Hi Alan,
Thanks for the reply! I am not having a problem but was trying to get a schematic of the circuit for someone who wanted to know what kind of wave form it produces and how it is achieved, possibly with triacs? More of an academic exercise than an issue, but I would like to know what's going on if I had a problem. I know you have to unsolder the pot to get to the circuit board. I cut away part of the heat sink to get to the whistle switch contacts, but that was for another project where I wanted a second whistle switch.
So I just needed a printed schematic, if it was ever available to the public.
Thanks!
Take care, Joe.
P.S. The model number I added to the original post after it was up for a while, # 6-12885.