On Mon, 13 Jan 2014 12:06:21 -0800 (PST), wrote:

I think the fuser temperature is pretty much determined by its current draw (resistance) and any control is simply on or off.

Ok.

Looks like those are just to kep it from burning the house down.

;-)

Why there are two is a mystery to me. Maybe it consists of two elements in series and if one shorts it would trigger ? Something like that ?

Don't think so in this case as these thermal switches are connected in
series and with no other connections etc, and I can only see the ends
for one heater / lamp?

https://dl.dropboxusercontent.com/u/5772409/Fuser.jpg

I think the two in series is as you say and a safety thing ... and as
only one is marked they are possibly both the same temperature rating.

I have seen n/c thermal switches and assuming 170 marking is the
temperature in Centigrade, I could potentially get a similar
replacement but they are set in holes and facing the fuser roller so
the dimensions could be reasonably critical.

I guess I could just run the printer, turning it on and off as
required and if it seems reliable / useful, treat it to a new fuser in
any case?

Cheers, T i m