Long time audiophile and repair video connoisseur here, only recently ran across your videos. _Really_ enjoy your concise, no fluff, straight to the point approach. Not sure why you don't have a bazillion subs, but it's NOT because of lack of quality of your content. Don't change a thing and just keep cranking them out - you've got a great recipe.
@dualityrepair4770
Жыл бұрын
I really appreciate this. A little feedback goes a long way.
@paulskvorc3627
2 ай бұрын
Totally agree with your sentiment and is reinforced by famed Paul Carlson's comment below. These videos for a budding hobbyist like me provide succinct, logical instruction. Job well done, and I look forward to more videos and deserved subs...
@Mac-t4y
16 күн бұрын
Most of the equipment that Duality has presented in this channel has: Low $ value due to age, OEM no longer support. I do recommend to work on McIntosh products which still in circulation even as old as 40 years old and McIntosh is one of the product that increase value over time.
@THOMMGB
Жыл бұрын
That was the best 7 minutes watching you troubleshoot this amplifier. Amazing. You make it look so easy, when, in fact, it's not.
@dualityrepair4770
Жыл бұрын
Thanks @THOMMGB.
@lcagee
9 ай бұрын
One of the best amplifier repair videos i have seen. Thank you.
@rickjames6948
9 ай бұрын
Okay, I'm IMPRESSED. Way to break it down smartly and in record time.
@Ro32da72
10 ай бұрын
So easy to follow, and some great fault-finding tips along the way. Also; no messing about; straight through the diag and on to the repair - great job.
@raygianelli3612
Жыл бұрын
Another great video. No cereal or filler, all red meat! You've got the best short form videos (which I'm a big believer in) I've ever seen on KZitem.
@dualityrepair4770
Жыл бұрын
Thanks Ray. Plenty of people love the long-form videos. I enjoy them myself. But like you say, everyone's busy and time is unbelievably valuable, so I like to keep mine concise. What I'd love to do one day, or see someone else do, is to post 2 videos at once. One long-form, one short-form, each documenting the exact same repair, and see how they perform head-to-head. It would be an interesting experiment.
@TravelOutlook
Жыл бұрын
Thanks Nick....loved the red "x" through the tested sections.
@dualityrepair4770
Жыл бұрын
Thanks for the comment. It's satisfying to reduce an issue from 100s of possible sources to just a few.
@mstorrente
Жыл бұрын
I like your direct style for explaining your method. Goodyear Jobs. Thanks.
@darrenmarrable2530
Ай бұрын
Thànkyou. I just learned so much good information.
@musictypefoundry7345
Жыл бұрын
This is awesome. Well explained and easy to follow. Can't wait for the next one!
@dualityrepair4770
Жыл бұрын
I appreciate the comment. Very glad you found it easy to follow.
@planetpeckham1
2 ай бұрын
What a super explanation! Subscribed.
@afzaalkhan.m
Жыл бұрын
Excellent and Concise diagnostic analysis. Thank you . Rawalpindi
@dualityrepair4770
Жыл бұрын
Thank you.
@johnbravo7542
Жыл бұрын
Excellent,thank you for uploading this trouble shooting method.
@ianmacpherson8385
Жыл бұрын
How cool was that? Highly informative and great delivery. Looking forward to the next installment.
@dualityrepair4770
Жыл бұрын
Thanks Ian. Glad you found it interesting.
@pascalphase2556
11 ай бұрын
I love your vids, amazing troubleshooting ! you gain a new subscriber from France.
@pantelisEVs
Жыл бұрын
Once again a very entertaining and informative amp repair! Thank you
@dualityrepair4770
Жыл бұрын
Glad you enjoyed it @pantelisEVs
@peterwikvist2433
5 ай бұрын
Great presentation Sir! Thank you for sharing.
@saarike
Жыл бұрын
Simply great!!! Thank you.
@gregpeirce6121
Жыл бұрын
Very clear and helpful instruction, thank you.
@dualityrepair4770
Жыл бұрын
Glad it was helpful!
@MrCarlsonsLab
Жыл бұрын
Great troubleshooting!
@dualityrepair4770
Жыл бұрын
Thanks Paul
@xpump876
5 ай бұрын
Nice trouble-shooting steps!
@bobmulhiemer7564
8 ай бұрын
Thank you sir!
@midmodaudio6576
Жыл бұрын
Great video, very useful and informative. Thank you !
@dualityrepair4770
Жыл бұрын
Thanks for the comment midmod.
@maryrafuse3851
Жыл бұрын
Interesting contrasting this NAD with amps of old that could run for decades without problems. Also the interior build quality in evidence with the Sony TA-2050, TA-F3A and Hitachi HA-330. All built in Japan.
@MMc-p9g
Жыл бұрын
Fantastic video! So straightforward and clear! This is the first video of yours I have watched. I will definitely check out others. Can I ask if you test ESR values to find bad caps too?
@dualityrepair4770
Жыл бұрын
Thanks for the comment and I’m glad you found my channel. I do use an ESR meter as you’ll see in some of my other videos. I didn’t use it here since both caps failed for capacitance.
@dpyles9396
Жыл бұрын
Excellent method
@ElectoneGuy
Жыл бұрын
These 1980s NADs are excellent amps, but they suffer from the use of cheap components that were used to keep the costs down. A full re-cap is almost always necessary.
@dualityrepair4770
Жыл бұрын
Agreed. This video only shows the troubleshooting / repair. It will receive a full service (including a full re-cap) before I'm done with it.
@maryrafuse3851
Жыл бұрын
Cheap components do not make for a good amp. In the 1970's Sony and others managed to deliver high quality amps featuring great design, build and components. This NAD is a sad little amp.
@ElectoneGuy
Жыл бұрын
@@maryrafuse3851 Bullshit. The 3240 is both a powerful and transparent sounding integrated. Rated for 40w/ch, the Power Envelope circuitry with +6db of headroom will easily crank out 160w/ch for real-world musical peaks. And, it does it while delivering excellent sound quality. Their main goal was to counter Japanese flashiness with simple, good sounding equipment at a fair price. In order to do that, they had to sublet out their manufacturing to third party factories in Taiwan and later China that used questionable longevity capacitors.
@bobisyouruncle1
18 күн бұрын
NAD is overrated. If 6db headroom is your aim, well, that, nad is good at.
@gillanland
Жыл бұрын
Incidentally i also recently purchased 3240PE amp and your video is the only repair video that i could find!. Mine works, those capacitors haven't failed yet but looks like it needs full sevice( very old capacitors, corrosive glue, dry heatsync compaund and darkened areas on pcb from possibly overheating) . If you deside to make a video on full servicing i'll follow your steps. I have a question as well, there are some sort of breakers BK-1,2 A-40 on the output, i guess they are for DC protection but they are not relays so i don't really understand how they work. Thank you.
@ewhibs
9 ай бұрын
Noob like me finds your vids essential
@nun9496
Жыл бұрын
Nice Neat and Clean !
@reinhardengling2227
Жыл бұрын
Gut erklärt, Danke.
@dualityrepair4770
Жыл бұрын
Gerne!
@peter.stimpel
Жыл бұрын
Nice lesson
@dualityrepair4770
Жыл бұрын
Thank you
@bobdoritique7347
Жыл бұрын
Merci for this video.
@dualityrepair4770
Жыл бұрын
de rien
@briancoish1695
Жыл бұрын
Nice one.
@dualityrepair4770
Жыл бұрын
Thank you
@tjules7
Жыл бұрын
I like the way you go through that process of elimination until you pinpoint what the problem is. Very efficient. I live in North Carolina; I have an NAD receiver 7400. I have not used it for years and recently, I tried to turn it on. Sounds is coming in and out and at times, it sounds like what you hear when you radio is not using the correct frequency. How can I go about having somebody looks at it? Do you know a place in North Carolina I can go to, by any chance?
@dualityrepair4770
Жыл бұрын
Hi Tony. I'm in Minnesota and unfortunately I don't know anyone around your area who might be able to help you. I might look at it if you'd like to send it up. If you want to talk more, email me at nick@duality-er.com.
@rickjames6948
9 ай бұрын
Where do you repair guys get the schematics from?
@davidstevens7809
Жыл бұрын
Seems like it should have dc output from that opamp.. and yes it would be see as a fault to the comparator that controls the relay. Im confused why i dont see any zeners being used with those dropping resistors and caps.. I would increase the cap values and the resistor wattage. So it wont happen again.
@test40323
Жыл бұрын
Huh, nice deductions. How do you find schematics for old equipment like this? Thanks.
@dualityrepair4770
Жыл бұрын
Thanks for the comment. HiFi Engine is a great resource for manuals, which is where I found the schematics for this amp. If I can't find what I'm looking for there, or anywhere else online, I've also purchased manuals from servicemanuals.net. Usually they're $10 to $20.
@test40323
Жыл бұрын
@@dualityrepair4770 , thank you!
@simonstergaard
Жыл бұрын
could you do a video explaining how to inject the sine, and what are those 2 brown things on you wall that its connected to? i want to learn this
@dualityrepair4770
Жыл бұрын
Yes absolutely. Good idea.
@N2YTA
Жыл бұрын
Didn't you rule out the power supply when you demonstrated that the power amplifier worked?
@dualityrepair4770
Жыл бұрын
Not quite. The power amp uses the other 2 sections of the power supply (43V and 71V). I had to rule out the section of the power supply used by the preamp (20V).
@Mr-Speaker99
9 ай бұрын
❤🎉❤
@tenminutetokyo2643
2 ай бұрын
Do a Carver m-400t cube amp.
@dualityrepair4770
2 ай бұрын
I did the plain M-400. DR #37.
@quantumkid1097
Жыл бұрын
Where are you located?
@dualityrepair4770
Жыл бұрын
MN (55129)
@marekwaczynski3894
Жыл бұрын
So again CA is tricky with low quality-short lifetime caps.
@kilgoretrout4461
Жыл бұрын
Thanks for these great tutorials.
@jrworpjrworp7254
Жыл бұрын
Goof video, shows exzellent how to search for faults
@Hr.0ldenberg
Жыл бұрын
Moin, der Mann hat absolut keine Ahnung, wie man ein Verstärker vorab prüft. Er hat wieder einen scope noch ein Sinus Generator noch belastungs Widerstände. Somit ist das ganze Video was man hier sieht für die Tonne. Junge Leute, die gerne etwas lernen möchten sollten sich nicht an dieses Video halten ‼️👈 Dieser Text wurde per Ki erstellt und kann Fehler enthalten. Die hauptaussage dass der Mann keine Ahnung hat bleibt aber erhalten!!!!!
@davidstevens7809
Жыл бұрын
Oh my.. when i saw you use solder wick.. i looked at the ground. The caps cant cause the problem..with them off the board you should still get a voltage on both sides of the dropping resistors.. the caps give you stability. All of the solder looks dry..come on if your gonna teach. Stop blaming the caps. You simply do continuity test and youll find no connection between the rear of the resistor and the pin on the ic.. second thought.. the signal ground has bad connection also..thats the only way the voltage could go up on the other rail
@helixworld
Жыл бұрын
If the power supply is unstable, the RC circuit of the tone control can cause it to oscillate. Then the muting circuit stays open and there would be no output. Anyway, I guess that is one possible explanation.
@KuntalGhosh
Жыл бұрын
That is the worst heatsink i have ever seen on an amplifier..
@envisionelectronics
Жыл бұрын
You have to understand how power envelope works to know why this heat sink is good enough.
@dualityrepair4770
Жыл бұрын
This was a very messy amp. Something was spilled in there at some point, that's what some of the residue is on the heat sink. It's a miracle that it works at all. I wanted this video to highlight the troubleshooting and repair only. This amp will be fully serviced before I'm done with it.
@Andrew-rc3vh
Жыл бұрын
The internals are cheap all round. 5% carbon film resistors are noisy, ceramics are dirt cheap poor tolerance, even the PCB is cheap. There is nothing at all pretty inside and reminiscent of the build quality of a Hong Kong/Taiwan import of the era. Oh and the hifi mags called it a "Best-Buy"!
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