Beosound 4 Glass door mechanism

[Madskp]

I have recently aquired a Beosound 4 which have a fault on the glass door mechanism.

What happens when I plug it in is that the glass door is going down, and the motor does not stop so the gears will make a lot of noise.

I have checked that the magnet is in place, and the sensor board (PCB12) is also correctly placed and connected.

However it does not seem to stop the motor that the magnet is beside the magnetic sensor.

I have some thought about it, but want to hear if anyone has experience with this issue before I try to buy spare parts.

Could the magnetic sensor be faulty? The motor does not stop even though I am trying to hold another magnet at the sensor.

I have seen an older thread mentioning a loose belt could have someting to do with timing issues https://archivedforum2.beoworld.org/forums/t/43221.aspx but that problem sounded to be that the glass door could not be keept in open position. Also I guess that the magnetic sensor should stop the motor regardless of how bad the belt is.

Any insights are welcome

[Madskp]

The service manual describes a testing procedure for when the door does not close, or only slides down. In that case it says that if 3.3V is measured on pin 2 in the connector P1 when the door is in the lower position, the PCB with the magnetic switch should be replaced.

I do measure 3.3V even when it is not in that position, so might be an indication that something is wrong.

However the 6V that should also be in that connector, which I would guess is a supply is not there, so maybe something else is also wrong. I tried to measure for the 6V 2 PCB’s down, but still nothing.

I might have to start replacing the magnetic switch, provided I can finde. a replacement, and see what happens then

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