even if used.
At the same time, as colleagues write, it is worth taking a closer look at the operation of the drive. They like to blur. It is worth to sand the spindles of the wheels with fine sandpaper in places where they pass through the drive housing and lubricate them. A hard-working drive can damage the electronics, including the incidence of one or both IRFs, which in some models will also be manifested by the message 'no tray'.
Regards

I wrote above that I had such a message myself, but it was not always displayed every coffee.

I started to clean myself very thoroughly but after my cleaning for a week the message no water was displayed, even when there was water.
I gave it to the site.
The service said such a message does not pop up (no water) - it probably dried up thoroughly before they took care of it and the sensor started working.
As for the error code 8, the problem was not the engine, but some element of the brewing unit, unfortunately I do not remember which one.
The service repaired, probably replaced the seals because he said it wears out and I regularly have to replace it every few thousand coffees.
Maybe it will help you.
Or maybe the error code pops up when the motor is too heavy and detects too much current due to (e.g. worn brewing seals or motor problems). I don't know if you need any more help but here I would be looking for you.

My expres after returning from the website does not have this error, but it shoots (noise) that I am afraid that they have broken something. I still have to undress it and look at why it is brewing at work, there is one strong crash always. Something rubs unlubricated, probably.

I have a similar problem, error No. 08. When I try to start the machine, it immediately turns off reporting an error. On the third or fourth attempt to turn on, the test passes and continues to work properly. The next day I did so that before turning on the coffee machine, I thoroughly rinsed the brewing unit and installed it when wet. There were no problems with starting it, it was tested and the coffee was just as good as before.
It turns out that the problem is not worn or blocked, and this was suggested by the service (minimum PLN 350 parts) and the seized brewing unit which should be thoroughly cleaned and treated with grease for PLN 10.
However, continued use without lubrication may actually damage the brewing unit drive.

Hello
He'll warm up the topic.
Nivona 778. 6 years old. 7.5k coffee
After making coffee, the brewing unit is stuck in the upper position. Error 8 popped up and went out. I took it apart, cleaned it, and the problem is still there. The motor shuts down from overload, locks on the drain valve lever and crashes 8ke. Without a lever and a brewer, there is also a bug. Only when it turns like in the video, you can do something. Even coffee succeeds, but it doesn't come back and the same thing all over again. Surely the gasket on the metal strainer of the brewing unit needs to be replaced. But that won't fix the error. Replacing the entire transmission will give something?

The 3-way valve was leaking and probably flooded the engine. Replacing the valve and gear did the trick.

Hello everyone who have a problem with nivona error 8
I have, or maybe I had
The mechanism of the engine reached such a point that it could twist a finger until it broke the plastic.
The first thing I did was replace both limit contactors because it would fit that instead of stopping the motor kept spinning. Until lockout and error 8
After replacing the contactors, the same thing continued, I decided to dismantle the entire gear mechanism in the engine.
And as my colleagues write, one large black gear does not spin in any way seized in the housing.
Sandpaper good lubrication and it's ok.
Now I will test whether this is the end of my ills.
Excessively that before I came to this, disassembling the express 20 times. After each submission he made a few coffees and back the same ?
I hope this helps someone
To disassemble the housing mechanism, you need to remove the large wheel which is next to the two contactors and the third screw is under it. The rest is done fine

At the end of December there was a problem and error 8. The problem was that once the coffee machine turned on, others displayed an error and turned off. In the end, I sent the device to the service for a month, before the end of the warranty. The service replaced the mechanism but noted that the repair was conditional due to traces of moisture inside. I take care of the machine, I wash the mechanism every 1-2 weeks on average. It's strange that such a glitch occurred after such a long time. What's worse, a month has passed after the repair and the error has reappeared and appears sporadically. When the machine is cleaned, the mechanism is rinsed ok. As 1.5-2 weeks pass from washing, error 8 appears every time you turn it on. I pull out the brewing unit, rinse it, lubricate it and until the next error in 1.5-2 weeks. I don't know whether to return it to repair to another service? whether to advertise a repair in Pruszków? at an authorized service.

batot wrote:

My express after returning from the service does not have this error, but it shoots (noise) that I'm afraid they screwed something up. Waiting for me to undress it anyway and look at why there is always one strong crack at work. Something unlubricated probably.

Once, the wife got into the machine and cleaned it so thoroughly that nothing shoots and nothing rubs.

So gentlemen, I see 90% of failures are the lack of systematic cleaning of this model of these models.
You have to clean from the bottom with a brush, sticks, etc. or disassemble the whole thing - whichever you prefer.

@adorato1
I see you have the same symptoms as mine. Not always, but every coffee error no. 8. Read everything I wrote here in the thread.
You probably need to replace the damn thing, I don't know what it's called the brewing unit gasket assembly or something like that. This is used every few thousand coffees and the service informed me that it needs to be replaced regularly.
If anyone here from the site can tell me the exact name of these gaskets, please.
I do not know where you are from, but if you are from Silesia, then in Rybnik I can highly recommend the service:
Marii Skłodowskiej-Curie 7, 44-200 Rybnik, unless the service technicians and the owner have changed. Honest, inexpensive, sometimes you have to rush as they are swamped with work and repair NIOVONA without a problem.
The upside is that they only repair Expresses, so they specialize in that.
I will say more. One man specializes in NIOVON, others from other brands, so sometimes you have to wait.

The only thing that helped me was to grind the plastic pinion that turns the brewing unit, because it was blocking on the microswitch side. Cleaning and lubrication alone did not help.

>>21177638 .
Can you throw up some pics of what this pin looks like after/pre modifications?
It's notoriously blocky for me with coffee inside and cleaning, so I probably need to get the manufacturer to fix it.