There are two printed ciruit boards for the 77-285. You must first determine which you have. Circuit board "A" This board can be identified because D18 has been cut.To restore full power simply resolder D18 or replace it. Circuit board "B" On the "B" circuit board D18 is intact (has not been cut out).To restore full power, locate D18 and trace the etch. Put a solder bridge between the open pads.