[ianB22]

Re: AEG Lavamat 74530W stops during the program without erro

Just to add a further candidate solution for control board fixes after random cycle stops.

We have an AEG Lavamat 1250 (914 002 4259 00) which developed a increasingly frequent habit of randomly stopping mid cycle. Washing was always ok, but often quitting in rinse / early in spin… Until it always stopped.. with much like symptoms others have seen here.

Error code 52 initially but through various testing, also 33, 11, 51 appeared. I discovered the control board can also seem to “lock-up” showing no error code. From previous knowledge of embedded systems, this suggested to me the micro-controller may have an unstable power supply. I did waste lots of time on other checks before focussing on the control board though.

So, in addition to the black dust (agree with earlier post it’s probably ferrous motor brush dust) around the transformer area of the PCB and big resistor, I discovered multiple microscopically fractured solder joints on many of the power related components. All the power stuff is at the control knob end of the PCB / bigger components – that is, not the little (SMT) dots and chips. Note that these radial solder joint fractures are only visible with a LOT of magnification under strong light.

Having checked all the non-SMT / power components joints and re-soldered everything that was looking fractured (probably 10 joints), the machine works 100{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} reliably again. I hope this helps others save the cost of an expensive control board. This solution should be under an hour’s work and costs zero (if you have an electronics soldering iron of course).

My theory is that the bigger components are heavier than the tiny SMT ones and the vibration of spin fatigues the joints over a few years. This is very likely to make the power supply to the “brains’ progressively unstable and so increasingly likely to lockup the micro-controller (that is, the whole control board / wash cycle). It could also explain why gentle motion of washing is not enough to destabilise the “brains” on-board power but rinse and spin vibration will fairly quickly.

A final suggestion / tip re the electrolytic capacitors (little can shaped items) which were mentioned earlier as candidate causes. These are very often the first items to fail in ALL old power supplies as the innards “dry out”. If the very top of the can bows upward, like there is pressure inside, it a sure sign that that capacitor is dead and must be replaced.

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