Smeg DWD64SSE Dishwasher, no error code, won’t start.

[perdrix]

The subject about says it all, the lights on the right hand side of the panel flash the program number I’ve selected with the rotary selector.

If I press start nothing seems to happen apart from solenoid like clunking sounds from the underneath (the one by the water pressure switch). It doesn’t fill or activate the drain pump (well it let a small amount of water into the side tank once).

No error codes as described in the manual are displayed.

I’ve checked both the drain pump and main pump for blockages, and the motor start capacitor on the main pump is good.

Mystified! I can read a circuit diagram, work on kV supplies, but Smeg won’t let me have a service manual, schematic or debugging flow chart. Grrrr!

[Penguin45]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

Door lock/switch mechanism can prevent the cycle starting.

Penguin45.

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

The door lock microswitch is OK.

Nothing happens if the door is open.

If the door is shut, it definitely does something, but not normal behaviour.

[Penguin45]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

Hmm – not hopeful. Better have a read of THIS. Quite a few possibilities, which ultimately lead back to the pcb.

Penguin45.

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

Thanks for that, however the page you pointed me to looked like the start of a write up. It stops just at the point where it might get interesting. The last text I see says:

If you wish to carry on with the diagnosis, remember, power off for anything other than observation.

I’m quite OK spending the money for a refurbished controller from QER, if that is the problem here, but I wouldn’t be over happy if I replaced the PCB only to find it was still doing exactly the same.

So any other stuff to check before replacing the PCB?

Thanks
Dave

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

OK now we’re getting somewhere.

I removed the PCB, and R38 is totally cooked, and I suspect that transistor Q8 is shorted.

The question is: Is this the cause of the problem or the side effect?#

Anyone out there who knows these controllers, or at least knows what is driven by Q8 (so I can check for shorts)?

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

FWIW, Q8 isn’t a transistor at all, it’s a MAC97A8 triac, and the resistor R38 is between the gate and the processor. I hope the resistor burn out protected the processor which is upstream from there.

I’ve got one of the triacs on order.

Dave

[gegsy]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

But what does the triac drive?? The component it feeds may have gone down, so replacing triac and resistor without a little fault detection may result in same scenario.

HTH

Greg

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

Indeed a good question which I already asked (above). As I don’t have a schematic of any sort, working out what it drives is an “interesting” problem. I suspect that this is not really a problem (unless the load has gone dead short) as the triac probably died as a result of an inductive kick too many.

The question in my mind is: Once the gate circuit was exposed to mains live as a result of the MT2 to Gate short, was the processor also fritzed as well as the resistor? After all, the current that burnt out that resistor had to go somewhere …

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

The triac connects to B4 on the board edge connector, which in turn leads to the softener solenoids.

Not exactly my prime suspect when thinking of a circuit that would blow a triac, but there you go. Sometimes parts just fail for no clear reason.

Dave

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

I replaced the blown triac and resistor on the control board, and put it all back together.

Now none of the lights on the front panel come on apart from the mains indicator.

Looking at the softener which was connected to the blown triac, one of the two solenoids is open circuit, and the triac probably died when it went open.

Looking at the spares breakdown, it looks like the softener is only sold as a unit, and the solenoid valves are not available separately – is that right? If so that’s rather bad news. I can reasonably pay for a refurbished controller board, but don’t really want to also replace the whole softener.

To remove the softener I assume the drill is:

1) Remove side panel (done that before)

2) Remove hose from softener to diverter valve

3) Unscrew top mounting ring of softener

and out it comes. Is that correct?

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

I replaced the coil on the solenoid valve that had failed, and the timer PCB has gone off to QER to see if they can fix it.

Only other source for the timer (Smeg p/n 696290705) I can find is Servevast (Smeg Service) who want about £133 for it. UK Whitegoods shop says not stocked any more …

Does anyone know of alternate sources for these boards?

Thanks
Dave

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

I got the board back from QER, and have fitted it.

On power on the LEDs for the selected program come on and the drain pump runs for a few seconds, then there is a beep and LED 1 and LED 3 (counting from the left) come on.

No further activity. This doesn’t seem to match any of the error codes in the manual.

I’m hoping this is something simple and cheap 🙂

[perdrix]

Re: Smeg DWD64SSE Dishwasher, no error code, won’t start.

Well, I tried “Press Start 4 times” with the door open. I don’t know if that Reset command is supposed to work with this model, but whatever, it is now happily running a Quick Wash cycle.

Yeah! Thanks to QER.

Now to get some screws for the door – another topic for that though.

Thanks to everyone who chipped in to help both here and also “offline”.

[Author]

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