Question about NAD 712
The main display is no longer visible. It appears that the backlighting has stopped working.
The lamps i use on all NAD displays(and have done since the early 1990's) last heaps longer.You can get them from RS components in your country. They are a 14v 37ma type, and seem to last. Never had any come back for replacement again. P/N 351-9585. Increasing the ballast resistor where fitted by 25% in valua also helps preserve them
Posted on Jan 27, 2008
I've encountered this same problem on two 712s. There is a pair of bulbs behind the display that burn out. (Only one has to burn out to disable both because they are wired in series.) My local shop charges $50-75 to make the repair, mainly because of the handling PIA in getting to them. It's actually not that hard. I took the cover off, unclipped the simple circuit board to which the are attached from behind the display and removed the bulbs using a soldering iron. I tested supply voltage and resistance on the good bulb. (I forget them both but I'm sure NAD CS could help.) I picked up two that were kind of close (as close as I could get) from Radio Shack and soldered them in: voila. It was really easy. HOWEVER, those bulbs, because they weren't a match to the originals burned too bright and burned out within 3 weeks. It's doable to repair yourself as long as you have a #2 phillips driver and a soldering iron. Don't start though, until you get PROPER replacement bulbs. (If you find out the specs, I'd be happy to know.) Good luck Nick
Posted on May 02, 2007
If you know you're way around the insides of receivers, or if you see you're repair person scratching his/ers head too much- there's a service note on the AV716 which mentions R921,922,923 (0.47 ohm) and R924 (33 ohm) resistors opening for no reason. Change them all from .25 watt to 0.5W of the same type. They are located on the main PC board 2 are in series with the transformer windings, and 2 are in the power supply. I've also noted that soldering in this unit might need some touch-up. REMEMBER the numbers I've given you are for a NAD AV716, so they might be different from the 712. Good luck, again
Posted on Jan 30, 2006
If this receiver display is like many others, the display has a backlight. It could be an incandescent lamp or electroluminesent panel.
Lamps are easy once you find out what the original is.
The other? not so easy. Take it to an tech who can get NAD parts and have it replaced.
Major troubles like "most things not working" are power supply issues especially if the main fuse is good.
For Danny....Try another good speaker on THAT channel and make sure the "ohms" rating is within + - 2 ohms
Posted on Feb 28, 2008
If you can see the info when there's light in the room, but there's no light in the display you probably need to change the lamp/LED that lights it. If there's no info at all then it's a bit more complicated and i can't give you a straight answer at the moment, but post your question again(as a new problem) specifying whether the info is visible at all or not. It could also be that your display has a dimmer, and somehow you managed to switch it on and the value to 0. Good luck, NAD makes really nice receivers, take care of it.
Posted on Jan 30, 2006
SOURCE: NAD 712 Display unit
On my system the bulbs burned out some time ago. Today, I bought a pair of 12v micro lamps at Radio Shack (part 272-1092). Then removed the board behind the display and replaced the bulbs. This required some soldering. The bulbs have held up for more than 6 hours, so I do not think they are going to burn out.
Posted on Apr 06, 2009
The contacts in the A B speaker selector switch had degraded on my NAD 7130 receiver. Distortion and signal loss would come and go. Contact cleaner and wriggling the swx knob became useless. Then, years ago I jumped the swx with small lengths of bare wire and tinned the whole thing with solder. Never had a problem since and it probably improved the receiver because it eliminated a component in the output stage that could (and did) introduce distortion.
Posted on May 26, 2009
SOURCE: NAD 7140
If you're unsure of the input to use; I would normally use the CD input but as you're already using that I would use the AUX input. Don't use the Phono inputs as they are too sensitive.
Posted on Dec 16, 2012
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