Neff oven clock reset E-nr B1ACE4HN0B/10

[trotter]

Customer has two single ovens side by side both Neff B1ACE4HN0B/10 FD9901
multi function oven with a manual selector and separate thermostat. If I turn the selector to the oven light position everything is fine, as soon as I turn selector to ANY other position the clock display ‘trips’ as if there has been a power interruption (the clock display flashes 12:00) and the clock then has to be reset.

There is no problem with incoming supply and I have megger’d all the elements both fan motors and lamp holder. One of the ovens does this every time, the other oven does it very occasionally and if I turn that oven selector very slowly it seems to be okay.

I have tried bypassing the clock relay on the board – still the same fault. I am assuming it must be a selector switch fault BUT it seems odd that two ovens are doing the same thing and they are only a little over two years old!!

Any thoughts much appreciated!!!

[Hollytree_Technical]

That definatley sounds like an odd one but there are a couple of thoughts going through my mind on it, without a wiring diagram I will have to make some assumptions from the parts list and based my suggestions on that:
It sounds like it may be an induced electrical noise issue on the low voltage side or that the selector switch is shorting out the low voltage supply briefly.

1. Make sure that all the ground wires to the board are properly and tightly connected – a loose ground could cause some strange issues for the module.
2. Make sure that all the low voltage control wires are as far as possible from any mains voltage wires and if possible only cross at 90 degrees.
3. Try disconnecting the cooling fan and see if it still does it (any coil will potentially create a noise electrical spike when first powered up).
4. Disconnect the low voltage control cable from the selector switch end and see if it still trips when you turn the switch.

Jem

[trotter]

Thanks for the thoughts Jem,

1. I’m pretty sure they’re ok …..
2. ?? not sure
3. I am fairly sure I did that and because the cooling fan is running with the lamp on I didn’t see that as a potential issue.
4. Definitely tried disconnecting that cable and no difference.

It could be an earth fault on the supply I guess, given that it effects both ovens REALLY strange and annoying fault!!!

[Hollytree_Technical]

trotter wrote:
1. I’m pretty sure they’re ok …..

I assumed that you had checked them but it is always worth making sure.

trotter wrote:
2. ?? not sure

If this is an induced electrical noise issue then seperating the signal cables as much as possible could well reduce the issue.

trotter wrote:
3. I am fairly sure I did that and because the cooling fan is running with the lamp on I didn’t see that as a potential issue.

When I suggested this one I had assumed that the cooling fan didn’t run in the lamp only position but if it does then it is far less likley to be the cause.

trotter wrote:
4. Definitely tried disconnecting that cable and no difference.

If you have tried it with it disconnected at the switch end then I would also try with it disconnected at the board end, in fact I would try disconnecting all the low voltage cables/sensors that you can and see if it still does it.

It could be an earth fault on the supply I guess, given that it effects both ovens REALLY strange and annoying fault!!! What sort of earting system do they have in the house – are they on an underground supply cable or is it overhead line?

Do you have a photo of the module (and/or even the inside of the control panel) available as I can’t find one on line and I am trying to work out how much control of things it has got. It sounds like some sort of switch filter capacitor may have failed, if the board has got control of the individual elements then I would try disconecting them one at a time to try and narrow down if it is linked to a specific line.

Jem

[trotter]

It was the timer boards!! faulty capacitors :rolleyes:

[Author]

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