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Had a new Neff dishwasher (cutomer did not want to use Appliance care so would rather pay me, how glad I am of that now) This was a draw line intergrated model that uses a rotary knob/electonic control. The fault was no drain and I thought it would be an easy blocked pump and indeed it was. There is a small inspection panel uner the front of the door through which the pump can be twisted off and when I did this out dropped a piece of glass, great, easy money! Only touble was that it still wouldnt drain out. I tried resetting and even lifting the ‘mushroom’ would not start the pump. I meggerred the pump and it did not read open circuit and the copper windings inside were clean and shiny and after hooking up the meter leads determined there was no feed to the pump at all. I dragged e thing out and checked everything and therefore concluded the control unit US and ordered a new one (£59 odd retail plus the martins favorite tax) I fitted this today and switched on to code the module as per the instructions in the box BANG 😯 (the kind of sharp crack that seems to leave a bad taste on your tongue.)
Fearing the worse I removed the cover of the new module and one of the surface mount components was blown to hell. I then checked the old module and that same component was pin holed. SO small was the hole that no one would ever spot it had they not known were to look. I traced the track from here to the connector plug and yes it was the pump lead. I again checked the pump and it read ok but thought about the resistance reading. I checked first the resistance of a standard Askoll pump off my van and it was 210ohms. I did the same check on the Neff pump in the dishwasher and was astonished to find 0ohms. It was a complete live to neutral short! I have never known a pump to fail like this other than completely burnt out ones yet this one appeared in good order. So I have one scrap new control unit and a customer thinking about even having the job done at all while I was regreetting taking the job in the first place.
The moral is… dont take anything for granted, test and check again as appliances these days bite back in most unexpected ways.Re: newest model Neff and Bosch dishwashers-beware
s4443N8gb08
But pretty much the same as all the Bosch/neff plastic base models these days.
Re: newest model Neff and Bosch dishwashers-beware
Who would ever bother testing continuity of new parts? I bet you do from now on – for a few weeks or months – then decide it’s so unlikely to result in anything that you slip back to just whipping it out and fitting it 😉 And there’s nowt wrong with that. I’ve done it for nearly 29 years and never had such a thing as 0 Ohms on a new part. What a freaky fault!
Re: newest model Neff and Bosch dishwashers-beware
andy_art_trigg wrote:whipping it out and fitting it 😉
Where’s that “Carry On” thread 😆
Dave.
Re: newest model Neff and Bosch dishwashers-beware
Hi all
I tested an plaset useing a 500v megga instead of my ohm tester
(because it was shot) that made it 0 ohms which blew a old hpt spin board 😳 but they were a bit cheaper than that.
? is there a suppreser of some kind in them ?Paul
Re: newest model Neff and Bosch dishwashers-beware
streetlighter wrote:is there a suppreser of some kind in them ?
Paul,
The later series of Plaset pumps now have a TOC fitted against the coils so maybe that’s what you are referring to?
Martin
Re: newest model Neff and Bosch dishwashers-beware
When I replace that pump (and board 😥 ) next week I will take the damn thing apart to see whats gone on. Its a bit worrying that a blocked pump could lead to this sort of expensive repair.
Re: newest model Neff and Bosch dishwashers-beware
I had a similar experience with a Hoover six. Checked the pump for continuity and it was OK. Replaced the module BANG!
Oh dear! was what I said – honest. 👿
When I checked, the pump was short circuit.
On machines using a 100{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} electronic control, relatively low current componants (solonoid valves and pump) are driven by a small triac eg. MAC97A8 rated up to about 1A. These are now largely superceded by similar surface mount componants (eg. ZO107), and this is almost certainly what had blown on eastlmark’s module. These small triacs are usually driven almost directly by the Microcontroller chip.
Anyway I managed to get a look at another module and identified the componants that had blown (the s/m triac and two s/m resistors) which I obtained from Seme. The little suckers were a bit of a pain to solder onto the board because they are that tiny but I managed. Popped it into the machine and hey presto the little darlin worked! 😛
I relate this story to encourage you guys to have a go at things like this. These componants are DIRT cheap (pence) and by the time you have sent for another module you could have had a go. All you need is a small soldering iron, some paste solder, a magnifying glass and a selection of s/m resistors and triacs – easily identified off each module you come across. Total investment about a fiver maybe.
This will earn you a massive wedge of brownie points with your customers when you save them lots of £’s. Not to mention they will think you are a genius. Plus you can get some extra cash for the module repair rather than put it into your suppliers pocket. If it do’snt work – well it did’nt cost you much just send for the new module.
Incidently – if you see any surface mounted resistors (the little black ones with numbers on them) that have 0 on them then these are just links (0 ohm).
Have fun – Andy :wave:
Re: newest model Neff and Bosch dishwashers-beware
My previous attempt at fixing surface mount ended up being slung across the workshop floor in a fit of rage 👿 Might be time to try again though. Thanks for the input Andy.
Re: newest model Neff and Bosch dishwashers-beware
It’s how you do it – I splat ’em into place with a strip of bluetack, then solder the ends.
You do need eyes like a hawk though. Lot of use under water……
😀
Chris.Re: newest model Neff and Bosch dishwashers-beware
Resistors and capacitors are not too bad to lift as enough heat can be applied to the tiny componant to losen both end at once, allowing it to be quickly lifted off. Triacs can be a bit more tricky.
The secret is to use as little heat as possible especially when removing the old componants this ensures that the track does not detach from the pcb. Use a solder sucker to raise as much of the old solder of the pad so that you have as even surface as possible. Put a tiny blob of surface mount solder paste onto each pad then carefully place the triac / resistor onto the pads by sticking it to the end of a pointed instrument with something sticky. This gives you something to hold it in place with while you solder it. Apply minimum heat to each pad in turn until the solder runs. Job done.
A small iron (15W) with a pointed bit is essential, and having a mounted magnifying glass with fitted illumination helps a lot, by leaving both hands free.
Desoldering surface mounted DIL IC’s is virtually impossible without a special wide bit that can make contact with all the pins on one side simultaniously allowing one side to be lifted first. Once bent up you can get hold of it and the second side is easy. The biggest hazard as mentioned is detaching the tracks from the PCB by applying too much heat so be careful.
Even places like QER sometimes do this. I have had NON S/M modules off them that looked like they had been repaired by a partially sited butcher!
Hope there’s no butchers reading this! :eeek:S/M IC’s that have pins on all four sides of the chip – well i would’nt even attempt one!
Andy 😀
Guys, if you’re doing any amount of smd work, treat yourself to one of the cheap gas irons- I use an Iroda 70- and get a hot air tip for it. a mere waft of the tip over the component and you can pluck it off with tweezers. I’ve used this technique with gullwing ICs too, but a bt of patience is needed.
Oh, and plenty of engineers will tell you it’s impossible to work with smds without a hot air rework setup, but that’s £1000 I don’t have, LOL.
david
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