wrote:

Ray L. Volts wrote:
wrote in message
oups.com...

The part is a mystery though. My guess is that it is a thermal fuse or
Transorb (not sure whether these work with AC at all). Markings on it
are 7C241 49P (with the symbol 'SA' in a circle). I have tried all the
obvious combinations (googled endlessly), but no luck.

http://en.wikipedia.org/wiki/Varistor

and much more than u wanted to know from one manu:
http://www.epcos.com/inf/70/db/var_01/00190041.pdf

The 'sa in a circle' is actually the safety designation "CSA" (Canadian
Standards Association), a certification listing like UL.

Hard to see the left logo leg, but the '7' looks like a triangle to me. It,
along with the other funky E character would be the manufacturer logo and/or
plant markings. I can't be certain about your MOV's rating, but the '241'
suggests it's a 240-volt. The '49p' may be the date code or the transient
energy joule rating (49).

Great, thanks to you both for the help :-)

But of the two which should I use - a Transorb or a Varistor (it looks
to me like they are more-or-less interchangeable)?

Transorb is simply a trade name owned by some company for varistors.

Assuming that I can't find the actual direct replacement, can you
suggest a value for the alternative Transorb or Varistor (the fuse is
rated to 4 Amps and was quick blow by the way).

Well, it's unclear if the varistor was indeed 240V. It shouldn't have blown if it
was. It might be easier to ask who you buy components from. I can point you in the
direction of Farnell but without an account the minimum order is £20 .

Remember, it won't hurt if the varistor's not there right now. It's only needed to
deal with overvoltages.

The fuse look like it was 20x5mm size and you should get one specced at 250V with
a F4A (L) current rating.

Graham