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That was it. When I tipped the machine more water came out than usual and the base tray was wet. I had a look at the float switch, it is a microswitch which needs very little pressure, I suppose that is necessary because it is only a piece of polystyrene that pushes it. Where is the leak? I think most likely the output side of the wash pump which has the different clip on it which I imagine is not supposed to be reused.
I found another wire at the bottom of the door, a thin black one, that was completely broken. Guess where that goes? The wash pump. That means the problem was intermittent contact to the pump secondary contacts, then no contact at all. I rejoined the wire and measured 230V AC on it. On a test for about 20 minutes the machine ran normally. The leak must be a slow one, I will have to see in the coming weeks but for now it is repaired.
Thank you for the help, it was certainly good fun. 😀Since I last posted I was interested to know what voltage the wash pump actually needs to run, which is good to know when trying to work out if the pump is defective or if it isn’t receiving a signal from the PCB. I wrote above that I measured 230V AC on the black wire, but that can’t be correct. This wire is the negative connection going to the pump, which is connected to an 816C opto coupler. This runs from 5V DC. I tried testing this and when you put 5V DC on the input the pump doesn’t run. By the way, when you do this you should put a resistor on the + connection, as the 816C cannot take very high current. I used 1000R. What actually comes out of the Beko PCB is not public information, but I assumed it must be pulsing. I connected up a PWM generator that you can buy for a few quid and 5V at 7.4Hz made the motor run. This 5V measures at about 2.6V on a multimeter because it is pulsing, not constant. I thought the information might be interesting to anyone who wants to know how the pump works because it doesn’t just simply run when you put 230V AC on it as many motors do.
if you alter the frequency does the pump run at different speeds
this is common on some models not sure about beko
Dave
Yes it does alter the speed, but I can’t get it to start at all at lower then 5.4Hz. At 7.4 Hz the pressure is enough to send a plume that reaches almost to the top of the machine with the bottom blade removed.
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