Hello, Diyaudioers:
I recently bought a nad 3020 on ebay for $120.
But there is some clicking or cracking sound from it when playing,
I doubt it is from the input selector buttons.
There are 4 input selector buttons: aux, tuner, phono, tape.
and there is a loudness button and a audio muter button.
The clicking sound is different from that produced when I push and release the buttons,
very crisp and short, and it is especially obvious when I turn the volumn low to loud.
Normally the clicking sound does not affect the music, but occasionally it will cut the amp off with no power output.
Can you give me some troubleshooting guidelines on it?
Thanks!
I recently bought a nad 3020 on ebay for $120.
But there is some clicking or cracking sound from it when playing,
I doubt it is from the input selector buttons.
There are 4 input selector buttons: aux, tuner, phono, tape.
and there is a loudness button and a audio muter button.
The clicking sound is different from that produced when I push and release the buttons,
very crisp and short, and it is especially obvious when I turn the volumn low to loud.
Normally the clicking sound does not affect the music, but occasionally it will cut the amp off with no power output.
Can you give me some troubleshooting guidelines on it?
Thanks!
islanddancer said:
Not really. Your description is not particularly specific.
You can make sure that it is indeed the preamp section to blame by removing the jumpers at the back and plugging a source with a built in volume control in the power amp section. Once the power amp has been cleared you can try to see if all preamp inputs behave the same way and this will eliminate the source selector. Are both channels equally affected?
It is really amazing how well the value of an entry level amp has kept up with inflation. I remember paying less than $90 for a brand new one around 1981.
Re: Re: Re: nad 3020 clicking sound when playing
This may actually explain all. The headphone connects to the same output as the speakers but through resistors. There is a thermal fuse at output which disconnects the speaker connection under excess current conditions. It may also click. Very possibly it requires a replacement. It's easy to test by short-circuiting it underneath the board. Before doing that it may be advisable to check output offset and bias current.
islanddancer said:
This may actually explain all. The headphone connects to the same output as the speakers but through resistors. There is a thermal fuse at output which disconnects the speaker connection under excess current conditions. It may also click. Very possibly it requires a replacement. It's easy to test by short-circuiting it underneath the board. Before doing that it may be advisable to check output offset and bias current.
Re: Re: Re: Re: nad 3020 clicking sound when playing
Thank you Sir.
I searched the web and got a schematic for it. I am not sure which is the fuse you are refering so I circled the one I suspect is the fuse. Could you please tell me if it is correct?
I have also got a picture of the 3020, could you please tell me which one is the fuse I need to replace.
analog_sa said:
Thank you Sir.
I searched the web and got a schematic for it. I am not sure which is the fuse you are refering so I circled the one I suspect is the fuse. Could you please tell me if it is correct?
I have also got a picture of the 3020, could you please tell me which one is the fuse I need to replace.
Attachments
It is marked as TB1/TB2 on your circuit and it's right between the zoebel and the output inductor. It's a bimetal automatic fuse and i have no idea if it's easy to find a replacement, nor do i know at what current it trips. 10A? My guess is that yours is tripping early. Or you really listen loud.
Not enough resolution to spot them on your board picture but they should be close to their corresponding inductors. Square cross section, about an inch tall, black, two pins at the bottom iirc.
Again: before replacing or shorting check bias and offset just to be on the safe side.
Not enough resolution to spot them on your board picture but they should be close to their corresponding inductors. Square cross section, about an inch tall, black, two pins at the bottom iirc.
Again: before replacing or shorting check bias and offset just to be on the safe side.
analog_sa said:
Hello Sir,
I already found TB1 and 2 on the circuit and on the schematic. they are rather tall black rectangular blocks.
My speaker is wharfedale diamond 9.1, 6ohms 86db.
The click will appear even when the volumn knob is at 9 o'clock.
Thank you Sir. I also found a fuse from the transform cracked.
It is F3. and it is a walter 4A 250V. Can I use a similar product to replace that?
analog_sa said:
The fuse is tripped by current - the headphones simply don't draw enough to trip it (limiting resistor and higher impedance) - or at least this is my working theory
Just check what is the output dc. There seems to be no bias control.
Also intriguing is that I removed the cracked fuse right after the transformer and the headphone still works fine.
I will post the DC voltage once I get it done. Already 4:00AM local time...
Thanks you Sir.
Hello islanddancer!
You are serching the problem in a wrong place!!!
I have made a clone of Nad 1020b, it's just preamplifier which sounds great and in the present time i ak still usin it .
So don't touch anything into the power amplifier, problem is in the preamp.
Please tell me when you hear that cracking noise during pushing input biuttons, you must hear the same noise when you also pushing on and off loudness button, and also when rotating the volume potentiometer?
When you make this test turn off all input devices connected to the inputs of Nad 3020.
PS: also try to test if that noise is always there, try to test several times of the day!!!
You are serching the problem in a wrong place!!!
I have made a clone of Nad 1020b, it's just preamplifier which sounds great and in the present time i ak still usin it .
So don't touch anything into the power amplifier, problem is in the preamp.
Please tell me when you hear that cracking noise during pushing input biuttons, you must hear the same noise when you also pushing on and off loudness button, and also when rotating the volume potentiometer?
When you make this test turn off all input devices connected to the inputs of Nad 3020.
PS: also try to test if that noise is always there, try to test several times of the day!!!
islanddancer said:
it turned out the one of my newly purchased speakers has problem and I returned the speakers bought a pair of dynaudio focus 110.
The headphone is having some problem now, sometimes the left channel will occasionally have cracking or hissing sound and even cut out for a few minuets. What is puzzling me is that after while it goes back to normal again. The speaker out has the same problem now. Formerly I don't have a single problem with the headphone outs, maybe I didn't listen to long enough with the headphones.
nad 3020 sounds really good, I have a new rotel ra 1062 amp, I don't think it sounds as good as the vintage 3020.
I wonder if I can find someone who has the same problem before, I want it to work fine very badly.
Thanks!
You can find this schematic here on the forum , aI also got this schematic.
First measure all voltages on the pre-amp section which is almost the same power supply for pre-amps in all nad amplifiers some nad's have a higher input voltages from the transformer and also a 50 or 63 volts elco's after the bridge rectifier, any how you should measure around 28 to 30 volts for positive reel and - 28 to -25 volts for negative reel, it is very strange that in all older models of Nad this voltages are not equal mirrored positive and negative, in some newer models this voltages are equal values positive & neg. around +28 gnd -28 volts.
You'll find measured voltages on every point on the pre-amp transistors so you can compare that from the service manual for eventual no matched voltage.Or just turn off and take a resistance measurement on every active element on the pre-amp, there are 4 transistors per channel and 2 diodes for the biasing ( in newer models is used 3 1n4148 in series for that)
Another thing which was mentioned here before: Perhaps you can try this firs on your solving test: Make a short circuit (bypass)Q509 & Q510( which is used for muting ) the pre - out:First desolder them both and solder wire from Drain to Sorse ( this are fets) and try it .
Next: if this wont help try to Re-solder all solder joints for some dry solder point. In the pre-amp take a look with just naked eye for this.
Next measure all coupling capacitors or replace them with new .
I hope this will help, because I cloned NAD 1020b pre-amp and non-stop is turned on and sounds pretty nice, But I modified this pre-amp and now I added tone defeat option and no loudness and sounds great. I have to replace coupling cap's but I can not find any better just theese only regular elco's nothing from audio cap's black gate or similar.
Good luck and of course that vintages sounds better than Rotel's specially Rotel pre-amps, Rotel amps are better than rotel pre-amps.
First measure all voltages on the pre-amp section which is almost the same power supply for pre-amps in all nad amplifiers some nad's have a higher input voltages from the transformer and also a 50 or 63 volts elco's after the bridge rectifier, any how you should measure around 28 to 30 volts for positive reel and - 28 to -25 volts for negative reel, it is very strange that in all older models of Nad this voltages are not equal mirrored positive and negative, in some newer models this voltages are equal values positive & neg. around +28 gnd -28 volts.
You'll find measured voltages on every point on the pre-amp transistors so you can compare that from the service manual for eventual no matched voltage.Or just turn off and take a resistance measurement on every active element on the pre-amp, there are 4 transistors per channel and 2 diodes for the biasing ( in newer models is used 3 1n4148 in series for that)
Another thing which was mentioned here before: Perhaps you can try this firs on your solving test: Make a short circuit (bypass)Q509 & Q510( which is used for muting ) the pre - out:First desolder them both and solder wire from Drain to Sorse ( this are fets) and try it .
Next: if this wont help try to Re-solder all solder joints for some dry solder point. In the pre-amp take a look with just naked eye for this.
Next measure all coupling capacitors or replace them with new .
I hope this will help, because I cloned NAD 1020b pre-amp and non-stop is turned on and sounds pretty nice, But I modified this pre-amp and now I added tone defeat option and no loudness and sounds great. I have to replace coupling cap's but I can not find any better just theese only regular elco's nothing from audio cap's black gate or similar.
Good luck and of course that vintages sounds better than Rotel's specially Rotel pre-amps, Rotel amps are better than rotel pre-amps.
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