And another great video. I had a Nad 716 brought it for repair and the shop when bankrupt lost my receiver made a claim at the police station but they told me that they couldn't do nothing for me. Received back my receiver two years after don't know where it was coming from but it was all bang up and didn't work anymore. I love that receiver 5 channels pro logic the sound in stereo was amazing it was a thousand dollars Canadian at the time.
Thank you for this video. I have a NAD receiver 7400. It's working for the most part but the right speaker tends to go off and I have to play with the knob to get it to a decent level; the bass and treble do not respond properly; sometimes they work; sometimes they don't. Where are you located? Would you be able to take a look at it for me?
Some people think they will get higher current if they set the switch to a lower impedance, but the opposite is true. The lower impedance settings are there to limit current, because the amp can't fully handle such low impedance. Your test proved what I am referring to.
I just bought one off fleabay. The power amp worked but not the preamp, thanks to your video I went right to the +12 V which had exactly the same problem yours did. I just resoldered the joints around the regulator and it works now, I'll have to figure out exactly what I'm going to do long term. Maybe I'll substitute a 68 ohm 10 W chassis mount resistor if I can figure out a place to mount it. Thanks so much for the clue as to where to look!
I just read the temperature of the resistor on the +12 V regulator with an IR camera, it's over 300 deg F! Looking at it again I think I'll get 2 16 ohm 2 W resistors and put them in series.
I'm also looking at setting the bias, rather than putting the 1 ohm resistor in I'm going to monitor the voltage across R467 to get 0.22 * 30 mV = 6.6 mV, or maybe a bit more to allow for the addition of the base current. that will give me the same 30 mA idle current. I guess NAD figured that most tech won't have a 4 1/2 digit DVM to accurately read 6 or 7 mV.
Hi Trevor, Great video! Could you please provide step instructions on how to remove the front panel for the NAD 712? At the 6:59 mark on the video the front panel has been removed but you did not show how this was done. I have a NAD712 and cannot seem to remove the front panel even after removing all of the visible screws that seem to be holding it in place (this is after removing the top cover - which is easy). Many thanks for helping with this!
Thanks for this video. I have a 712 and I’ve lost the ability to tune in FM stations. Scanning or manual tuning...just static. AM still works perfectly.. Do you have any experience with the tuner section of 712? Is there anything a nube with a soldering iron and a DMM can look out for and hopefully fix? Also, is there a trick to accessing the trace side of tuner section. Taking bottom panel off still leaves tuner section inaccessible. Thanks so much!
I can't diagnose through the youtube comments but I can give you a few things to look for to give you a start. Get a schematic for your 712 from hifiengine and have a look at where the power feeds into the FM portion of tuner. Check to see power is supplied to all the chips. It appears the tuner is run from the +12v supply and there are several fusible resistors in these supply lines. With the schematic you can see where these fuses are and their values. The only way to access the PCB btm is to disassemble, I know it's a pain. Hope that helps
Hi, I was wondering if you had on thoughts about an issue I am having with my NAD 712. It is fully functional, but when it is powered off (not in standby but button pressed off) if occasionally makes a clicking noise. The led on the Aux or CD lights up with the click. So, far it hasn't stopped working but the clicking has me a bit worried. Any ideas what it could be? I am pretty handy. If it is an easy fix I might be able to fix it. Also, is it safe to leave it in Stand-by mode, or should I leave shut off normally. Thanks.
Hey again. I just got home my new leds for the reciever, but it got med wondering... Why do i need a new resistor for new led's that are the same as the old led's? 🙂🙂👍👍
Thank you for posting this video. It seems after viewing and comparing modern vs. vintage repair videos, the modern amp's seem to have much more heat staining/damage visible on the circuit boards (like this one did) while producing much lower wattage than their vintage predecessors. Is the simple explanation the modern circuit design and plethora of IC chips?
Hi Craig, I don't think it's a simple as that. There are lots of variables at play here, hours of use, build quality, circuit design & layout, quality of components, environment of use and so on. I think NAD did ok in all these areas and provides a good quality product that lasts at least 20 years or better. I do notice their build quality isn't top priority but they do make a great sounding product. It's true modern gear tries to scale down on costs by miniaturization and lowering parts counts, this is where they compromise long life. Thanks for the comment and watching :)
@@cheslynholland1487 Judging best build quality would be difficult because all manufacturers evolved throughout the years and changed manufacturing processes. Most of the changes were made to improve profits when the market got tighter. And you guessed it, when they targeted cost cutting, build quality went down as well.
Not overly. I've seen amps with 22,000uF caps and they're constructed the same, transformer, bridge, caps without any special considerations. Maybe one day I'll set up for measuring the inrush currents and experiment with different cap values
I have a mint 712 that functions great but I’d like to get it recapped. Can I get that done by you? Send it in? Thanks. *It pulls radio stations in from the next state with no antenna. A very powerful tuner.
Where did you buy the warm White leds for the display? Can you link it, would be awesome. I have a question about my nad c521 disc player.. what bulbs should i install to the display baclight?
@@sebastianm.t3184 Hi, I did look at the schematic for the C521 and that player uses a Electroluminescent panel to illuminate the LCD. It uses a tiny inverter to step up to the voltage it needs to light. The inverter may have a bad cap or the EL panel itself is worn out. You can buy new panels if you knew the size of yours & just replace it Doing a LED retrofit might not look good on the C521
And another great video. I had a Nad 716 brought it for repair and the shop when bankrupt lost my receiver made a claim at the police station but they told me that they couldn't do nothing for me. Received back my receiver two years after don't know where it was coming from but it was all bang up and didn't work anymore. I love that receiver 5 channels pro logic the sound in stereo was amazing it was a thousand dollars Canadian at the time.
Hi Bruno, sad story for your 716. Did you manage to get it working again?
Thanks
No I couldn't fixe it it was in really bad shape went I got it back.
Thank you for this video. I have a NAD receiver 7400. It's working for the most part but the right speaker tends to go off and I have to play with the knob to get it to a decent level; the bass and treble do not respond properly; sometimes they work; sometimes they don't. Where are you located? Would you be able to take a look at it for me?
Some people think they will get higher current if they set the switch to a lower impedance, but the opposite is true. The lower impedance settings are there to limit current, because the amp can't fully handle such low impedance. Your test proved what I am referring to.
I just bought one off fleabay. The power amp worked but not the preamp, thanks to your video I went right to the +12 V which had exactly the same problem yours did. I just resoldered the joints around the regulator and it works now, I'll have to figure out exactly what I'm going to do long term. Maybe I'll substitute a 68 ohm 10 W chassis mount resistor if I can figure out a place to mount it.
Thanks so much for the clue as to where to look!
I just read the temperature of the resistor on the +12 V regulator with an IR camera, it's over 300 deg F! Looking at it again I think I'll get 2 16 ohm 2 W resistors and put them in series.
I'm also looking at setting the bias, rather than putting the 1 ohm resistor in I'm going to monitor the voltage across R467 to get 0.22 * 30 mV = 6.6 mV, or maybe a bit more to allow for the addition of the base current. that will give me the same 30 mA idle current. I guess NAD figured that most tech won't have a 4 1/2 digit DVM to accurately read 6 or 7 mV.
Hi Trevor,
Great video! Could you please provide step instructions on how to remove the front panel for the NAD 712? At the 6:59 mark on the video the front panel has been removed but you did not show how this was done. I have a NAD712 and cannot seem to remove the front panel even after removing all of the visible screws that seem to be holding it in place (this is after removing the top cover - which is easy).
Many thanks for helping with this!
35:10 which Deoxit product you apply to the LED wiper tracks?
Thanks
Thanks for this video. I have a 712 and I’ve lost the ability to tune in FM stations. Scanning or manual tuning...just static. AM still works perfectly.. Do you have any experience with the tuner section of 712? Is there anything a nube with a soldering iron and a DMM can look out for and hopefully fix? Also, is there a trick to accessing the trace side of tuner section. Taking bottom panel off still leaves tuner section inaccessible. Thanks so much!
I can't diagnose through the youtube comments but I can give you a few things to look for to give you a start. Get a schematic for your 712 from hifiengine and have a look at where the power feeds into the FM portion of tuner. Check to see power is supplied to all the chips. It appears the tuner is run from the +12v supply and there are several fusible resistors in these supply lines. With the schematic you can see where these fuses are and their values. The only way to access the PCB btm is to disassemble, I know it's a pain. Hope that helps
Hi, I was wondering if you had on thoughts about an issue I am having with my NAD 712.
It is fully functional, but when it is powered off (not in standby but button pressed off) if occasionally makes a clicking noise. The led on the Aux or CD lights up with the click.
So, far it hasn't stopped working but the clicking has me a bit worried.
Any ideas what it could be?
I am pretty handy. If it is an easy fix I might be able to fix it.
Also, is it safe to leave it in Stand-by mode, or should I leave shut off normally.
Thanks.
Hey again.
I just got home my new leds for the reciever, but it got med wondering... Why do i need a new resistor for new led's that are the same as the old led's?
🙂🙂👍👍
No, re-use the old resistors if you can
Thank you for posting this video. It seems after viewing and comparing modern vs. vintage repair videos, the modern amp's seem to have much more heat staining/damage visible on the circuit boards (like this one did) while producing much lower wattage than their vintage predecessors. Is the simple explanation the modern circuit design and plethora of IC chips?
Hi Craig, I don't think it's a simple as that. There are lots of variables at play here, hours of use, build quality, circuit design & layout, quality of components, environment of use and so on. I think NAD did ok in all these areas and provides a good quality product that lasts at least 20 years or better. I do notice their build quality isn't top priority but they do make a great sounding product. It's true modern gear tries to scale down on costs by miniaturization and lowering parts counts, this is where they compromise long life.
Thanks for the comment and watching :)
@@TrevorsBench hey man great video very interesting. As someone who fix a lot of amps, what brand would you say stands out as best build quality?
@@cheslynholland1487 Judging best build quality would be difficult because all manufacturers evolved throughout the years and changed manufacturing processes. Most of the changes were made to improve profits when the market got tighter. And you guessed it, when they targeted cost cutting, build quality went down as well.
Any concerns about in-rush current from the 6400uf of extra capacitance now?
Not overly. I've seen amps with 22,000uF caps and they're constructed the same, transformer, bridge, caps without any special considerations. Maybe one day I'll set up for measuring the inrush currents and experiment with different cap values
I have a mint 712 that functions great but I’d like to get it recapped. Can I get that done by you? Send it in? Thanks. *It pulls radio stations in from the next state with no antenna. A very powerful tuner.
Sorry, I'm currently only taking items from my local clients
I have one of these. The volume knob LED flashes when I change the volume with the remote.
Sounds like a design feature
Where did you buy the warm White leds for the display? Can you link it, would be awesome.
I have a question about my nad c521 disc player.. what bulbs should i install to the display baclight?
I purchased the LEDs from Aliexpress. Go there and search warm white led and you'll see several different case styles to choose from
@@TrevorsBench thanks a Lot 👍 what about the resistor?
@@sebastianm.t3184 Hi, I did look at the schematic for the C521 and that player uses a Electroluminescent panel to illuminate the LCD. It uses a tiny inverter to step up to the voltage it needs to light. The inverter may have a bad cap or the EL panel itself is worn out. You can buy new panels if you knew the size of yours & just replace it
Doing a LED retrofit might not look good on the C521
They had a tendency to lose one channel.