All:
I just got a down-and-out NAD 705 receiver. The origanal owner had given up.
I'm new to this, thanks in advance for the advice.... I have to replace the lamps, that was easy enough to find. The protection circuit seems to work, unit powers up. I hear the output relays working. Once I figured out the input selector w/o help of the backlight lamps, I had a working receiver.
Problem: One channel is quieter than the other. I tested between A and B outputs, same result. Duh. I tested AUX and CD, same result. Now, I crossed the pre-outs and in and I got the quiet channel to switch sides. Hmmmm. That tells me I am looking for something messed up in the pre-amp. ????. What device in the preamp would cause all inputs to be quiet on one side? I can't see anything burned up or broken off hand. Not that I would expect, it works but has a gain screwed up or something. Any recommendations?
Thanks again. I AM looking for a good read on the subject....
Also, DC output on the amp channels read 20 mV and 40 mV. I have not tested putting another preamp OUT into the IN of the power amp section. I guess that would verify function of the power amps.
The various preamp level adjustments seem to be clean and functional. Moving them did not cause any level variations or indicate a problem.
jocko
I just got a down-and-out NAD 705 receiver. The origanal owner had given up.
I'm new to this, thanks in advance for the advice.... I have to replace the lamps, that was easy enough to find. The protection circuit seems to work, unit powers up. I hear the output relays working. Once I figured out the input selector w/o help of the backlight lamps, I had a working receiver.
Problem: One channel is quieter than the other. I tested between A and B outputs, same result. Duh. I tested AUX and CD, same result. Now, I crossed the pre-outs and in and I got the quiet channel to switch sides. Hmmmm. That tells me I am looking for something messed up in the pre-amp. ????. What device in the preamp would cause all inputs to be quiet on one side? I can't see anything burned up or broken off hand. Not that I would expect, it works but has a gain screwed up or something. Any recommendations?
Thanks again. I AM looking for a good read on the subject....
Also, DC output on the amp channels read 20 mV and 40 mV. I have not tested putting another preamp OUT into the IN of the power amp section. I guess that would verify function of the power amps.
The various preamp level adjustments seem to be clean and functional. Moving them did not cause any level variations or indicate a problem.
jocko
jocko_nc said:I have not tested putting another preamp OUT into the IN of the power amp section. I guess that would verify function of the power amps.
Just take away bridge pins from pre-power plugs and connect phono cables in cross to verify if it's pre or powerstage level mismatch.
Hi claudiomas,
I have the equipment, but no schematic for this one or unit. I do remember the tough troubleshooting on a similar model.
-Chris
Who?schematic diagrams??? have you a af generator and oscilloscope?
I have the equipment, but no schematic for this one or unit. I do remember the tough troubleshooting on a similar model.
-Chris
4fun said:
Just take away bridge pins from pre-power plugs and connect phono cables in cross to verify if it's pre or powerstage level mismatch.
Sorry for my post, as i have not obviously not read your initial post carefully enough
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