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Marantz SR8000 DC Offset & Idle Current Adjustment

CoreyS

CoreyS

New Member
I just received a Marantz SR8000. It works fine. Sounds good. I downloaded the service manual because I wanted to set the idle current adjustments and DC offset. I cannot find any info on these topics. I do see two adjustable potentiometers on the amp board. If anyone has worked on this and can offer some help, I would greatly appreciate it.
 
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CoreyS said:
idle current adjustments and DC offset
Click to expand...

No idle current adjustment for the encapsulated output stages.

The two pots on the driver board (the board with one 15-pin "voltage amp" chip, apparently designated PN00) are for DC offset. Since the receiver is working, you can adjust these by metering the DC voltage at the speaker terminals (with speaker switch set to on, and volume control all the way down). You'll have to guess which pot is right and left (or else spend more time looking at the manual than I did) - it will be obvious once you start tweaking the pot. You are aiming for, ideally, zero volts DC. Be patient, as the voltage will probably make large swings for a small tweak, and then settle in a few seconds. Don't obsess about getting to exactly zero - less than, say, 20mV (either + or -) would be very good.
 
By the way, there is a Marantz forum on AK. I don't know if the regulars there have an animus toward "chip amps", but there doesn't seem to be much discussion of this series.
 
i am guessing that what the op is seeing are adjustments for power meters as there are no VRs shown in the power amp schematic.(meaning no amp adjustments)
 
painttoad said:
no VRs shown in the power amp schematic
Click to expand...

I'm fingering RN09 and RM10 on the PN00 driver board. It's true there are no VRs on the P700 output board.

Or maybe we're looking at different schematics? It doesn't help that Marantz recycled "SR8000" as a model designation! I'm assuming the OP has the pre-AVR-era model.

Cheers
 
chazix said:
I'm fingering RN09 and RM10 on the PN00 driver board. It's true there are no VRs on the P700 output board.

Or maybe we're looking at different schematics? It doesn't help that Marantz recycled "SR8000" as a model designation! I'm assuming the OP has the pre-AVR-era model.

Cheers
Click to expand...


ding ding ding.

you win!

i did not catch that board before and the schematic does label them as dc offset.

rn10 for right channel, 09 for left.
 
Thx chazix! You were right. I adjusted the DC offset and I’m going to leave it at that. I am a big fan of Marantz especially the 2270. The newer ones with the chips are obviously not as easy to repair. But this receiver sounds pretty sweet. Very beefy.
 
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