Sup 021ybdr

[Englisch in Perth]

Hi all,
First my apologies, sadly I can not read or write German.
Google Translate is my friend.

I have a Incanto de luxe (SUP 021YBDR) with, I suspect, a broken power board ( P120_PWRV02 ).
Water spray got into the machine from the rear left hand vent.

On inspection it appeared as if R70 was broken ( I think R70 is 680 ohm, it was too damaged to read properly).
I replaced R70 with a 1/4 watt tailed resistor by soldering on to the end of R6 and ISO 11.
I have checked the output of the 5 volt regulator ( IC 1 ), it's OK.
I have checked the two fuses, both are OK.
I have given the power board a pretty good visual inspection. There are no other signs
of damaged components.

The fault to remains.
The only visual symptom is the top line of the display are all black boxes.
None of the buttons respond to pressing.
There is no sound at all when I plug the coffee machine in and switch on the power.

Can you please suggest what I may test next to help with fixing the fault.


I have very good electronics skills.
I have very good mechanical skills.
I have very bad German skills.

Regards,
Englisch in Perth

 

[hmilbradt]

Hi

On your board R70 ist marked on the SMD-resistor with 681 = 680 Ohm.
R70 is part of a circuit thet gives signals to the microprozessor about the status of the mains power (230 VAC). Signals that are vital for booting. The row of black boxes in the display mean the µP does not boot.
Check the opto-coupler ISO 11 . Is it damaged ?

regards
Harry

 

[Englisch in Perth]

Thank you for the very quick reply Harry,
I will take opto-coupler ISO 11 off the board and test it.
This opto-coupler has the following markings on it: -
Su 2
357

This is the same markings as ISO 10.
So if that one has not broken I have a good one to compare ISO 11 against.

Thanks again for the quick reply.
Regards,
Englisch in Perth

 

[hmilbradt]

Hi

You are right. Via ISO10 the µP gets infos about the current the grinder uses.

regards
Harry

 

[Englisch in Perth]

Good Morning,
The story continues.
I have removed ISO 11 from the board.
Using my 8060 A digital multi meter I checked this opto-coupler.
In the diode test mode the LED side of the opto-coupler checks OK.
And the transistor side of the opto-coupler appears OK.

While I had the opto-coupler out of circuit I tried an experiment.
I soldered a wire from the zero volt side of voltage regulator ( IC 1 )
To be exact it was the zero volt side of the full wave bridge rectifier.
The other end of the wire I soldered to the junction of R51 and the circuit pad
where the collector of the opto-coupler ( pin 4 ) would be.
The purpose was to drive this input to the computer board to a low state.
I turned the power on and I still had the same symptoms.
Which is the top line of the display are all black boxes and
none of the buttons respond to pressing.

After turning the power off I then removed this wire.
This time I was testing to see if the + 5 volts ( via R51 ) on this input
would make the computer board work.
It did not work.
I have checked R51 and it is as the marking says which is 272 or 2700 Ohm.

Would it be possible for a suggestion on what can be tested next to
help me diagnose this fault.

I am missing my coffee
Regards,
Englisch in Perth

 

[Englisch in Perth]

An update.
The wire I soldered in from the zero volt pin of IC 1 ( the voltage regulator ) to
junction of R51 and the circuit pad
where the collector of the opto-coupler ( pin 4 ) would be.
At this point the opto-coupler ISO 11 has been removed from circuit.

What I had been doing is putting this wire in place and then turning on the power.
I was getting the same symptoms of the top line of the display are all black boxes and
none of the buttons respond to pressing.

I would get the same symptoms when I removed this wire and then applied power.

What I discovered is if I have an open circuit at the junction of R51 an the pad of pin 4
when I turn on the power I still get the top line of the display are all black boxes.
However if I make contact at this junction and then break contact and do this two or three times
the display would then show "Energy Saving" and the correct time.
However there is no response when I press the buttons.
This is the same if I leave the wire in place or leave it open circuit.

I wonder does a 50 Hertz signal switch this opto-coupler off and on and the computer is detecting this?
I do not know.
I will have to explore the circuit that makes the LED inside the opto-coupler turn on and try to
work it out.
Does anyone know if this is the case.

I will continue to explore.
Regards,
Englisch in Perth