NEC A-11 Reserve II Integrated Amplifier Repair Solder 'N Chat (No Schematics)

[@isoguy.]

No snotty comment here from me as I really enjoy these long chatty vids becauce I learn somuch from them. What a monster amp, guess most of this would fit into a few chips these days and weigh virtually nothing. Thank for taking ths time to spread your knowledge via practical demonstration.

[@retroriff]

Tony, you a very brave man in trying to fix this NEC amplifier. Hope that customer pays well, because not many would go thru the paces needed to get these things up and running. Would do that kind of work only for restoring really nice pieces. Thanks for doing a great video despite your faulty camera ! Greetings from Canada.

[@lawrencesherman8435]

Tony; My attitude to long videos is that your remote has a fast forward. Myself, I LOVE seeing ALL the nitty gritty. Folks miss the real value of these kinds of channel - it is to live vicariously when we cannot do it ourselves. That is why details are great!✝

[@repairfreak]

I love your Channel Tony. Brings me right back to all my joy & frustration of many repairs years ago. I must next soon find the motivation to restore an old Sansui 9090 that someone gave me a couple years ago. BTW Tony, you might want to consider removing that circular electrical conductor from your one finger my friend. 😎👍

[@radio-ged4626]

Your Peak component tester comes from Buxton in North Derbyshire, England, UK. They are based in an area known as The Peak District - hence the name. I live about 90 minutes drive away from them. 🙂

[@pistachioaudiophile]

Love this long stream of consciousness format Tony! Seriously. Constantly on pins and needles what might happen next!

[@kozkoz7776]

these are the most under rated amps out their if you have a nec dual power supply amp its a keeper cant wait for part 2 of your show I have an nec ava 505 80 watts per ch bought it back in the mid 80s its fantastic sound use it for movies not music have other hi end amps but this is analog as it should be i truly love its sound

[@calvinrichardson3562]

Tony I thought that tape deck was really inexpensive but upon looking for one on EBay in decent condition was above what I was looking to spend and it has features that I wouldn’t expect at this price point like XLR connectors. Good video as always. Keep it coming. You always make me laugh. “Fortunately I keep my feathers numbered “

[@jamesclawson9156]

Always waiting for new show love it ,like allways. Keep on witn grins and giggles

[@cremvustila]

I really enjoy longer and chatty videos Tony and your short stories are also fun to hear. It's just relaxing to watch, happy subscriber here!

[@johnnytoobad7785]

"....And you can short crap out..." You are not alone....😈 Mr. Murphy is (once again) having a field day.

[@TrevorsBench]

Sparks are flying. So, it's not just me, lol What a weird design and no documentation to help you ... sure tests your skills. Good job Tony! !

[@rossthompson1635]

Loved this long video. You kept me company on a long train journey across Switzerland - so two enjoyable experiences for the price of one :-)

[@MarcelMourits]

Great video as allways. Concerning the Sony ZV-1 camera shutting off: in the menu setup2 set auto power off temp to high will make it shut off less fast. It seems to get quite warm in 4k mode. But the FDR-AX 43 camcorder is great, good buy!

[@VIPINSAINI_20]

really liked the video, you are awsome

[@kens7746]

Big fan of anything to do with audio repair and learning about different amps. I really liked the mini oscope. If you have any info on where to buy. That to me was a perfect signal tracer.

[@petertimp5416]

Good job Tony!!

[@ottodydaktyk]

Cool! Another Rush fan!

[@johnnytoobad7785]

Sony used 150+ volts on their phono stage for the TA-2000f preamp. Technics also used high voltage for their phono stages.

[@dhpbear2]

Does the camcorder stop at exactly 1:00 or 2:00?

[@peterjmcgee4680]

And then you have customers that ask you why it's so much money to have it. Serviced, you should tell him to go look at this vidyo. The sea why cool so much to have these things? Serviced, it's not a 123 thing to have done, it's very time consuming. And tedious work and sometimes they don't understand this myself as a sidekick. I restore vintage amplifiers and receivers. I do about 3 a month. That's it. I will not do anymore. And I have people keep knocking at my door ringing. My phone ask me why I don't do anymore because I'm 70 years old. I have other things to do with my life. Besides fixing the air vintage equipment. And I'd rather get on with it than spending a time at work bench. Would I spend a lot of life at all right? I have other things to do. And these people don't understand that and then when you hand them the bill. They look at you like your core side and then tell him. Will you try to find the parts and you pay the high prices of the parts and you sit there for hours on end, taking the equipment apart and finding the problem, repairing the problem and making sure that everything else is working properly, so you don't have to come and bring it back to me because something else. Went wrong. I was taught as a youngster. You do a job once you do it, right? So you don't have somebody coming back to bust your chops. And that's the way I've always done my work. When I'm seeing leaves my workbench and goes home to its owner. It's going to Burke, it's not going to explode. It's not going to spark, it's going to work and it's going to work perfect every time.

[@garygranato9164]

thank you tony cant wait for part 2

[@SeanBZA]

Yes 1980's era SRBP board is very prone to cracking, and also the only thing holding the copper on is the soldermask, with them being very sensitive to both heat and vibration, as the pads always tend to break loose. For jumper wire I always go for the good old tinned copper indoor phone wire, easy to get, and if you get a few meters of a multicore cable, easy if you know people who install telecoms, or go to old buildings being renovated and grab a few lengths out of the dumpster. tinned copper under the PVC, and also multiple colours for putting links. The bypass on the electrolytics is because they knew the old 1980's era capacitors were very inductive, being wound with leadouts on opposite ends of the foils, so they would have a self resonant frequency in the mid audio band, so the film capacitor, with schoop ends, was a very cheap method of reducing it, instead of buying the much more expensive electrolytics that had extended foils, that were spot welded to the lead in multiple places. Though unless it was 1uF and above not useful, though it did help with RF rejection, and reducing the noise from the diodes in the power supply.

[@dhpbear2]

I'm guessing that this is a class-A amp, due to the massive power supply for a mere 70 watts output. A class-A amp consumes the most power when it's idling!

[@mikepxg6406]

Enjoying this one.

[@Operation-Underground]

I own a few NEC units including and A11, A10,A7 and several M50 mono amps I acquireed them several years back. I'm planning to have them all overhauled. I just thought they were nicely built units and kept picking up NEC stuff as I came across it before gear hoarding started driving prices through the roof.

[@PilotInCommand777]

I had the same issue, (camera in video mode stopping intermittently) with a Canon eos 90D and it turned out to be the counterfeit memory cards I purchased. They were supposed to be actual Samsung cards but turned out to be fakes. Or maybe your memory card isn't fast enough for the camera? Maybe???

[@MrJohnBos]

I'd get a Sony ZV-1 camera. They are inexpensive (~$700) and can record in 4K. Hard to beat for the money. DJI makes some interesting cameras that are very small.

[@deviantmultimedia9497]

That's what he's using. They have an overheating problem

[@stephensams709]

I would say that the 70 watts per channel is probably extremely conservative considering the reserve it has on tap. I've got to admit, I've never seen or heard of this unit, but I do like NEC products.

[@mdzacharias]

What about the "power amp level" adjustments on the front panel? Had to ask... not a common feature.

[@xraytonyb]

If you look at the controls, one is marked "Integrated / Separated (CD)" It works kind of like the preamp out/main amp in connections. The volume knob controls the level of the signal coming out of the flat amp and the power amp level knobs control the input level for the power amp. I think the idea was that you could plug a CD player (very new at that time) into the CD/Direct input on the back of the amp and use the level controls to adjust the volume, minimizing the audio path. I think that's why the power amp has a higher gain than other amps of the time.

[@marcvdfv8431]

Tony, why didn't you put the filmcaps (at 52 minutes) on the other (under) side of the board?

[@xraytonyb]

There wasn't much space behind the back of the board and the caps I used were automotive grade and can withstand higher temperatures with no adverse effects.

[@nabman_]

Hi Tony, unless it's a settings item, I wonder why would a camera limit the time if there's enough storage. Maybe it's a malfunction? And the overheating is not normal either. Looks like its processor is overworking. Does the setting allow to increase the buffet size? Can you add RAM? Maybe use a faster storage card? I hate working with video too. 🙂

[@UK_Lemons]

Of course one must put up barriers to keep ones self intact. RIP NP.

[@FaintSignals]

I was going to suggest going back to your old way, the old videos were perfectly expository, at least for me.

[@ScottGrammer]

I'll dig through my manuals and see if I have a manual for that model. If I do, I'll get you a copy. I doubt I have one, though, as I rarely see NEC's.

[@xraytonyb]

In the second half, I get the full manual. Thanks for the offer, though!

[@AndrewTa530]

Thanks for using a bunch of words to say nothing 😂

[@ScottGrammer]

@@AndrewTa530 Who pissed in your Wheaties this morning?

[@ScottGrammer]

@@xraytonyb NO problem. Someone didn't seem to approve of my offer, but they'll be strong.

[@xraytonyb]

That's why it's called solder 'n chat.

[@mfr58]

I had an old Sony digital camera that i really liked, but it too had thermal issues....it didn't like cold weather and shut off if I took it out in winter....

[@jamesrobinson9176]

Holllyweird is responsible for the way your camera functions. They're responsible for the 10 minute length of recording time. Well, them + the feds...

[@adeel6674]

hi tony . every board has its own separate shunt type regulators . every board has its separate supply form transformer. driver 's board in its middle is shunt regulator not drivers. i am very interested to see output transistors part number . if you find service manual plz upload to an easy website not hifiengine they don't allow to download without registeration and they don't register new ones so useless to upload there for me . thanks

[@xraytonyb]

Very strange choice of circuit. It uses 3 series-strung zener diodes and a JFET current source to make a 15 volt supply out of a 70 volt source. Needless to say, those JFET's run pretty warm. Every place on the board where they are mounted, you can see where the board has darkened from the heat.

[@adeel6674]

@@xraytonyb yess i don't understand why they used those shunt regulators . its true its very hot all shunt regulators heat sinks are so hot that i can't touch them . sir you can guide why nec using this method . nec a-10 reserve 1 and a-11 used three transformers small transformer is to supply power to flat , equilizer board and driver board of main amp. nec a-10 reserve 1 use very high ft transistors of 90mhz and it sounds colourless .

[@sebastian_harnisch]

HP/Agilent instruments from the late 70s/80s are optimized for serviceability. So engineers knew how to do it back in the day, but some simply did not care enough or had the time/budget, I guess. This is what I like about my simple (non-high end) Technics SU-VX 700 from the early nineties. Very modular, very easy to work on. Just a transformer, a heat sink and a couple of PCBs with connectors and a ton of screws (for the most part), but very few wires. (Of course there are other things to criticize…)

[@billsmith5166]

I'm guessing your Sony is time limited on that resolution. They have a tendency to overheat.

[@xraytonyb]

Yes, it is. If the display is folded against the camera, it heats up faster. If I fold it out, it will run about twice as long. Either way, it doesn't work for longer clips.

[@sebastian_harnisch]

Maybe a fan would help a bit. 😅

[@billsmith5166]

@@sebastian_harnisch I should have waited for a bit more before I posted. He solved his problem about halfway through.

[@arcsound]

You are fearless, wading into that hot, sticky mess of an amp without schematics and/or service docs! Hat off, Tony. PS- what about using your phone to film "the show"? I'm sure there is a downside, otherwise you'd already being doing it...

[@arcsound]

Speaking of service docs, could you please speak to the modern trend of manufacturers not making available service manuals or even schematics for their equipment? In the 70's, every major player provided (made available) detailed information; schematics, interconnection diagrams, parts lists, board layout, and calibration instructions. These days, it seems companies don't even supply their dealers with tech info. How are we going to maintain this equipment in the future, when there is no factory support? Future = 2-3 years...typically.

[@isoguy.]

I believe the only answer is that they want you to buy a new one rather than enable people to fix their own electronics. Companies have tried to sue people who shown viewers how to fix their electronic items on KZbin or other similar platforms; this is a disgraceful practice and not at all environmentally friendly, though many of these companies purports green credentials.

[@Poppinwheeeeellllllieeeeez]

Trevor over on Trevors Bench channel did a 80s HK with those green caps and a lot were bad.

[@t1d100]

👍👍👍👍👍

[@roroseppel2077]

The new camera cleaned the inside of the amp !

[@jdmccorful]

Good chat! Interesting directions; looking forward to the rest of this adventure. Thanks!

[@hullinstruments]

My apologies this is off topic..... Was rewatching your analog multimeter video a few days ago..... I've been hoping for years someone would build a modern analog multimeter with built-in ESR tester. And possibly other modern multimeter/lcr functions. Iv seen them available online but none of them will ship to the USA. I think it would be a very useful device. Again my apologies for this being off topic

[@Dutch-linux]

I love the count in the muppets !!!!

[@user-mv5bu2kk8b]

Help Kp this good man get a camera and click on the thumbs up

[@robertyoungmcdonald]

regards, u called that a Reciver receiver um its an Amp ?

[@xraytonyb]

You mean I only misspoke once in this video?? Thank you for the compliment! ☺

[@kevkabluebird1032]

At some markets, DSLRs and Non-Camcorders are indeed "limited" by design. It's not overheating, no? The sensor gets hot while recording. My BlackMagic has a build-in fan to mitigate the heat during recording. /edit: Oh well, you just spoke about overheating later in the video :D Nevermind.

[@mixolydian2010]

My camera only records up to 28 minutes due to overheating safety cutoff.

[@fr6885]

Lot of heat all over these boards. Brown sections on all of them.

[@FaintSignals]

Johnny Paycheck has a song "A-11" the refrain goes, "please don't play A-11." Obviously, Tony never heard it 😁

[@xraytonyb]

I don't intend to play it again, but I may take this amp and shove it! ;)=)

[@Dutch-linux]

I do this for a living... but i never get the US. models they are different then what we got in europe

[@williambock1821]

I don’t have the schematic or anything I just yell at the screen all the time anyway. No words. Just yelling. 😊

[@PossibleAudio]

@1:19:00 HAHAHA!!!!!

[@mitkothemacedonian]

All 4558 opamps must go. They are not hifi by today's standards, their slew rate is way too low. At least put them in 8-pin dip sockets so they can be swapped.

[@xraytonyb]

I thought the same. What a strange choice for something directly inserted in the audio path.

[@mitkothemacedonian]

@@xraytonyb it was just good enough in the 80's, or at least a bit better than the LM741 😁. Texas Instruments doesn't sell snake-oil, so whatever one gets from them, he gets his money's worth, especially with the LM4562 for bipolar input opamps and OPA2134pa for jfet ones, where high input impedance and low DC offset are needed.

[@JoeGoesXtreme]

Hi Tony, I think that those boards are not the same. One is the Equallizer board, and the othe rone is the Flat amplifier. I believe that is similar topology to that for the Sansui AU-919 or the BA-F1. Is there a MC phono input in this unit?. If so, the equalizer board probably brings the MC phono signal up to the same level as the output for the MM phono. These phono signals would then be comparable in amplitude to the tape/aux signal level, which can then be applied to to the Flat amplifier prior to the power amplifier. I think that is not a cheap amplifier, but rather, it is like you suggested, NEC's version of the Sansui BA-F1 or the AU-X1, so recaping it and bring it to its best is very much worth the effort.

[@xraytonyb]

Strangely enough, the circuits are almost identical, with only a few component values being different, in order to set the different gain of the voltage amplifiers. On the EQ board, they also inserted the RIAA EQ filter into the feedback servo circuit. Other than that, mostly the same.

[@SeanBZA]

You want heavier Hitachi HMA 7500 and the whole HMA series of class A amplifiers. 2kW of power in idle.........

[@mikebond6328]

The manual alone is out of my budget range.

[@stphinkle]

Maybe you should do a repair video in which you take apart the malfunctioning camera! I wondered if a heat sink is not right, if a thermal sensor is going bad in the camera, if the software is faulty, or what. You might also see if it is still under warranty, and if so file a claim with the warranty. A Camera should not be shutting off every five minutes.

[@sebastian_harnisch]

Unfortunately many (photo) cameras have this great feature. There might be a fault, but most likely it is just engineered that way. I saw a suggestion that there was a setting to allow higher temperatures. But other than a software/firmware fix by the manufacturer you're likely stuck with the problem.

[@Dutch-linux]

Tony what is your email address then i can give you the link to the service manual for it .... or any other way maybe facebook ??? yt wont let me post it.

[@xraytonyb]

I have a manual now, but Thanks for the offer! You'll see it in the second half. The video was just too big to upload all at once.