Accuphase has a reputation for building some of the finest gear anywhere, so I was anxious to get this running. However, I was to find that this one was not going to be an easy fix.
On my initial examination, I found that the unit would stay in protection mode. I could see the emmitter resistors on the left channel were cracked. I could also see two other suspect resistors on this board.
On a closer look, I discover that this channel had suffered a catastrophic failure. Once I had the unit apart and started checking components, I found the amout of damage was extensive:
2) Two bad driver transistors
3) Two cracked emitter resistors
4) three (of the four) bad output transistors
I also discovered that the output transistors had been soldered into the sockets on both channels!!! Impossible to remove without destroying the socket/transistor. Some hack had been working on this... Bad Karma. I hate getting units that have had questionable repairs. but I found no further "damage" beyond this.
I found a transistor and resistor substitutions in the protection circuit that were not right, and a substitution in the the rectifier (I remedied these).
I had a brand new set of TO-3 sockets to put into this, so nothing lost here.
