Kilhamaig Design - door lock

  • AEG Washing Machine Door Latch-Update

    If you have an AEG L64810 washing machine you may well find that after a few years the error E40 crops up at the start of the cycle.  Use of your favourite search engine will reveal that this is the machine telling you that the door is not closed. Of course that does not mean that the door isn't closed, it is just that the machine cannot confirm that this is so.  The culprit is the door latch module which is pretty easy to remove, just whip off the top of the machine - you have unplugged it haven't you? and you will see it lurking just to the right of the opening. Unscrew those likely looking cross-heads at the front and you can lift the module up with the loom.  

    As mine packed up on 23rd December there was no chance of ordering a replacement so I thought I would have a look inside.  What a complicated beast!  There is of course a solenoid which activates the latch and a pair of over centre contacts so that the machine can see that the door is latched.  The solenoid has one of those wire track ratchet mechanisms which means it need to activate once to the lock and the door and again to unlock it.  Also lurking is a small disc of material which appears to be in series with the solenoid and under that a bi-metallic strip.  It's a bit of a guess but I think that this is a PTC which means that the solenoid gets a good whack of current to pull in but then it is reduced as the PTC heats up.  The hot PTC triggers the bi-metallic strip and this prevents the door unlocking until it has cooled down.

    A quick look at the over centre contacts revealed the cause of the trouble, a classic melt pattern showed that the contacts were simply not rated for the job.  A gentle caress with a contact file, these a very soft contacts, and all is well.  I have ordered a spare part just in case, a stupefying £57 from AEG or £15 from A.N. Other spares.

    Come on AEG (Electrolux) it doesn't cost any more to use the correct contact material - cheapskates!

    August 2017

    After 7 months my temporary repair has failed - so in with the new part - totally different, will it last?? - and time to dismantle the offending latch and take some pictures.  Here is the complete beast

    The black part with the metal latch is fairly easily removed with gentle application of a couple of screwdrivers to the classic taper latches.

    A few more latches on and the internals are revealed...

    At the bottom you can see the "biro" type latch mechanism driven by the solenoid to the right.  Just above the solenoid are a couple of spring contacts and what looks like a disc PTC.  At the top is the bi-stable contact assembly and connector tabs.

    Under the bi-stable contact assembly is another disc PTC and a bi-metalic strip.  Looking at the part again it appears that the cause of failure is probably a poor contact between the bi-metallic strip and the PTC disc.  There is a large discoloured area on the strip where there has clearly been some arcing, but the contact assembly that I cleaned previously is still looking pretty good.