tonebells, here is the update from my tech, I couldn't get it going. The amp board you sent had good outputs, but the board itself caused a failure when it was installed and I could not trace the problem so I sent it to the Marantz guy I used.
Here’s an update on the 4300. The right rear channel had 30 volts offset. On the right channel driver board, there are 4 transistors, h707,8,9,10, 2sc627, small round metal cans with heat sinks on them. A quick check with my analog meter showed that they were not normal, although with a digital meter in the diode test mode, they appeared ok. When I removed them, one leg of one of them fell off. I discovered that when they attached the heat sinks to the transistors, they used a glue, and on 3 of them, the glue had gotten onto the transistor leads, corroding them. I checked the left bank but, the glue was not present on the leads. I don’t like the way they test, so I have ordered some replacements. I used NTE 154’s for the right channel (bought all the local guy had) and have ordered 2n3440’s for the left. The Right front channel dc balance would not zero, swapping the differential pair solved that. The rear left channel indeed had no pre-out. Finally determined that the signal was getting lost on the pe01 board. Leaky transistor he14. Thought I had her all done, but discovered that 3 of the 4 channels are noisy (white noise and rumbling at zero volume, tone controls do affect). I had hoped it would turn out to be noisy transistors on the pe01 board, but it is not. I believe it is coming from the pd01 board, which is a bear to get to. Have to remove the front panel and pull the tone control/board assy. to get to it.
Thanks Rich
