Electronics > Repair

Ankarsrum AKM6230 1500W repair

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Marek85:
I have a regular oscilloscope with non insulated channels. But I could always connect the GND to the GND of ATtiny861 that is on the board right?

Few days ago I tried supplying +5V rail externally but I didn't observe anything special on the uC or at the triac gate. Only see static +5V signals like I'm measuring some pullups or just plain GND. But the uC can have some safety mechanisms that in case missing AC voltage he will just go into failsafe mode and not trigger anything. It think since there is no DIAC on the board the uC measures the zero-crossing points. For measuring the board under AC I need to prepare some cables and solder in the old R24 (0 Ohm) because I don't want the 27 Ohm to blow up on me :)

My colleague said that to check if the ATtiny861 works at all I could solder it out and check if I can read signature with a programmer?

PS1: I hope the spare part shop will come back with some good news :)

PS2: I started also thinking If I can get my hands on some sort of off-the-shelf controller suited for the 1500 W motor that has also the feedback loop circuitry. I think its called the PID controller right?

tunk:
Probably not your problem:
Recently I repaired a magnetic stirrer where the
trimpot/potentiometer for RPM control was broken.

Swake:

--- Quote from: Marek85 on January 07, 2025, 02:27:52 pm ---I have a regular oscilloscope with non insulated channels. But I could always connect the GND to the GND of ATtiny861 that is on the board right?

--- End quote ---

NO !!

The 'GND' of the scope is connected to the earth in the mains power plug. The 'GND' of the ATtiny is on another potential. So the risk is to blow up the scope and of course to blow up yourself too.
Actually from the schematic in your message #7 the N wire is connected to +5V. So no... don't connect those 2 'grounds'. Same (confusing) name, but 2 different things.

The 5V injection is a good idea. Without mains power of course. You might want to look a bit further to see if that thing is still alive or not.
Trying to read the program in the ATtiny is an interesting path, note that it might be protected.

You would be very lucky finding a controller that matches the input (the sensor) and the output (1500W motor). The control loop can be made of different methods. PID being one of them. Another possibility is to use that 'dimmer' and let your wife turn the knob when it is too slow. That is the simplest loop you can have.







Marek85:

--- Quote from: tunk on January 07, 2025, 02:52:25 pm ---Probably not your problem:
Recently I repaired a magnetic stirrer where the
trimpot/potentiometer for RPM control was broken.

--- End quote ---
The RV1 blue potentiometer in circuit behaves very weird. It is a 47k potentiometer and in circuit I measure only weird stuff but when I desoldered it seem to be fine. It measures 41.6k not exactly the 47k but I think good enough and it goes down to about 36 and 44 Ohm depending which side I measure.

Marek85:

--- Quote from: Swake on January 07, 2025, 02:54:04 pm ---The 5V injection is a good idea. Without mains power of course. You might want to look a bit further to see if that thing is still alive or not.

--- End quote ---

So I injected 5V into the board and measured around the ATtiny with multimeter since no dynamic (PWM, CLK... etc.) signals are there.
Current consumption is 57 mA.

P01 = 0.3 V
P02 = 0.2 V
P03 = 0.2 V
P04 = 0.0 V
P05 = 5.0 V
P06 = 0.0 V
P07 = 3.5 V*
P08 = 3.5 V
P09 = 0.2 V
P10 = 5.0 V

P11 = 2.5 V
P12 = 2.5 V
P13 = 0.0 V
P14 = 5.0 V
P15 = 5.0 V
P16 = 0.0 V
P17 = 0.3 V
P18 = 0.3 V
P19 = 0.0 V
P20 = 5.0 V

*- PIN7 = XTAL1 toggles only when I connect the probe. When goes to LOW then current drops to 5 mA. It looks like the uC is working (current = 57 mA) but additional capacitance of probe will throw the internal oscillator off balance and uC stops working and current drops to 5 mA.

I also tried to feed a PWM signal to the speed sensor input at PIN14:
PW =  10 ... 90%
50 ... 200 Hz
Upp = 5 V

But no reaction.

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