20 Most Recent NAD C320 2-Channel Amplifier - Page 4 Questions & Answers

Hi davidfluff

You need to check around the output stages for dry solder joints. Then also replace the BD139 bias control transistor on the heatsink with a 2sd669. The BD139 can be prone to thermal runaway in this circuit Then setup the bias current and DC offset in the output stage. If you are not familiar with the things that I have just told you, you need to contact a technician, if you mention these things to him, then you stand a fair chance of getting it sorted out.

I am more than happy to answer any other questions you may have about it, please get back to me here, or use the ASK function to go straight to me :) If you are still unsure, have problems, or we need to look at the situation more deeply, then before you give a rating for this advice, hit the ASK button Thanks for using FixYa, If you consider the advice I have given you as sound, a FixYa rating is a great reward for my efforts to help you. Cheers.

regards
robotek

pre out from nad---------to 2 rca input in sub.

take audio out from tv and insert it in aux in in your amp.

if you did test for your cable and speaker and you find it fine-your problem will be in output stage of your amp and needs aid of service center.

You need to provide me the specs of your amp, your speakers. Impedance important. You are experiencing overload, overheating caused by overload. You have a wider frequency range using a mixer and that affects the output stage of your amp and can cause to fail.

I am from Yamaha service before and they have speakers that has 4-6Ohms impedance only. And you have to know your amp if capable of handling such low impedance. you may not have problem with the power but it should be impedance.

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If your amp is under warranty, bring it to the nearest service center to have it fixed. But if not, and you know a little electronics, check for the bloated capacitor and/or a burnt resistor on the audio module and replace it. still not working, change the audio I.C. of the amp. If you don't know electronics, bring it to the electronics shop. Audio coming out of the headphone is different form the audio of the speakers. Sounds on your headphone is coming from the preamp circuit. That explains why the headphone audio is ok.




A Simple Thanks is Good Enough

NAD is know for loose connections, you have to get to the bottom of the pc board and look for cracked solder or solder that doesn't look shinny anymore.

May be dirty lens get a cleaning disc for cd player and insert to clean then try player again. If you can take cover off insert disc see if disc spins,if not spinning you need a motor drive.

what was your amp? ic or transistorized? the output transistor of your amp may be opened, mostly it will short but because u still hear sound, maybe open and only the driver transistor are working. replacing output transistor or IC could solve the problem.

You have a fault in the power amp. Identify the faulty channel by following the input leads. As, a stereo amp is basically two mono amps put together. You can compare the bad channel with the good one. First thing to do is a visual look around. If you see something odd looking in one channel and it's the faulty one, compared with the good channel, you might have found the cause. Look at the devices or device on the heatsink especially. If nothing stands out, the next thing to do is test the channels. You can do this in two ways. First, by touching the parts on each channel (with power on) with an insulated screwdriver. If you get a buzz in one channel and nothing in the bad one, in the same places of course! You might have located the faulty device. You can do the same with a volt meter. The readings should be the same in each channel. Work forward from the end of the preamp stage. Don't bother with the power supply parts, as they are common to both channels. By the way, don't short anything!

Distortion is categorized in Hum, Motorboating etc. Anyway see page 9 of owner manual for help. NAD C325BEE AMPLIFIER OWNER'S MANUAL ' ManualsLib For further help see page 24 of Service Manual NAD C 325BEE SERVICE MANUAL Pdf Download ' ManualsLib

I have nad t748 but not switching on the power on tha auto turn off

It is funny, I was just reading an article today about New Acoustic Dimension Cassette decks saying they were top of the line and equal to Nakamichi. The most likely reason is that the volume control needs cleaning with Electrical Switch Cleaner. You would have to remove the case and look. It is worth a quick spray. This says it has a motorized volume control. https://www.google.com/search?q=nad+1600+receiver+volume+on+high+volume ..

You can find volume and balance control components for the NAD 1300 preamp from a variety of sources. You can check with NAD directly, or look for parts on websites such as eBay or Amazon. Additionally, you may be able to find parts from audio/electronics shops in your local area.

NAD (New Acoustic Dimension) was all the rage when I was into composite audio in the 1970s. Not sure why would want to tweak that sweet clear natural sound like the performers played it. Your problem will be that you are loading an amp to a pre amp. https://www.google.com/search?q=Nad+2600 https://www.google.com/search?q=Nad+3020 https://www.google.com/search?q=nad+3020+nad+2600+graphic+equalizer ..

Does it occur on both channels at the same time, (power supply) or independant channels, (coupling capacitor).

Hi aartman

Yes it does have backlamps.

They are soldered to the PCB so you will need a few tools like a soldering iron, philips screwdrivers, solder, and some replacement lamps. Replace the lamps with this type from Farnell electronics. They have a 15000 hr life expectancy and last alot longer in the unit. I have tried many types of lamps over the years, and found these are the best choice if you want them to last.

FOR YOUR SAFETY-BE SURE TO DISCONNECT FROM THE MAINS BEFORE REMOVING THE LID

To get access to the lamps, you need to pull the main PCB out of the chassis to then get access to the bottom side of the printed circuit board where the 2 screws that retain the white lamp reflector assembly. Change both lamps with the type I mentioned,
Be careful not to flex the LCD display that is now exposed, it is quite fragile with the support of the lamp reflector cover no longer in place. ... reverse procedure to reassemble and away you go.

I am more than happy to talk about this solution with you further. Just ask away. Cheers

regards
robotek

I'm going to assume that you mean it jumps around, volume up/down by itself? If so, you have a bad rotary encoder. If you are interested in having your NAD repaired, please visit my website at audioserviceclinic.com. You may contact me there. Thank you.

This is the technical solution, you have to open the unit:Locate IC33 and connect pin 6 to ground, connect power, and then remove the ground connection at pin 6.The unit will then boot up in factory default.Henrik Pedersen