--- In
Homebrew_PCBs@yahoogroups.com, "jmelson2" <elson@...> wrote:
>The fix was to poke the thermocouple into a through hole near
>the middle of the board. This way, the temp controller is sensing
>the ACTUAL board temperature, which apparently is hotter than the
>surrounding air, due to the IR from the heating elements.
Hey, I think you're on to something here! I'm running out of loaded
boards to test on but the one I tried your way came out great --
thanks!!!
I also tried a different empty board ∗with∗ soldermask (unknown
laminate -- it's just a cheapy Futurlec SMT/DIP adapter I wouldn't
mind frying) with the thermocouple in the air and it came out OK
too. Since I varied more than one parameter (soldermask and maybe
laminate), that doesn't prove anything, but it does make me wish I
hadn't ordered a near-lifetime supply of non-soldermask PCBs last
time around.
>I use a ramp and soak thermocouple controller. [...]
Awesome -- thanks for the numbers. (I'll assume all those
degrees/min rates are actually degrees/sec.) They're similar to
mine, but different, so the difference may be critical.
Thank you!!
John Wilson
D Bit