"NT" wrote in message
...
On Sep 15, 7:59 pm, "Tim Walters" wrote:
Hello. My parents have got an ancient Smiths timer which controls some
outside lights. At the moment, no matter how the timer is programmed, the
lights are on all the time, unless the timer is actually switched off. Dad
used to fiddle with it and, miraculously, it did what he wanted. Now, for
some reason, it won´t.

The timer has an override button on the left. Then there's a row on three
buttons (hours, minutes, and set). Then there´s a vertical slider with S
at
the top and N at the bottom. There's a window above the buttons where the
time appears.

Thanks for any suggestions.


crikey, dont give us anything to work on. Get a multimeter, open the
timer and see whats going on.


Ok. There are three screw-type contacts (like the ones inside a standard
3-pin plug). One is labelled COM, the other teo are labelled L1 and L2.
(There´s actually a mirror-image arrangement on the other side of the timer
but these are all dead.) There are only two wires - black and red. The red
goes into the COM and the black into L1. After taking the back off, I could
see three small cylinders connected to the contacts. A black burn mark
showed that something had burnt out. I took the thing down to a local
electrical supplies wholesale shop and showed it to a very competent guy
there. Getting a new timer wasn't an option because the ones that work with
just 2 wires are limited to four hours. Getting a new programmable timer
would mean re-wiring the system.

The guy suggested I try putting the black wire into L2, and maybe I would
have to reverse program the thing (on = off and vice versa). I tried this
but it didn't work. The lights stay on when the timer itself is switched on.
The difficulty is I'm not completely sure how to program the thing in the
first place. For instance, what do N and S mean on the slider? What exactly
is the purpose of the Override button?

Can anyone suggest anything?