McIntosh C31V Volume Control Issue
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- เผยแพร่เมื่อ 18 ก.พ. 2024
- This video outlines the troubleshooting steps taken to repair an unresponsive volume control. Unlike vintage analog volume controls, this one is electronic.
#electronic #electronicrepair #vintagestereo #vintageaudio
Nice to see you again, Ray. We all missed you.
Thanks for that sentiment! But I'm not all the way back yet, still got a ton of stuff to catch up on. For instance, I'm sure there's a floor in my office. But I haven't seen it in a while. 😶
Omg😮! Ray was kind enough to help me with a project and I've been in that garage. To see any bare shelf space would appear to border somewhere between the miraculous and an atom bomb.😂. Congrats, you must have sold a ton!
Thanks Keith. Some I was storing for someone else, and he hauled some away. I sold some stuff, and gave some away. Also disposed of some things that were just useless.
Ray's back ... and swimming with the big McIntosh fish, too!
Yep, IC sockets, particularly the kind with the side spring contacts can be a problem. The explanation I read is that over time the pin of the chip and the leaf spring contact in the socket relax to the point of almost no pressure, dust and gunk gets in there and eventually the contact becomes intermittent. Taking the chip out and putting it back in usually pushes the gunk aside and remakes the contact. The advice was to flex the IC pins out very slightly before re-inserting to restore contact pressure.
Welcome back!
Yep, you saved me some typing !
Back in the beginning.. McIntosh used removable output cards in their amps , my experience was the cards fit was loose , I made a shim from package plastic that pushes the card into the pins , works great now..
We had a lot of socket issues in industrial electronics. Mostly from dirt and vibration. I was also taught if you remove a chip from a socket 10 times, replace the socket. Probably not going to happen in home audio equipment but it did on industrial electronics.
I considered replacing the socket. But I figured it will work for another few decades, after which we'll be getting our music through a neural interface. 😝
Good advise ! Thats why i am using tulip IC sockets !
Due to this video, I learned what you already knew, Roro. Not all IC sockets are created equal!
I haven't reached out to Sunfire. Don't even know if they're still in business! Will have to look into it further. Sure with they'd put in more substantial pots than what they did. You know.... something that would hold up for a long time. BTW the lamps I bought from you were easy to put in on the sansui 9090db. Thanks again! It gets fired up now and then. Sure is a fine specimen. So MUCH Power! Would list it but nobody's got any money to buy it they're struggling just to make ends meet and put gas in their cars to get to work! Have a great one and we'll talk again soon!
Thank you for sharing the troubleshooting on this.
Thanks. As always, it's a learning experience. Or a relearning experience. I'd just never seen a socket this bad before.
Need a volume IC for a McIntosh? 🤭
Hello RAY, nice to see you, this emptying is waiting for me too, I can't go through the warehouse without taking out boxes.
Oxidation of sockets and connectors is a very unpleasant problem that has different intensity depending on the environment in which the device is located. A few years ago I dealt with something similar - it was not the volume setting, but the input for the magnetic sensor. The customer bought a new device and after half a year random failures of this sensor began, it could not be measured, because after the intervention everything worked normally, there was no problem when measuring continuity. The entire control board was replaced and the problem disappeared, as it turned out later it disappeared for half a year, after the same period of time the problem returned - random sensor failures again. Since there was never a problem with this sensor in older devices and it was repeated here at regular intervals, I started to find out what has changed in the circuit of the new machine - connectors - respectively the surface treatment of the contacts, due to the ban on the use of lead compounds. When measuring the continuity, this problem was not discovered, I thought about why and the signal level came to mind - when I measured the continuity, the measured circuit was functional, because the multimeter had a significantly higher voltage and current that it applied to the circuit. I broke the circuit in another place, measured the current flowing through the circuit - under normal circumstances 50uA and suddenly nothing, I moved the connector and the circuit was functional again. First, I cleaned all the connectors with Kontakt 60 to remove oxidation, then sprayed them with Kontakt WL rinse agent and then treated them with Kontakt Gold - the problem disappeared and the defect no longer appeared.
I wish you a beautiful day and I'm looking forward to more videos of your wonderfully tidy garage 🙂 Tom
Nice to hear from you, Tom!
I used to work for a water and sewer utility as an instrument tech. Stuff for measuring flow, temperature, pressure etc. A lot of damp, sometimes nasty environments. I dealt with connection issues, but some of the equipment was extremely well built, and used heavy conformal coatings on the circuit boards. Still, connection issues were not uncommon. We cleaned and treated connections as best we could, and for the most part kept the demons at bay.
The garage is coming along. Gotta keep up the momentum though!
@@raygianelli3612 Well, it had to be something to keep everything working, in my case it wasn't exactly a laboratory environment either - the industrial kitchen and the equipment was a very smart Convektomat - so grease, steam, moisture and temperatures in the range of 5°C (when the heating in the kitchen was closed kept in antifreeze temperature in winter) up to 300°C, i.e. the maximum working temperature.
Some sockets for IO are bad from the factory, especially those that have contact on only one side directly against the plastic case without a counter contact.
@@Edisson. Wow, that's some temperature range!
Great video Ray! I hope you are feeling better!!!!🙂
Thank you, back to 100%!
@@raygianelli3612 Thank you Ray!!!
I'm experiencing issues with the very small pot volume controls on a couple of my carver Sunfire subs. They are very very easy to turn. I've used the proper sprays to clean and lube them and still have dead spots when trying to adjust volume. One of them (amps) was even sent in to a highly recommended electronic repair facility back east. I believe it was called E B C electronics or something close. I wish carver had used higher grade/quality pots. One of the subs really only works when the pot is turned to full. Not ideal.....
Now that's interesting. I was working on a Definitive Technology sub, and I called to see if service literature was available. Gentleman I spoke with said I didn't need service literature, he'd send me a replacement board at no charge. He said the volume pot fails open. I checked the one on my bench. Sure enough, pot was bad.
I guess the extreme vibration takes a toll on them.
There are quality IC sockets and there is cheap chinesium. Lots of manufacturers trash out here and just a few manufacturers of quality. I usually used Cambion
I prefer soldered IC's. Not that solder joints can't fail, but they're more dependable, IMHO than sockets.
@@raygianelli3612 They wouldn't agree with you at Tektronix, they also put transistors in the sockets and each pin of the socket is a separate unit mounted on the PCB 🤪
@@Edisson. Maybe they used better sockets, 😁
From Tek wiki Texas Instruments made some bad IC sockets back in late 1970's. The TI C-95 model of socket is known to be a problem. The design was too fragile. Replacement with better quality socket was recommended. Might be a possibility.
I believe the bad connection is called terminal fretting. In the automotive biz we get tons of problems with poor connections. The fix is to use dielectric lube on the terminals. Not dielectric grease, that does not last very long.
Hmm, I tried to find dielectric lube, but it brings up dielectric grease. What the stuff you're referring to, Scrappy?
Search Nye lubricants, they make a ton of lubes and greases for terminals and connections. The stuff we use at work is sold by Delco as dielectric lubricant, but there are different formulas. I've been experimenting with it on audio switches, the ones where the contacts slide. Have had no problems in 2 years. @@raygianelli3612
@@raygianelli3612 Silicone paste for contacts, used mainly in automotive and/or Wago clamps to protect against moisture, I have it at home, but I wouldn't think of putting it in the audio.
Silicone paste is not the same as dielectric lube.@@Edisson.
@@scrappy7571 That's possible, it's sold here under this trade name - I have it in a drawer next to me
Great video Ray. My 1999 Mazda fuse/relay box gave me the same trouble with the air conditioner, bad connections in the relay socket. I do have one question for you. Why does the bench clock say three forty, and the clock on the other side of the garage says ten after two? 😂😂
The other side of the garage is a different multiverse. 😜
😂 this is the so-called service space-time - with the correct setting, the repair is finished before it started, and therefore more can be done 🤣
@@raygianelli3612 😂
@@Edisson. LOL! If only more of them worked like that!
So why isn’t it an ORN gate?
The hybrid ones are HORN gates 😁
Gianelli as Italian name?
It was originally Giacoponello. My father's people came from Sicily.
I don't know how we wound up as Gianelli.
@@raygianelli3612 Amazing, like Frank Zappa. Greetings and a strong hug from Italy big Ray
Hi Ray ! forgive my ignorance but is this the same McIntosh company that made much loved Valve amps please? also it has to be the ugliest cheap and nasty looking piece of audio equipment I have ever seen ! Don't want to upset any one its just my opinion on aesthetics does it sound nice ?......cheers.
Same McIntosh. I need to bring it in the house and connect it to a better power amp and speakers before I can comment on the sound quality.