Electrolux-Washing-Machines EWF 1234 doesn't start, Hints t

[TechMate]

Hello! I am stuck, please help me finding a solution.
Our washing machine one day just didn't start the washing program.

As any washing machine it starts the washing program cycle with the draining phase. Then the prewash water filling phase is supposed to take place, but the machine just stops and it's showing a ”0” (zero) on the screen.

The rinsing program cycle works fine, both draining and filling phases are running as usual

Consequently: There is nothing wrong with the magnetic valve., as the water filling function of prewashing and rinsing are carried out by the same magnetic valve.

Then I suspected the door lock mechanism being the culprit, as such failure seems to be common on washing machines.
I took it apart, checked it, found nothing wrong and fitted it again. The machine work, but only for one wash, then it was back to the same error as before.

I took out the PCB in order to follow the connections and look for signs of disconnections.
I found black soot or dust on both side of the card in the area of transforming high tension to low, and also on the inside of the container.
I could not see any burned component. I cleaned the card with electronic spray and assembled all again.

The machine worked again, but only once.

I went to this site and found the following link to the proper manual.
http://www.manualslib.com/manual/738815/Electrolux-Washing-Machines.html?page=58&term=e34#

I run the diagnostics according to the manual and I got the error code 34. (Search for E34 in the manual)
Alarm E34
Description
Incongruency between level of electronic pressure switch and level of anti-boiling pressure switch 2 (duration of fault at least 60 seconds)

Possible fault
Hydraulic circuit of pressure switches; Electronic pressure switch; Pressure switch; Wiring; PCB;

Action/machine status
Cycle blocked with door closed

Reset
OFF/reset

I have now checked the following:
1. Hydraulic circuit of pressure switches
There are two rubber hoses down to the same place at the bottom of the machine.
I have blown and sucked the hoses. They are free.
Starting washing program cycle with both hoses off (pressure=0) is still giving the same error.
2. Electronic pressure switch
It's a device that converts the pressure in the hose into controlled frequency. At start, with the machine empty the water level 0 and consequently the pressure 0 as well, it should give the max frequency, which is 45 Hz
I have been trying measuring it with a non contact detection meter, but I get too many 50Hz frequencies from the mains, so I do not get any reliable reading.
I have, however, checked the functions with and without blowing into the pressure switch..
Trying to start the program cycle without blowing. Pressure = 0. The machine stops after draining phase
Blowing into the pressure switch locks the door and lits the pilot lamp.
3. Pressure switch
I have checked the 3 switches of the safety level pressure switch.
Default values, that is when machine is empty (level 0) and with pressure applied:
> stand for “connected to.
Pressure = 0 11 > 12 Yes correct *) Pressure applied 11 > 14 Yes correct *)
Pressure = 0 21 > none Yes correct *) Pressure applied 21 > 24 Yes correct *)
Pressure = 0 31 > 32 Yes correct *) Pressure applied 31 > none Yes correct **)
*) Correct according to diagram in enclosed manual page 38.
**) When blowing hard the 31 disconnects from 32
Summary: All switches function properly.
4. Wiring
Bad contact somewhere? Probable but how to find it?
5. PCB
How to test the the PCB?
Is there a way to inactivating the alarm and safety system, for testing only?

Is there anyone who can give hints on how to go on?