shiny new temperature probe arrived today 
doesn't work 
took it to pieces (what else! )
found the problem
the two wires are insulated with what looks like glass insulation
then slipped inside a stainless steel "knitted" (thank you Mrs Noah) outer jacket
trouble is at the business end the trimming was awful
with strands of wire touching the probe
and shorting it out intermittently
so - trimmed it back - much easier said than done stainless steel is tough!
wrapped the end of the metal in heat shrink - just to hold it while I re-assembled
temperature readings now rock steady
but
as the probe is inside a metal sleeve, there does seem to be some inertia in the measurement now
the graph below shows the problem
- (apparent) delay in getting started
- overshoot at the intermediate temperature points
a naked thermocouple is much more responsive
(see the original curve posted earlier)
I may well add PID processing - which should stop the overshoot
next decision after that's all working
oh and for amusement here's a picture of the first probe
not completely heat proof methinks!
added link to probe
