Hi, Just purchased a NAD T763 receiver which is great but seems to cut out on thermal overload very easily. Temp on top of vents is 125 F when it trips, anyone else had the same prob?
I had that problem with a T762 that I bought last fall. Long story short, I returned it and went with the T763, which,according to NAD has an improved cooling system over the 762. I haven't had that problem with the 763 so far.
geoffmurray
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yep, the fans are working, 2-3" clearance either side and heaps underneath ( sitting on bricks), 3/4 clearance on top.
I'd try nothing on top and see what happens. Maybe the heat isn't dissipating quick enough. Then if it still overheats I'd suggest a warranty fix or return for another unit.
I would suggest more room on top too. That just doesn't sound like enough room to get the heat out. It doesn't matter how good the cooling system is if the heat has no place to escape to. I have my 762 in an enclosed cabinet, and have had no trouble with heat. When I am doing any serious use of the receiver (i.e. when watching a movie), I clamp a cheap mini-fan to my entertainment center and point it directly at the top of the receiver. It makes a world of difference.
I've got my 763 on the top shelf of my rack. Nothing above or to the sides. Lot's of room to breath and very easy access to the back. My receiver never runs very hot, although my 762 woud get REALLY hot and it was on the top shelf of the same rack.
geoffmurray
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Ok will try the extra space on top. Interestingly, I talked to a hifi electronics technician re the problem yesterday and he made the comment that it is more than likely a current overload than temperature and that I should look at my speakers. They are Duntechs which are difficult to drive. I checked the speakers as best as I could last night and found no faults although I had already noticed a lost tweeter yesterday morning. Replaced the tweeter with a spare I had and........ it cut out again this morning at a temp reading of 32 deg C i.e. not hot.:-( He also suggested I run one speaker at a time to determine if it is a particular speaker causing the prob. That is happening now.
geoffmurray
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Hi again, Could someone with a T763 check to see if the fans blow air DOWN out of the bottom of the case or not. Mine do and it seems a funny way to exhaust heat as hot air rises!! Ta Geoff
Well all be damned. I just checked under my unit and it is moving some air out the bottom as well as the top. I've never noticed that before on any amp or receiver i've owned. Hmm...
What ratings do your Duntechs have? I noticed on the back of the 763 that it says 8 ohm min impedence for l/r, 4 ohm for centre, rears and back surrounds.
geoffmurray
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The Duntechs are difficult to drive, they are rated at a nominal 4 ohms with an actual range of 3.5 to 6.5 ohms
I think clearance on the top is absolutely the most critical. 3/4 inch (assuming that's what you have) is definitely too little clearance. I have mine in an enclosed cabinet (open in back) and set my shelf to give me the maximum on top I could which is like 8-10 inches.
I think the fans are on the bottom.
I would check the speakers/speaker wires too. I recently went rounds with a Yamaha receiver that fried the tweeters and crossovers in a few of my speakers before I got my T773.
When I was demoing a T763 at home a fried tweeter in one of the speakers that I wasn't yet aware of kicked the T763 off (protection circuit). The only way to reset this was to turn the power switch on the BACK of the unit off and then on again to reset it.
geoffmurray
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Narrowing it down here. I have tried running the NAD with soft clipping turned off and so far so good. I ran it for 2 1/2 hrs this afternoon at +5 dB playing solid rock and it didn't trip. Appears to be a problem with the soft clipping circuitry. Geoff