I was one of those kids that took everything apart to see how it works. 60 years later I still do. Only difference now is I put them back together!
Join me as I repair vintage audio equipment, test equipment and other electrical/electronic items. I'll share my process, my troubleshooting philosophy, how to read schematic diagrams and test electronic components.
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Amazes me when I see these things being taken seriously overseas. In the UK they are nothing more than cheapo House-brand units sold by Richer Sounds, a discount hifi/AV retailer. They generally sound pretty good but under the skin they're the same cheap Chinese junk sold by all the sheds.
Maybe that's part of the appeal, that they're not that common here. Years ago there was a beer that wasn't nationally distributed. Anytime someone went to a part of the country where it was available, they brought some back and everyone clamored for it. Now that it's available nationwide we all realized it was swill. 😆
Hello Ray, nice and useful video once again!. I hope there is a way to figure out what is wrong with the display. Most of them have an epoxy blob covering a chip that decodes the signals and applies all the signals to drive the LCD. If that chip fails, there is not much you can do. The back light is usually driven separately, and it does not involve the said chip so the fact that there is back-light does not necessarily mean that the driver chip is receiving power. Most likely you already knew and tried this, but if not, it would be my two cents.
Appreciate the input, Joe! I suspect it is the processor. I had voltage to it, and pulses as well. No idea what pins do what, as there's no part number on the blob. I was disappointed in the outcome, but that's just the way it is with some items. McIntosh has service literature and parts going back decades. Other manufacturers,well, not so much.
@@raygianelli3612 I know what you mean! I'm retired as tech but, I will say it was easier back in the day before surface mount came into play. I have my own workshop at home but, I do it for fun. I guess it's in the blood! I do enjoy your videos since you work on the good old systems! Keep them coming Ray!!! Be well! 🙂
@@alfonsoincorvaia2595 Thanks Alfonso! Some guys build birdhouses, some of us repair old stereos. Fortunately, the birds around here manage to find their own housing. 😁
Nice to see another video from you. Would have loved to see the smd installation. I sold many of those. I think that player has a dimmer, on off function. It’s been a while since I had one.
Thanks Andy! Bummed I couldn't get the display working, but I'm starting to think this unit was subjected to a power surge, possibly lightning induced. The owner is a snowbird, and this unit was in his Florida home. When he came down he found it wasn't working.
I've had a 740C for over a decade. I've never had to repair any device more than this unit. Those main filter caps are 'proprietary' (I.e. as cheaply made as possible). A transistor and some caps in the servo always go. And the worst being the connectors and traces in the front panel get intermittent open circuits. They are great sounding players when working but they tend to come back like boomerangs with another issue. Scrap it!
In C640v2 they have sandwiched two no name 85°C caps between bare, non- heatsinked 78/7915 regs running in excess of 50°C with foreseeable consequences. Planned obsolescence. All tactile switches had to be replaced as well, along with the drawer belt.
Wow, I had no experience with Cambridge Audio products. I thought they had a good reputation. Between your post and the one before it I'm not so sure now, at least in the CD player realm.
I have experienced LCD that had the various layers de-laiminate when heated(OLD radio shack portable computer 1980's stuff. When left on automobile dashboard in the hot Florida sunshine). It went totally black.
12:19 harmony 650? dunno why they had to stop making them. it's going to suck when they take down the server and they can't be programmed anymore but until then, i love mine.
Right? I bought that one on Amazon for about $25. When I looked for another they had stopped making them and they were asking 10 times that amount! My previous smartphone, an LG V20, had an awesome IR remote app that came with it.
Moist environments are not good for electronics, it looks like this amp was stored or used in a garage from the looks of that corrosion and the power transformer was rusty looking.
Wil, there's a limited number of instances where this will work. The amp has to be full complementary and have no protection relay. for amps with a relay, you can just clip onto an emitter resistor in lieu of the speaker jack.
The power supply is really different. I worked on a similar one, and the power supply was a bear to troubleshoot due to its design... or just my lack of understanding it. 😆
Hi Ray great job as always👍 never seen meters corroded like this 🤔 must have been in a very humid environment 🤔 or they were cooling it with water 😂. Nice day 🙂Tom
Hi Tom! Humidity is just brutal here. I run before sunrise to avoid the heat, but the humidity can reach up to 100%. I didn't know you can have 100% humidity without rain, but apparently you can.
Humidity + Nicotine are the usual culprits in this case. I also woldn't be surprised to find out that, at some point, the face of that amplifier was drenched in water.
Old vintage stuff like that is hard to find .... I was raised on tube type stuff then solid state . Me , myself I don't really need the meters to achieve a balanced sound .... Great job on that diagnosis ..
A friend told me that some guys are just in love with meters. Half the time I'm listening to music my eyes are closed, so it's not a big deal to me either. 😁
Thanks for sharing ,but if you’re getting distortion on the peaks would that mean you’re driving the finals to hard or is there a fault in the amp it self ??
If it is equally distributed between the positive and negative halves of the sine wave AND is in excess of the amp's rated output, then you are driving it too hard. If, however, it is pronounced on only half of the sine wave or exhibits at below rated output, then it would indicate a problem.
Ray, check the pnp input differentials , the blue caps on the amp driver board, and the pnp devices in the phono preamp and line stage. I do not remember the pnp device numbers . Also cracked solder joints in the PS on the dropping resistors.
Great repair and good to save it from jaws of the recycle center. I wish I had the $ to send you my dying NAD 9060 6 channel amp to completely update. I'm now getting hum and distortion in several channels. To save it I will have to recap and replace any other failing/failed parts. This is likely going to be a major task. Luckily, I have many great electronic techs like yourself to give me inspiration and guidance. All the best to you and yours, Kevin
Kevin, while blanket recapping is usually not advised, the exception would be NAD gear. Certain generations used cheap electrolytic capacitors. I have an NAD 1300 preamp, and all the capacitors in it were measurably defective, with the exception of 4 Rubicon caps around the phono stage. If you have a way to check a few this well might be the problem.
@@raygianelli3612 Thanks Ray! Do you have a suggestion for an ESR tester? And, a transistor tester. I also have a pair of NAD 214 amps and dozens of arc welding power supply boards to repair. Yeah, I'm buried in work and have little skill in the repairs. But, I hope to get a handle on all of it someday.
Thanks Ray! Well done, as always! The process is the most interesting thing of all. Somebody needs to write a book like "The Inner Game of Electronic Repair"...
A lot of work with this Marantz tuner, but with a good result. In this situation why not suspect that the local oscillator is detuned? Someone could have manipulated it. Or a problem with the J-FET RF input amplifier?
Good job as usual Ray. You explain your diagnostics and trouble shooting very well. Look forward to more. I also have realized that accumulation occurs much easier than decumulation 😉, but I’m getting it done…moving soon too. Good luck with the strike…CWAStrong!
Thanks for the shout out. Moving is for sure a pain, but it's time. Hopefully the strike doesn't drag out too long. Many of the younger folks can't afford to miss one paycheck, let alone more.
Thanks! There was a bar here named Mr. G's. Had a huge stage and a great house sound system. Gigged there several times, what a great place. Sadly no longer open.
Ugh, me too. I used to joke about having a "cleansing fire" instead. Now I pray I never have a house fire; I've made that joke so many times on line the insurance company is bound to find it. 😁 I had an elementary school teacher on Long Island named Mrs. Van Dusen. That I still remember her says volumes.
Glad you’re back online. I seriously doubt it will be a long strike nobody can afford a strike any more. I survived three strikes. Metro Atlanta is a good area. Climate is reasonable year round. Housing is no where as high as the area you live in.
Another awesome one, Ray :- ) I'm sure this will be helpful in the future when i have one of mine act up or am checking out something for someone.. the little bits of info are super valuable to us fairly new to troubleshooting. I'm happy things are well with you and you are back. Rock on dude ! I have some light hum in my Nikko NR-1415 that needs to be addressed at some point (probably over the cold season when i'm indoors more!) and all these little bits of info help!
I have a 2246 doing the same thing. Clicks and the fan jumps when trying to power up. Where do i find the schematics so i can try to troubleshoot mine?
Glad to see you back! For future reference, the 150 Ohm resistor in series with that 1318 is also a common failure, and the blue (sometimes white) Sanyo coupling caps are notorious. In the SX-828 they cause big problems in the tone circuit but I think on the 850 they used Elna for that.
I hope your strike is a short one. I was on strike against Illinois Bell for a week and a half in 1983, but I was young and still living at home, so it was just an extended vacation. I can't see managers taking techs spots nowadays, especially in a CO environment or working on customer network equipment, as, very few, if any, know the requirements to even access the info needed to troubleshoot, resolve or install new new circuits or equipment. It's different to see how Pioneer powered some of the input amplification with a separate power supply, as most every amp powers that part with the same rail as the rest of the amp section, so I could see how that would throw troubleshooting the DC offset for a loop.
