Extract fan, electronics help.

Similar fault symptoms of the failed fan, with identical electronics, that BigClive fixed. Failed electrolytic capacitor. Two capacitors sit very close to a resistor dissipating 1+W

Is it a brushed fan? Could just be its a bit worn out and slightly shorting out as it runs and this usually trashes the triac, so a good idea to be a bit wary on just replacing that unless you have a bag full. Brian

Ooo, that's finished is it? I think I remember some here being interest to see that (before / after)?

Does it work, have you used it etc?

Cheers, T i m

yes

So when you have dumped, leave the room and turn out the light the fan will still drive the poo pong into your neighbours open window...

The Natural Philosopher pretended :

Why are you answering a question I was aiming at the OP.

If the permanent live is not remaining live, then the timer cannot operate to supply the fan.

That high power 22k resistor could be dropping over 2.5W, so that could easily be the case on this one as well.

Yes it is finished....

Before:

Fan has a mind of its own, after re installing last night so at least I had a working fan, this morning it started working ok and ALSO the timer, later today the timer stops working and now it is again slow to start. I will leave for a couple of days and then go back to Clives video.

Excellent. Good job. ;-)

Enjoy.

Yeah, I remember that shot now ... it looking pretty sorry for itself.

Thanks for sharing.

Cheers, T i m

As a temporary fix you could just connect switched line and neutral direct to the fan motor leaving the timer totally disconnected. This would at least give you a fan that you could turn on and off manually.

If it still keeps being slow to start then you know you have a problem with the motor and if it runs fine then you know the timer needs fixing.

Over tha last day or so it sometimes is slow to start other times it starts immediately and at other times the over run timer works when light switched off.

So the timer circuit is at some staged of being shagged (technical description!)

You could simply take the electronics out of circuit. Wire the switched live to leads directly feeding the motor, and have a working fan with no run on.

Or you could fix the electronics. If you want a stab in the dark fix, I would go with swapping out those two electrolytic caps.

You can also buy the whole run on timer module as a spare if you prefer. E.g:

Plan:

ok, No.2 is a 47 uF (micro farad) 16V working cap. That is likely just used for smoothing the power supply to the timer chip. The values are not that critical - you can use both higher capacitance and higher working voltage if you already have something to hand. It's worth going for one with a 105 deg C temperature rating since it's close to the hot resistor.

N0.1 I can't see the side with the specs on it - however I would guess a few hundred uF - so perhaps 330uF or similar based on the size.

On that the capacitance is slightly more critical (since it will affect the range of run on times you can get out of the timer chip). So try to go for a similar capacitance. (the working voltage needs to be the same or higher). Again, go for the 105 deg C version.

Note both are polarised caps - so make a note of the -ve lead positions when swapping them. (looks like the -ve leads are facing outwards from the pic - i.e. toward the chip on 1 and toward the pot on 2)

Thanks John, I should be able to get the specs this end on no1.

Circuit

I have ordered capacitors so will update when I receive them and hopefully not frazzled the board with my soldering.

Ah, well spotted.

Yup that circuit is slightly cruder than I expected (and I was not expecting much)! Still I suppose a 4000 series CMOS logic chip is peanuts, and price is the key driver on these kinds of things.

Yup - and a decent branded cap aught to last a bit better.

UPDATE: Capacitors replaced and fan working normally with timer. Thanks all (and BigClive :-) for the input and help in sorting it