Under the label, on either side of the digital readout, there are holes in the plastic. Left center, the small hole has the fan adjust. Only a little change to the fan speeds, really.
On the right, a larger hole has another trimpot. Not really sure what this is supposed to be, though it SEEMED to affect the heat. Perhaps a really fine adjust to the trigger-off or max temp. Didn’t help. What did help was a program Openroast at github. This would turn the heat on and off as set by the program.
After two tries, best dark roast (my goal) ever.
My sr700 will live a little longer.