Help – faulty Hotpoint HD62X cooker hood

[GesNielsen]

When I press the ‘on’ button the motor starts but only runs for 2-3 seconds and then cuts out. If I hold the button in the process repeats – motor runs up then cuts out, runs up then cuts out etc etc
Another interesting bit – if I turn the lights on and then press to turn the motor on the lights switch off!

[electrofix]

that sounds like a control panel fault

looks like its over £100 to buy it

you could look inside it as its common for capacitors to blow on panels

google bulging capacitor

Dave

[GesNielsen]

Hiya
Thanks Dave. The components all look OK.There’s only 1 large electrolytic and I checked it offline with a meter on resistance and it seems to be charging normally. My plan now is to try running over the joints to check for dry joints. I was gobsmacked at how much replacement boards are, but if that’s the problem then I suppose I don’t have much choice – other than to buy a new cooker hood!
Thanks again
Ges NIelsen

[tubafan]

Have you checked that the fan is nice and free running as I’m wondering if it’s detecting an overload of some sort? As you say the price of the new board is crazy and think I’d be looking at a new hood as it looks like you can get an equivalent for about £160 if you shop around..

[GesNielsen]

I wondered about overload as well, but the motor seems to be quite free running; or at least, with the power off it spins quite nicely by hand. Also, with the ‘on’ button held in it does spin slighty faster on the 2nd and 3rd on/off ‘cycle’, so it seems to spin OK. The other alternative I wondered about was if there might be an error with the motor and the circuit was detecting an overcurrent, but I haven’t any idea if it has any overcurrent detection (apart from blowing a fuse).
And I agree about buying a new one – I’d far rather fix it rather than just create yet more waste, but when it’s a similar cost to buy a new one as fix something that’s over 10 years old it becomes far more difficult to justify.
Oh, the other thing is the weird bit that if I turn the lights on first and then press ‘on’, the lights go out (but will restart if I press the ‘lights’ button again). There didn’t seem an obvious way for the two circuits to interract – the mains live to the motor and lights transformer seems to be filtered on the circuit board but not switched, and the ‘neutral’ for each seems to be switched via separate outputs from the microcontroller. I’ve run a soldering iron over all the joints, so I don’t think there are any dry joints. I also tried taking out the semiconductor leading to the lighting neutral output (no idea what it is as the number’s illegible – perhaps another TRIAC?) but the motor still didn’t work properly. Hmmm, I think it’s probably knackered!
And thanks again for your help, it really helps having someone who knows how they work!
My plan today is to disconnect it and connect a little 5V supply to the microcontroller itself to see if that’ll tell me anything more, but frankly I’m completely in the dark. And you seem to be saying that it’s either replace the board or preferably get a new cooker hood, so perhaps it’s just time for me to admit defeat and get my wallet out!

[electrofix]

thats got all the makings of a power supply fault on the board

there is enough power to hold the lights on but as soon as you want more power it crashes

Dave

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