On Mon, 13 Jan 2014 16:51:27 -0800, Jeff Liebermann
wrote:

On Mon, 13 Jan 2014 23:27:47 +0000, T i m wrote:

No, it was something about cycling the power (that made no difference)
but a Goggle search from that suggested a fuser fault (as one of the
main causes).

Duz this sound familiar?
http://www.fixyourownprinter.com/forums/printer/72871
See 2nd to last comment near bottom of page. That's my favorite fix
of mechanical thermostats.

Hehe! Sfunny, it sounding like there was something 'loose' in one or
both of them but now I know how easy it is to get the fuser out (easy
but fiddly / slightly tedious with all the plugs you need to
disconnect to free the fuser wires (although that might be easier now
g)). I'll try the 'impact reset' test and the good thing is you can
check the result there and then (with yer DMM).

The fuser was indeed cold and (as it turned out) because of what looks
like a thermal switch (or fuse) that had gone o/c. Shorting said
device with some copper wire removed the error message and allowed the
printer to return to a working condition. ;-)

Finding the exact replacement has been a bit of a challenge. This is
the best I can do for now:
http://www.alibaba.com/product-gs/982359539/PT056_Replacement_for_Samsung_4623_1666.html

That's the badger!

which isn't going to be easy to obtain.

I wonder if they would send me a sample? ;-)

The CLX-3175FN manual shows
the part as a 4712-001027 but that's a single thermostat, not a
double.

Yes, I've since spotted that. The problem is though, if they are both
thermal switches and of different temperatures (the second / higher to
be used more as a failsafe in case the first / normal switch sailed
unsafe) then we don't know which one on mine is still functional?

Incidentally, on the exploded view of the fuser, there's an
thermistor-NTC which is what probably controls the temperature.

Yes, I think I offered / suggested such elsewhere (but didn't know if
it was just to provide feedback to the controller board to say 'Warmed
up'?

As what is probably an aside I'm also seeing a horizontal band across
the page. It could be off the OPC drum. I'll have to measure the
circumference but it looks about right.

If the fuser wasn't getting hot, but the mechanism was still moving,
then you could have a nice pile of toner piled up in or under the
fuser. Remove and clean.

Whilst I didn't check that (in my euphoria re finding the 'fault' and
the potential of checking it again), I'm not sure the print error is
of the right interval for the circumference of the fuser rollers. I
see a horizontal line / mark at about 2" down a sheet of A4 and again
at about the same from the bottom. It may be fading with use.

Note: I don't fix or like Samsung printers.

I've not experienced them till now (normally HPLJ here and still have
a trusty P2015dn on our LAN) and so this is the first one I've looked
at. Hundreds of years ago I worked for Kodak on their microfiche/film
cheque processing machines so I have some experience with this sort of
thing. In comparison though, there was much more 'metal' in the Kodak
stuff. ;-)

Cheers and thanks again for all your help.

T i m