No I haven't.the thing I was getting at is one thyristor circuit worked at an acceptable temperature but when the potentiometer was changed to a different corded one I got a different result in temperature.both the potentiometers were turned down to zero so there's not really any other possibilities as to why two different results from technically the same parts
Do the main pots and the preset ones have identical values on both controllers?
Have you adjusted both the main and the presets to minimum on both controllers?
Is there a fixed resistor in series with either pot on either controller?
The multi-turn preset on the PCB is in parallel with the control pot. Maximum resistance = later firing & minimal output.
The preset limits how high the overall control variation can be.
Soldered the better pot to the board and then turned the preset trimmer down till it started clicking and now the minimum temp when set to zero
is 50'c. That's awesome now this thing works as it should.so the pot was the source of variance.now I know how to get them working how I want.thanks for the help guys.