Bad Channel...
The right channel was dead. This is usually an easy fix. You think... "ah, it's just a bad resistor or
transistor".
Well... this channel was a mess. I think something must have gotten slopped down into the unit and
shorted out a bunch of stuff. I pulled the transistors off the board one at a time, and tested each. I
found three bad transistors. Then I started with the resistors... again, three bad resistors. Lucky for
me, I had direct replacements on hand. I tested the main output trannies on this channel and all
seem good to go...
The right channel was dead. This is usually an easy fix. You think... "ah, it's just a bad resistor or
transistor".
Well... this channel was a mess. I think something must have gotten slopped down into the unit and
shorted out a bunch of stuff. I pulled the transistors off the board one at a time, and tested each. I
found three bad transistors. Then I started with the resistors... again, three bad resistors. Lucky for
me, I had direct replacements on hand. I tested the main output trannies on this channel and all
seem good to go...
I got the strangest pattern... one half of the form was randomly clipping and jumping about. So I
took the channel out of the unit and went over it again, but did not find anything. I decided that
one of the main output trannies must be screwy. I had a matched set of Toshiba outputs. These are
a direct part number replacements (2SD427 - labeled "Toshiba"... guess who made the Original
"Marantz" transistors... ). So I dropped them in (both channels... I would not break up a matched
set). This fixed the problem. The unit is producing 102wpc... too cool !!!
took the channel out of the unit and went over it again, but did not find anything. I decided that
one of the main output trannies must be screwy. I had a matched set of Toshiba outputs. These are
a direct part number replacements (2SD427 - labeled "Toshiba"... guess who made the Original
"Marantz" transistors... ). So I dropped them in (both channels... I would not break up a matched
set). This fixed the problem. The unit is producing 102wpc... too cool !!!
Right and Left
channels
displayed with
inverted left
channel so you
can see them
both.
channels
displayed with
inverted left
channel so you
can see them
both.
