Microwave oven timer

I have a microwave oven with a busted timer. It works fine in all other ways, it's just that the rotary time control doesn't un-rotate, so the m/wave runs continuously. It's an extremely cheap no-name one from Sainsers (*). (Who replaced it, even though it was outside of warranty, so we have the broken one spare, now).
Is it even worth trying to repair? IIRC, it only cost GBP24. Can you buy the timers? A Google search is unsatisfactory. It's presently on the pile of stuff to go to Emmaus (http://www.emmaus.org.uk /), but its brokenness offends me...
(* Purchased for my 90 y/o MIL. We weren't sure she was going to like it, so got her a super-cheap one.)

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I can't imagine finding one and getting it delivered for much less than £24. I suspect your only hope would be if you can repair the broken timer.
There are issues with opening up microwaves -- very high voltage, needing to get the case screwed back together acuurately, etc. If you aren't familiar with these, it's probably best not to attempt to repair it yourself.

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That was kind-of my feeling.
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Well, I've worked on high power HF linear amplifiers (well, ~2kW ones) so the high voltages, etc., aren't too scary.

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There's a 30 minute mechanical run-back timer on rswww for £13.15
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I've got a variable time delay relay, delay varied by a knob, new and surplus to requirements (pre ROHS) you can have F.O.C. if you like.
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On Top Band ?? Ahhh, those were the days.
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:-)
Derek

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That's very kind, but I think I'll give it to Emmaus as it is. I don't actually *need* another m/wave.
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Tsk. What's the legal maximum output on Top Band these days?

writes:
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It may be worth spraying the shaft of the timer with WD40. It is possibly a mechanical problem due to friction. It might even be the knob that has got distorted.

Andrew Gabriel wrote:
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Its OK as long as it is back together before you switch it on with all the seals in place ;-)

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Not worth it!
http://direct.tesco.com/q/R.200-6497.aspx

Huge wrote:
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You could just use a separate "pinger" timer, and try to remember not to leave the unattended and switched on for a couple of hours. In other words, use it in the shed.
The glass turntable makes an attractive fruit-plate, the motor can be reused in a revolving display or mirror ball, and you can get (several) mini-ITX boards inside the cavity to make a kitchen server/PC. http://www.mini-itx.com/projects/itxtv /
Owain