Neff S51M63X1GB constantly cutting out

[benwest]

i have a neff S51M63X1GB dishwasher, 5 years old. it routinely cuts out multiple times mid cycle and having done so goes completely unresponsive — red light off, no buttons working — and can only be woken up by unplugging and plugging back in (and sometimes even that doesn’t work immediately). it turns on by itself now and again, tries to continue with the cycle, there’s a lot of clicking, then the pump (i think) whirrs for half a minute or so, and then it turns off completely again.

i’ve opened it up to see what’s going on. it takes in water at the beginning of a cycle, rinses for a bit, drains the main chamber, fills up the plastic tank behind the left side panel, then cuts out as described. nothing will make it drain that tank, including reset cycles, unplugging etc. so i’ve manually drained it a couple of times and this just happens again. sometimes it cuts out even sooner than the initial fill.

i’ve checked the pump, nothing blocking it (since it successfully drains the main chamber into the plastic tank i dont think the pump is the problem), the drain hose is also clear (well a bit disgusting but not blocked). there’s no water in the bottom either, i’ve taken off the bottom panel to check.

what’s the next step? done quite a lot of googling and searching through the forum but can’t find a description of this particular problem.

thanks a lot for reading this far 🙂

[electrofix]

Re: Neff S51M63X1GB constantly cutting out

take it you have tried another socket to eliminate that

Dave

[benwest]

Re: Neff S51M63X1GB constantly cutting out

thanks for your reply dave, i actually hadn’t but i have now, exactly the same situation.

i’m not sure if this is useful but after a long break (i first tried opening it up a few days ago then left it so it’s been untouched since then) it managed 15 or so minutes of a cycle before cutting out. but after a few more goes tonight of plugging/unplugging/manually draining/resetting etc. it now cuts out almost straight away, sometimes only lasting seconds. this difference is what initially made me think there was a leak or something of that nature, something accumulating slowly, though of course i could be barking up completely the wrong tree.

[electrofix]

Re: Neff S51M63X1GB constantly cutting out

also assume you have checked the mains plug on the back of the dishwasher.

if this is ok sounds like you may have power supply issues on the main rear board

not had one of these boards out to look at so don’t know the board layout. complete new board is about £110

Dave

[benwest]

Re: Neff S51M63X1GB constantly cutting out

thanks again dave. when you say “checked mains plug” im not sure what you mean, it’s a straightforward moulded lead similar to a kettle lead, plugged in firmly. fuse in the socket end is fine, is there some other circuit protection in the dishwasher? remember it does usually work after turning power off and on completely. so as you say a control issue more likely…

if this board something i could remove and inspect myself? or post a photo of on the forum? i’m reasonably competent at opening and fixing things but don’t want to start dealing with complicated electrics.

last question is there anything else like some other fault sensor that could trip the dishwasher in this way. as i said its not the flood sensor in the base, but is there anything else mechanical to check while its all open? thermostat? any other overflow sensors anywhere?

thanks for your help especially at 11pm on a monday! much appreciated. ben

[electrofix]

Re: Neff S51M63X1GB constantly cutting out

moulded plug I was talking about just making sure you had covered all the loose connection bases

as you can imagine I don’t know everything but as far as I know there is no sensor that will cause this. From what you say you are losing all power unless you turn it off and back on. assume you mean turn it off at the socket and the power button is also inoperative.
somewhere on the board at the back is a power supply that converts mains voltage down to about 12 that the electronics need. It my guess this is not working properly

you can post pictures and I will see what I can spot as I have as yet not had one of these boards out

Dave

[timdowning]

Re: Neff S51M63X1GB constantly cutting out

Eliminated any door closure issues as well by pulling the machine forward slightly out of its housing…

[Martin]

Re: Neff S51M63X1GB constantly cutting out

Agreed, sounds like door magnet problem. Specifically the decor door and floor levelling issues causing door switch to go on and off randomly a likely cause.

[benwest]

Re: Neff S51M63X1GB constantly cutting out

thanks tim and martin. before i investigate dave’s suggestion (which is obviously going to be quite a task) how can i fully eliminate a potential door magnet issue? the dishwasher is in the middle of the room with its sides and decor door already off. where is the door magnet switch which could be causing an electrical cut out? centre top near the latch? when i get home again i will try and hold it shut or subtly relevel it etc to see if i can get any such change to make a difference. ben

[electrofix]

Re: Neff S51M63X1GB constantly cutting out

switch seems to be at the top of the door

go here
http://www.neff.co.uk/store/spare-parts

put your complete Enr in ( yours has the 2 end numbers missing )

parts diag 2 item 0245

door switch once disconnected can be checked by a muti-meter on low ohms scale

Dave

[benwest]

Re: Neff S51M63X1GB constantly cutting out

much appreciated dave, will take a look this evening and post back here afterwards

[benwest]

Re: Neff S51M63X1GB constantly cutting out

removed the door sensor and the reading across it is around 70 kOhm. what can we make of this? if that rules this out as a fault and we are back to the power supply suggestion could you let me know which part number on those exploded diagrams you were referring to and i’ll try and get at it (and get some pictures).

by the way the full dishwasher code is S51M63X1GB / 52 (as dave says these extra digits are required by the neff website)

thanks again all

[electrofix]

Re: Neff S51M63X1GB constantly cutting out

switch closes with a magnet.
so find a magnet and with your meter connected move the magnet to touch it then away again and the meter should change

bit worried about the 70k ohms when open. it may be correct as they may have put a resistor across it inside. but if no resistor would expect a lot more

Dave

[benwest]

Re: Neff S51M63X1GB constantly cutting out

ah yes of course that’s what you meant, been a long day…

it actually doesn’t change when presented with the magnet from the machine itself. so this suggests a fault in the sensor i assume. but in your opinion could this explain the behaviour of working intermittently and sometimes turning on and back off itself, occasionally getting part way through the cycle, responding temporarily to plug-pulling etc…? surely if the sensor doesn’t read closed at all it won’t allow the machine to operate at all… or have i misunderstood something obvious about its controls?

thank you again for walking me through this.

by the way the reading is actually 70kO one way round and about 25kO the other way round, with and without external magnet.

[benwest]

Re: Neff S51M63X1GB constantly cutting out

hi again before i order a replacement door switch could anybody who knows more about this sort of thing suggest whether the intermittent behaviour is consistent with a switch which doesnt seem to read closed at all? it seems to be that the machine shouldnt work at all in these circumstances. thanks 🙂

[Author]

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