Dear All,
During a gig, there was a power outage. After power was on again, my power mixer had no sound both left & right output. So, I shut it down that night. The next morning, at home I connect everything to check it - no sound still. Then I opened the cabinet of the mixer to see if there was any blown fuse. Looked at the two almost identical PCB - left and right. There was one blown fuse on the left PCB and all components looked good with no burning marks. So, replaced it with a 3A fuse as original. Power it up, the left has output but the right was still dead. Each PCB has its transformer, a floppy disk look alike cable runs from right PCB connecting the left PCB. The difference of the two is that one the right there were a few more components such as 1 x KA7818, 1 x MC7918, 2 x R27 5W. One each board, there are 2 x LM3886TF, a transformer output +35v/-35v, 1 x KBL04, 1 x 1k 250, 2 x 4700uf 63v, 6 x 100nf,1 x 10uf 50v, 2 x 10uf 63v, 1 x 220uf 63v, 2x 3A fuses, and some resistors - 47k, 330ohm, etc.As I am a rookie to electronic circuits,I only know how to replace damaged components. Would some experts give me some rough ideas about what went wrong. The mixer is ETEK Notemix MA400, made in ITALY but discounted more than 10 yrs. No way to find the schematics on the web. Please help!