Power drawbar controller - fixed!!

Finally received the remaining components to repair the controller today, namely the SCRs. 

Hacked a small heatsink down to size and assembled the new TO-220 device where the original C230D stud package was fitted, then soldered the TIC106 device in its position. Surely that should fix it?

Refitted the PCBA into the box, connected it up, powered up the machine and......it works again. Good stuff. 

There is some risk due to the component substitution, the lack of any obvious trigger for the original devices to fail and the unknown circuit parameters but there must be a fair chance it is now fixed again. But that will do for now....