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Topics - Melv1

#1
The Newcomer's Forum / HH MA150 blowing mains fuses
September 30, 2017, 08:07:49 AM
Hello everyone, this is my first post on here. Sorry for it being long winded, but I want to try to give you as much info as poss.
  I would appreciate some help/guidance for my HH MA 150. The problem is, it blows both fuses instantly. I have checked the output transistors, they are fine, and I even disconnected them from the main board in case they were shorting to the chassis some how, but fuses still blown. I am confident filter caps are good as I disconnected the power leads, (the wires from the caps to the main board) and this time the fuses didn't blow. So I assume everything upto there is fine. I then checked all components on the main board, There were many problems, most transistors were faulty,I replaced Q2,3,4,5,6,7 (  these were all faulty when checked out of board too), also many resistors were out of spec and there had been a burn out around  R 22,24,28, one of those 3 was totally burnt black but I can't remember which one. I replaced R4,13,19,20,22,24,26,27,28. I was confident the problem would now be solved, but no, the fuses still blown. I also checked all diodes and they are fine. Any help would be very much appreciated as I am now stumped.