Sencore SG165 power supply board error


2012-12-10 9:37 pm
I purchased this unit some months ago and finally got around to checking it out. It looked good and all functions checked out. I dug into it and cleaned up the pots and switches and decided to replace all electrolytics in the power supply. Then to my surprise after putting it all back together nothing worked. On checking the power supply I had about 10.5 volts on the pos. side and a minus seven for the negative side. Same readings after unplugging the power to the main box. Checking over the power supply I could find nothing wrong. I had replaced all six caps correctly according the the silk screen legend on the board. Then in frustration I checked the old 2.2 mfd caps in the regulator circuit and found the neg. leads bent over for vertical mounting and the pos. leads cut short where the caps sat upright on the board. My new caps were just the opposite but I had followed the markings on the board. The markings do not agree with the schematic. Reversing the 2.2 caps corrected the problem and all was OK. The power supply board in my unit is numbered 43A47. Hope this may help someone else out.