I heard that you should slowly raise the voltage on a vintage stereo if you have not connected it to 120v in a long time. Something about damaging the capacitors. Anyone familiar with this?
Slowly raising voltage for old stereos, because of capacitors?
- Thread starter daves66nova
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Why? A blanket statement like that will get you in deep doodoo real quick.
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I would check them before replacing them, depending on age I’d likely replace any electrolytic capacitors regardless though.
It's nonsense. Been in the electronics field for over 35 years and never heard of that. Power supplies on vintage equipment are simple. A dried out open capacitor from old age will cause more ripple riding on the DC which often can be heard as a hum. I have many vintage stereo amps/ receivers and never did what you mentioned. Only way you can quickly damage capacitors is exceeding their rated maximum operating voltage.
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If they are bad.
Just make sure the fuse is in place and the proper size, not bypassed or a ridiculously large amp value used. if its been in storage that long it might be broken.
If the caps have a major problem, they usually short which will take out the fuse. Ramping up slow will not prevent this problem. More likely the fluid in the cap dries out and you lose capacitance value whish as Lubener will cause more 120Hz hum in the circuit or not allow it to work at all.
If the caps have a major problem, they usually short which will take out the fuse. Ramping up slow will not prevent this problem. More likely the fluid in the cap dries out and you lose capacitance value whish as Lubener will cause more 120Hz hum in the circuit or not allow it to work at all.
We must live in different universes! Seen this many times in tube guitar amps and old ham equipment. SOP to replace these
I have a vintage 35 watt per channel, Pioneer receiver that has one dead channel. It always sounded really good and it is physically in excellent shape. I'd like to get it going again.
I have as a hobby old radios. Probably over 150 of them that I repair and display. Most are tube but have germanium transistor collection too. Bad caps hum on AC and weak sound on transistor radios is the capacitors drying out. Replace the power supply ones and use a scope on the weak sound systems to pinpoint the problem. Transistors are very rarely the problem.
Great receiver! In my experience with mine, it wasn’t the caps, but the transistors, their leads corrode over time. Replaced them, and all is good. That old analog stuff sounds great
Replacing electrolytic capacitors in vintage electronic gear such as stereos and ham radio equipment has become a normal way of life for most of us in the electronics hobby world. In many cases the aged electrolytic capacitors have significantly aged and degraded (or worse yet leaked) and can no longer be counted on to properly do their job. This seems to be especially true for those capacitors in high voltage circuits.
Here is an article on aging electrolytic capacitors. The authors of this article are in the business of restoring audio amplifiers and ham radio equipment.
Here is an article on aging electrolytic capacitors. The authors of this article are in the business of restoring audio amplifiers and ham radio equipment.
Not denying caps dry up and open with age. To take precautions in powering up, no. What damage is going to take place especially with tubes? The caps were bad before even powering up after a long downtime. More than likely you will hear a lot of hum from the ripple riding on the DC out of a power supply.
While I'm not smart enough to follow the above conversation, I do own a Marantz 2330B for my turntable and tape deck.
I blew it up within 10 seconds after it had been gone through and all caps and circuits had been replaced properly. Gotta have an "output" selected before you turn up these things, kids. Otherwise, there is nowhere for the caps to push the power, and they blow.
I blew it up within 10 seconds after it had been gone through and all caps and circuits had been replaced properly. Gotta have an "output" selected before you turn up these things, kids. Otherwise, there is nowhere for the caps to push the power, and they blow.
35 years ago I had already been working in the electronics field for 15 years, and I've heard of it, and done it.
It was more of a thing before the '80s and transistors.
While you can ramp up the voltage with a variac on gear with solid state diodes, with tubes it's better to clip on an adjustable supply to the cap in question.
Then you don't have to play with warming up the rectifier filament; and monitor the current, which will be primarily the cap current since all filaments are cold.
Don't have a variac? Put a (incandescent) light bulb in series with the line. Also gives a visual indication of the current.
Reducing Failure Risk with Capacitor Reforming - Quad Plus
Spare capacitors are not enough to ensure quick recovery in the event of a failure. Periodic capacitor reforming allows for immediate use and quick recovery.
www.quadplus.com
Same here, have a vintage Sansui receiver that hasn't been used in the last 40 yrs, the balance potentiometer was starting to go, looking for a repair shop that specializes in vintage audio.
even more so with tube electronics.
Electrical engineer here, and I've been restoring vintage tube electronics for decades, ranging from antique tube radios to guitar amplifiers, and amateur radio gear. Electrolytic capacitors do degrade if they are discharged for a long time, and they don't always fail open. They can look like a short circuit if the aluminum oxide dielectric degrades, and there is a very real danger of damaging rectifier tubes or burning out transformer secondaries, this does happen. I don't subscribe to the notion that all electrolytics must be replaced without question, but I would never just plug in some tube gear and turn it on.
