Yes, thanks dave that 3020=3020A, but the 3020 does not have the schematic for the phono stage with MC. Do you agree that the schematics of the phono stage (MM & MC) of 3020A is exactly the same as the one of 3020B??? Apologize if I interrupt you again.
NAD 3020 parts
Planet10 or anyone,
where can i find NAD3020 parts? I looked a bit on the net but nothng as yet.
of particular interest is the a replacement of the volume control "rheostat ? " which caused pops when turned and pressed towards zero volume, and has hum during the first few minutes; also the volume display LEDs is not working ie only the first LED is lit at mid volume level.
referring to pops, these also occurred when i tap on the power transformer or at times on the wires from the switched and unswitched sockets..and at time even on the chasis in general. for the chasis, when i tapped to cause those pops,it might be transfered from the volume controls parts being vibrated.[help=]%[/help]
appreciates any lead or advise.
Calvin, San francisco bay area, california
Planet10 or anyone,
where can i find NAD3020 parts? I looked a bit on the net but nothng as yet.
of particular interest is the a replacement of the volume control "rheostat ? " which caused pops when turned and pressed towards zero volume, and has hum during the first few minutes; also the volume display LEDs is not working ie only the first LED is lit at mid volume level.
referring to pops, these also occurred when i tap on the power transformer or at times on the wires from the switched and unswitched sockets..and at time even on the chasis in general. for the chasis, when i tapped to cause those pops,it might be transfered from the volume controls parts being vibrated.[help=]%[/help]
appreciates any lead or advise.
Calvin, San francisco bay area, california
The volume control can be replaced with just a regular 20K dual log pot, at the cost of the Loudness function.
Tapping causing pops is probably a dry solder joint somewhere. Rework them all.
Hum while warming up is most likely capacitors reaching the end of their life.
Tapping causing pops is probably a dry solder joint somewhere. Rework them all.
Hum while warming up is most likely capacitors reaching the end of their life.
Jaycee,
thanks for the reply.
So, one cannot find exact parts replacement??? I hate to lose the loudness function,though.
Particularly if the problems with the LED volume display might be the ic chip, although i not sure what causes the malfunctioning. Maybe if it is ,then it might be standard chip. I supposed i can dig deeper even though my electronic know-how is limited. although desoldering and soldering for replacement ie switch parts is easy enough.
Cal
thanks for the reply.
So, one cannot find exact parts replacement??? I hate to lose the loudness function,though.
Particularly if the problems with the LED volume display might be the ic chip, although i not sure what causes the malfunctioning. Maybe if it is ,then it might be standard chip. I supposed i can dig deeper even though my electronic know-how is limited. although desoldering and soldering for replacement ie switch parts is easy enough.
Cal
Funny, I just started pulling apart my NAD 3020 first generation yesterday. Haven't decided whether to try and resurrect it or just replace the internals with more modern equivalents (some MyRef LM3886 boards for the power amp section, etc.).
I'm not sure about the later models, but the LED meter on the first gen is a simple circuit taken straight from the LB1405 data sheet "vu-meter" (attached). The board takes a low voltage line directly from the transformer and rectifies it with a diode and cap for power. Ground and signal are provided from the main board.
If all you are seeing is the single LED displayed, I would look closely at the small adjustment pot or the first input cap (electrolytic) as the prime suspects.
Failing that, it's a pretty standard circuit, so replacement with a more current chip is an option. The LEDs are on standard perfboard hole spacings, which helps a lot here.
I'm not sure about the later models, but the LED meter on the first gen is a simple circuit taken straight from the LB1405 data sheet "vu-meter" (attached). The board takes a low voltage line directly from the transformer and rectifies it with a diode and cap for power. Ground and signal are provided from the main board.
If all you are seeing is the single LED displayed, I would look closely at the small adjustment pot or the first input cap (electrolytic) as the prime suspects.
Failing that, it's a pretty standard circuit, so replacement with a more current chip is an option. The LEDs are on standard perfboard hole spacings, which helps a lot here.
Attachments
Hello!
Thanks Planet10 for uploading the link of service manual NAD 3020 .. It is very comprehensive! 🙂
I see I have +32 volts and -32 volts instead of +28 volts and -28 volts in power supply .....😱 and turn the amplifier speakers move too abruptly ....
Source capacitors 4 x 2200 uF 35 V are correct because apparently loaded and unloaded and are not shorted, but may have little capacity and idle ripple?
Maybe I should adjust the offset?
From already thank you if you can help me.
It's really a great amp, bought it new many years ago now, and it's the first time presents a problem.
Regards
Rolo
Thanks Planet10 for uploading the link of service manual NAD 3020 .. It is very comprehensive! 🙂
I see I have +32 volts and -32 volts instead of +28 volts and -28 volts in power supply .....😱 and turn the amplifier speakers move too abruptly ....
Source capacitors 4 x 2200 uF 35 V are correct because apparently loaded and unloaded and are not shorted, but may have little capacity and idle ripple?
Maybe I should adjust the offset?
From already thank you if you can help me.
It's really a great amp, bought it new many years ago now, and it's the first time presents a problem.
Regards
Rolo
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