Thank you Rich for identifying U2. Now it is clear that PIC can control buck converter voltage and PIC is connected to control board - two pins from PIC (pin #2 and #4) go to controller board (TX and RST2).
My board has currently malfunctioning buck converter, it has only 8.7V across the chain which I belive is the lowest voltage set without digital pot, so my best guess is that we should be able to set PIC digital pot to control voltage from about 9V and voltage can be set even more that 10.59V.
Have you identified where on the controller board the PIC connections go to? A thing worth trying is to read the code from the PIC, manufacturers do not always remember to code protect. If you have the means to do this please give it a go, if not PM me and I will send you a PicKit2 which I have several of left over from a previous project.
AS this is getting a bit detailed I wonder if you should start a separate thread for this stage of the project?
Rich
