Add flyback Diodes to Marantz 4300/4400

[goldswimmerb]

Hey, I would like to add flyback diodes to my Marantz 4300s amp boards, there's a few pics around showing the 4400 having them, but I'm not able to discern how they're wired up.

Anyone either know how they are, or would be willing to post pictures of the 4400s flyback diodes?

For reference this is the best pic I have, and I cannot tell where the leads are going towards the center of the board.



Thanks guys!

 

[catrafter]

The green end is the banded end or cathode. I use 1N4007, but 1N4004 should be fine.
The diodes are soldered to the large resistor leads. Blue dots
Please excuse the crude drawing.
BTW the red circles indicate the 2SC458 'bias' transistors hiding under the heat sink

The addition of protection diodes to a power amp can usually be sussed out by examining the schematic.
Tom

 

[goldswimmerb]

The green end is the banded end or cathode. I use 1N4007, but 1N4004 should be fine.
The diodes are soldered to the large resistor leads. Blue dots
Please excuse the crude drawing.
BTW the red circles indicate the 2SC458 'bias' transistors hiding under the heat sink

The addition of protection diodes to a power amp can usually be sussed out by examining the schematic.
Tom
View attachment 1673112

So it's just across the resistors? I got thrown off because it looked like there was a wire or something going to pins 21 and 23.