Beko Dryer Lamp Flash & Moisture Sensor ( DPU 8360 W )

[McKenna32]

Evening all,

Just bought a second hand Beko Heat Pump Dryer and have a couple of issues with it:

1) The moisture sense/auto-stop feature does not work - i.e. stops after 5~10min claiming it's finished. (only Timed drying works, and works fine apparently)
2) The inside lamp flashes all the time the door is open (and who knows maybe when closed!)

Regarding 1), I've had the sensor off and cleaned it, PCB out and cleaned it, checked electrical continuity between bars and PCB traces (confirmed) and run some wires out to measure the voltage on the bars while the machine is running (basically nothing - ~50mV DC, a few mV AC). I've not got an isolation meter to-hand but plugged in a small meter says 140kOhm across the bars.

So it seems like a PCB issue I thought.

But then, how about 2) - I guess it is the lamp module that has given up the ghost...I don't really care too much if the lamp flashes, but, is there any chance it could be a signal from the lamp module to the PCB that's missing, and causing the moisture sense/auto-stop feature to be turned off?

It's a bit of a long shot - the machine only runs with a closed door as you'd expect, so if that's fine then moisture sensor should be powered up too...So I'm back to assuming it's the PCB. Anything else to check before shelling out for a new one do you think?

There are no error codes

Thanks in advance!

 

[jj4091]

Might help if you have not already seen it https://www.ukwhitegoods.co.uk/foru...um/864317-beko-dsc85w-interior-light-flashing

 

[McKenna32]

Thanks I'd not seen that. It does sound like the exact same combo of flashy light and no moisture sensing which is interesting...A shame they never completed the thread...It's a different model but looks like the same smart lamp card and a related (not the same thou) PCB

If I could sharpen up my questions a bit

1) Could lamp flash and no moisture sensing have a common root cause or are they basically completely independent functions and I just have a boring old coincidence?
2) What should I be measuring at the moisture sensor bars? Is it a capacitance method like a soil moisture sensor? (I think they measure the charge time of an RC circuit, the capacitor being on the board). I am wondering if I can ID the broken chip that's supposed to drive this, or the broken reference capacitor, whether I can just replace that chip. They are all through-hole components so should be an easy hand solder job
3) What is a smart lamp module anyway? What's it for? My guess: you can't see the light fitting, so you might touch the (240V) contacts when groping around to change the bulb...so it doesn't power up the light fitting until it confirms a plausible resistance is in there?? Could it have the wrong bulb in, and the flashing is it "pinging" the bulb to check the resistance? This is a complete swing in the dark though and likely a complete fantasy...

I like mysteries, but I hate unexpected ones that crop up in a dryer that wasn't supposed to have any...

Cheers!

 

[jj4091]

Sorry can't answer any of your questions as I have no experience of Beko products & not much of recent ones that appear to be coming unecessaryly complicated.

 

[McKenna32]

Going to have one last go without all the word salad I seem to be so keen on adding recently:

1) Can lamp unit failures cause the moisture sensor to be disabled?
2) What measurements should I get from a "working" moisture sensor (volts, amps, whatever) and has anyone successfully repaired just that part of the circuit by replacing chips/caps etc.
3) (out of interest) why is there a smart lamp module anyway as opposed to a simple lamp on a door switch...

If I have a eureka moment I will tag it onto the end.

Cheers!

 

[jj4091]

Perhaps Beko might be the right people to ask your questions of. 0333 207 9710

 

[McKenna32]

My guess is they'd rather sell a new one, given that they don't publish anything at all useful regarding machine repair online and the usual corporate avoidance of giving fools new means to electrocute themselves and sue. But maybe I'm too cynical, thanks for the suggestion!