Marantz 300DC schematic

[Pery]

Please, could anyone send me a schematic for the Marantz 300DC ?

Thank you !

 

[jblmar]

What's wrong with it?

Ron

 

[Pery]

The right channel main amp in the Marantz 300DC has suffered with the heat and it is with a bad distortion. I have many schematic diagrams and service manuals but not for the 300DC. Marantz SM7 power amplifier has the same circuit board P700. I found many information in the site HiFiEngime.com but not for the 300DC. Thank you for any help!

 

[jblmar]

Does it distort as the amp warms up, or as soon as you power up?

Ron

 

[Pery]

Marantz 300 DC power supply.

Hi Ron,

I am studying the schematic of the Marantz 300DC...
It has dual secondary power supply for -70V ,0,+70V.

I didn't understand why they put -70V connected to the ground in the L ch
power supply output.

I tried to attach the power supply drawing.

Thank,
Pery

 

[jblmar]

Pery,
The +/- 70 volts is produced in the power supply. The voltage isn't connected to ground. That would destroy the components.

Ron

 

[Pery]

HI Ron,

Is me again about my Marantz 300DC P700 R(ch): I can't find here in Rio de Janeiro a repair shop or technician able to repair the pcb or find the spare parts. There will be transistors to replace...and more.

Do you think is possible to buy a new or 2nd hand P700 in US ?

Or it is possible to you to receive my P700 and repair it ?



Thanks again for any help .

Pery

 

[jblmar]

Pery, you have a PM.

Ron

 

[Honest_Ron]

Real old thread, but I just received my old 300 DC (purchased new) from my brother with some distortion in the right channel. Recapped all the electrolytics and still have distortion. Manuals I find online don't show all of the part details on the diodes. Wanted to replace transistors and diodes next on the P700.

Any details on P700 or comments would be greatly appreciated.