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[USER=”4209″]electrofix[/USER] – thanks, it was indeed wiring. One of the sensor cables was literally snapped at the point where the wires bend as the drum moves about.
Cable spliced and machine is heating and spinning on the test programs, hopefully that’s sorted.
For the benefit of the search. JLWM1437 service/diagnostic mode is the same as AEG 6000/7000/8000/9000. To access, turn off machine at wall. Set dial to Cotton. Turn on machine at wall. Turn on machine with on/off button if it hasn’t come on itself. Touch and hold “Start” and “Reduce Time” for about 3 seconds. Screen will display test (every segment lit). Then rotate dial to desired test program (see YouTube). Any errors will be shown. Power cycle machine twice to exit diagnostic mode.
Last error can also be shown on-screen at any time by touching and holding the same buttons.
In this case it’s showed E62 (overheating) and, on every test program, E71 (faulty NTC) – so I’ll give a new temperature sensor a go first.
Error codes are documented here.
Exploded parts diagram is available via Electrolux here, which gives part numbers for use elsewhere as well.
Thanks. Heater is 31 Ohms and the NTC sensor reads 6k at about 20*C.
Ive been trying to get into diagnostic mode but so far without any luck.
To add. The other thing that’s changed is that if a wash is paused, the door doesn’t unlock. Maybe there is a water level sensor that needs cleaning or replacing?
Both sensors are the same. But what is the problem? My advice would be to measure the resistance across the sensors at the wiring harness and see if you can bring them roughly back to spec with a simple 1/4w resistor cut in to the wiring, either in series or parallel as appropriate.
Find the control board and test the value. You might just need to add a 1p resistor (see my thread on the TFF577)
Unfortunately I can’t upload the image (60KB) as I don’t have enough quota left. But anyway it’s super simple, one resistor cut in to a wire.
Another update for the benefit of the search: the freezer was continuing to frost up. Seems to be a design flaw for frequent use, the defrost cycle is simply too short and the problem compounds. The accessible sensor is the air temperature sensor, whilst the defrost sensor is buried somewhere in the evaporator and inaccessible (as noted in post 2).
However, this is easy to fix for almost no money!
The control PCB is mounted in a section at the top in the back and can be accessed by removing one screw from the plastic cover. Warning: this PCB contains exposed live mains terminals! Unplug the freezer before opening and testing this.
The pinout is as follows and known-good multimeter test values:
[TABLE=”border: 0, cellpadding: 0, cellspacing: 0″]
[TR]
[TD=”width: 87″]Main PCB[/TD]
[TD=”width: 87″]Colour[/TD]
[TD=”width: 136″]Description[/TD]
[TD=”width: 87″]Good Reading (at -18*C)[/TD]
[TD=”width: 87″]Notes[/TD]
[/TR]
[TR]
[TD]KN1[/TD]
[TD]Blue[/TD]
[TD]Supply Neutral[/TD]
[TD] [/TD]
[TD] [/TD]
[/TR]
[TR]
[TD](Mains)[/TD]
[TD]Brown[/TD]
[TD]Supply Live[/TD]
[TD] [/TD]
[TD] [/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]Yellow[/TD]
[TD]Defrost heaters[/TD]
[TD]300R[/TD]
[TD]Test to neutral[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]Black[/TD]
[TD]Compressor/Fan[/TD]
[TD]20R[/TD]
[TD]Test to neutral[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[/TR]
[TR]
[TD]KN2[/TD]
[TD]Blue/White[/TD]
[TD]Dial[/TD]
[TD]30k[/TD]
[TD](position 2)[/TD]
[/TR]
[TR]
[TD](Sensors)[/TD]
[TD]Red[/TD]
[TD]Intake NTC Sensor[/TD]
[TD]30k[/TD]
[TD](-18*C)[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]Black[/TD]
[TD=”colspan: 2″]Dial/Intake Common[/TD]
[TD] [/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]Brown[/TD]
[TD]Defrost NTC Sensor[/TD]
[TD]30k[/TD]
[TD](-18*C)[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD]Yellow[/TD]
[TD]Deftost Common[/TD]
[TD] [/TD]
[TD] [/TD]
[/TR]
[/TABLE]
The defrost heater can be tested by checking resistance across yellow and blue on KN1. Should be about 300R, giving 180W defrost heater power.The defrost stat can be checked, should read about 30k with the freezer at normal -18*C state, by checking across KN2 brown and yellow.
To extend the defrost time, we need to make the control board think the stat is colder than it is. Since it’s a negative coefficient sensor, all we need to do is add a series resistor. I’ve found 4k7 works perfectly (1/4w is fine) – total cost about 1p. This can be added to either brown or yellow on KN2 by cutting one of those wires and adding inline, either soldered and heat-shrinked or other suitable connection method, I used some phone cable jelly crimps for simplicity:
Result is a full defrost and a completely clear evaporator after a week of operation 🙂
Mostly for the benefit of the search:
As suspected, the wiring defrost stat is connected via the PCB behind the temperature control knob. Therefore, the sensor can be tested easily from this point without cutting anything with the aid of a couple of sewing pins (and obviously a multimeter then connected to them, to read the measured resistance across the sensor):
[IMG2=JSON]{“width”:”400″,”height”:”343″,”data-align”:”none”,”data-size”:”full”,”src”:”https://i.postimg.cc/vm1rtGCG/Screenshot-2020-05-07-at-20-24-43.png”}[/IMG2]
The stat *can* be replaced, it’s mounted behind the air inlet at the top and the correct part is 4394720185. There is no cable slack whatsoever. Therefore, the old sensor needs to be cut as close to it as possible, to leave enough cable left to strip back to solder to. The full loop mounting clip also needs to be cut as the replacement sensor is a little larger due to the heat shrink and the flat end of the heat shrink also needs trimming a little:
[IMG2=JSON]{“width”:”400″,”height”:”296″,”data-align”:”none”,”data-size”:”full”,”src”:”https://i.postimg.cc/wT7jv3Nx/Screenshot-2020-05-07-at-20-24-18.png”}[/IMG2]
Having replaced the stat, the defrost is again working but it still doesn’t fully clear the evaporator, especially at one side.
Because of the connection behind the control knob, it seems doable to add a resistor inline to the sensor to bring it back in to spec and/or alter the defrost profile. The PCB does nothing whatsoever except provide a connection to it. I intend to add maybe 4k7 resistor inline and see that helps… the resistance of the sensor reduces as temperature increases, therefore adding some resistance will make the controller think the evaporator is colder than it is, hence extending the defrost cycle (hopefully).
Wow, not a very environmentally friendly design then. Thank you.
Oddly it looks like it has partially defrosted this morning. Maybe the defrost cycle is simply too short and over time the problem compounds.
Next step crash-course on Amtel MCU coding…
