UPDATE
Okay, got some news from my tech guy about sx-737 repair
Apparently like @ecluser said - one of the output transistors was bad (Q14 2sb541)
It tested good with multimeter and transistor tester, but in circuit it had 2.2k resistance between B-E. This is what I was told. I had no replacements to swap, so I was chasing my tail changing everything else.
Protection circuit is fixed - Q3 2sc945 changed into two resistors - now it works like a charm.
Also tuner board needed a transistor replacement due to former 13V line fail (toasted transformer) Q3 2sc535 went bad.
Fixed unit is coming back soon, so I can work on externals. Already finished a whole new set of knobs 1:1 with the original ones. New glass is already cut, waiting for uv print
New neglected unit is waiting. Bought sx-750 for cheap. Working, just some balance issues (No lows and poor sound when set to 0, sound improves when set to L or R) ripped veneer and sticky dust.
Okay, got some news from my tech guy about sx-737 repair
Apparently like @ecluser said - one of the output transistors was bad (Q14 2sb541)
It tested good with multimeter and transistor tester, but in circuit it had 2.2k resistance between B-E. This is what I was told. I had no replacements to swap, so I was chasing my tail changing everything else.
Protection circuit is fixed - Q3 2sc945 changed into two resistors - now it works like a charm.
Also tuner board needed a transistor replacement due to former 13V line fail (toasted transformer) Q3 2sc535 went bad.
Fixed unit is coming back soon, so I can work on externals. Already finished a whole new set of knobs 1:1 with the original ones. New glass is already cut, waiting for uv print
New neglected unit is waiting. Bought sx-750 for cheap. Working, just some balance issues (No lows and poor sound when set to 0, sound improves when set to L or R) ripped veneer and sticky dust.
