Ecaps don't dry out from being (over-) stored.
Drying out only happens with long time usage at elevated temperature.
Long time storage does increase leakage current, though.
Reason is an electrochemical de-forming process when the cap is not charged.
When in use the caps are constantly re-formed.
Ecap manufactures recommend re-forming at rated voltage using a 1k current limiting series resistor for at least 1 hour, when stored longer than 2 years.
I prefer a more gentle method using a larger series resistor of 10k/25W while monitoring the voltage drop across the resistor.
When the resistor voltage drops below 10V re-forming was successful. This can take several hours.
If the resistor voltage stays high or the cap gets hot, I would increase the resistor value.
The larger the series resistor the longer it may take to bring down the leakage current to 1mA.
With this method it is not necessary to bring up the voltage slowly, as this is accomplished automatically by the decreasing voltage drop across the resistor.
When there's no suitable HV source available, re-forming can be done in the amp using an LBL (lamp bulb limiter) before the amp with a low wattage (e.g. 20W) incandescent lamp.
Drying out only happens with long time usage at elevated temperature.
Long time storage does increase leakage current, though.
Reason is an electrochemical de-forming process when the cap is not charged.
When in use the caps are constantly re-formed.
Ecap manufactures recommend re-forming at rated voltage using a 1k current limiting series resistor for at least 1 hour, when stored longer than 2 years.
I prefer a more gentle method using a larger series resistor of 10k/25W while monitoring the voltage drop across the resistor.
When the resistor voltage drops below 10V re-forming was successful. This can take several hours.
If the resistor voltage stays high or the cap gets hot, I would increase the resistor value.
The larger the series resistor the longer it may take to bring down the leakage current to 1mA.
With this method it is not necessary to bring up the voltage slowly, as this is accomplished automatically by the decreasing voltage drop across the resistor.
When there's no suitable HV source available, re-forming can be done in the amp using an LBL (lamp bulb limiter) before the amp with a low wattage (e.g. 20W) incandescent lamp.
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yes, i do this on computer grade caps, i once reformed a pair 56kufd/63wvdc Nichicon caps, they reformed to around 75vdc and the leakage current was well below 1mA and was still decreasing when is stopped...
the ESR of the ecaps also contribute to heating, not just ambient temperature...that is why ecaps are almost always slimmer than they are taller...
In my case, I don't have a resistor or circuit to charge slowly and I would need to remove all the electrolytic capacitors from all the boards of all my electronic devices, very complex.
There is no study or recommendation from manufacturers on the time (minutes, hours) required for the procedure with electrolytic capacitors that are already soldered on the PCB of electronic devices to turn on all 220v electronic devices (in my case) to avoid high capacitor leakage current electrolytics with electronic devices that remain stored for long periods?
There is no study or recommendation from manufacturers on the time (minutes, hours) required for the procedure with electrolytic capacitors that are already soldered on the PCB of electronic devices to turn on all 220v electronic devices (in my case) to avoid high capacitor leakage current electrolytics with electronic devices that remain stored for long periods?
Yes, ESR times ripple current squared causes an internal temperature rise adding to ambient temperature.
This is a self-accelerating process as increased temperature facilitates dry-out and ESR increase.
While Re-forming often helps with increased leakage current by repairing the aluminum oxide dielectric, it can't cure the consequences of dry-out being increased ESR and loss of capacitance.
If the caps are not too old, it should suffice to turn on the equipment for an hour at least every 2 years.
I have electronic devices from the early 90s (snes, crt tv) electronic devices from the early 2000s (ps2 slim, crt tv) and recent electronic devices all work fine and storage
I have electronic devices from the early 90s (snes, crt tv) electronic devices from the early 2000s (ps2 slim, crt tv) and recent electronic devices all work fine and storage
In this case, how long should the devices be kept on to repair all the electrolytic capacitors and avoid failures due to disuse? What do the manufacturers say?
In this case, how long should the devices be kept on to repair all the electrolytic capacitors and avoid failures due to disuse? What do the manufacturers say?
use a
Use a 25W filament bulb in series on first turn-on, never go straight into Mains.
No, the full opposite: it is WAY more likely to fail if left fully unpowered for many years.
Short answer: NO, you will not turn the clock back, what has dried up has dried up, period.
Besides, it´s too late, you should have done in once year since the 90´s.
Why didn´t you?
Not to be impolite but you are being incredibly blunt.
You have been answered many times that there is no REPAIR taking place, at all.
You are not asking for answers (which you clearly don´t like) but for confirmation on some weird preconceived idea you have.
Namely: that 30 years of neglect (30+ years in storage, never ever turned ON) can be reversed by some simple and effective action (turning them ON today, for 1 hour, straight intoMains with no limiting or protection).
Bonus points for it happening in subtropical Brazil, were I would expect, say, 30C average insted of , say, 10C or so as in great parts of US, Canada or Northern Europe.
The higher the average temperature, the faster the deterioration.
Manufacturers say nothing of the kind because it does not happen that way.
You have already asked and been nswered the exact same question some 5-6 times.
It is getting boring.
Nobody will give you the answer you expect because it does not work that way.
It is equivalent to say (and chemically quite related) to: "I have left my car untouched (specially never washed) for 30 years in a chicken coop barn, it´s rusted all over the place, for how long must I leave it in a dry clean place for all rust to go away?"
You may slow down further rusting, but what´s already there will stay, no magic solutions for that.
I'm not saying that turning on all electronic devices regularly will restore all electrolytic capacitors, what I want is to find out if 1 hour (60 minutes) is enough or not to prevent electrolytic capacitors from failing due to disuse? What do the manufacturers say? Do you have any studies?
I have electronic devices from the early 90s and early 2000s, they all work normally and they use electrolytic capacitors
I repeat: electrolytic capacitors inside electronic devices fail if left unused for a long time or is it a myth?
and I didn't keep the device turned off for 30 years, I bought it from a seller, after that I decided to be careful
I have electronic devices from the early 90s and early 2000s, they all work normally and they use electrolytic capacitors
I repeat: electrolytic capacitors inside electronic devices fail if left unused for a long time or is it a myth?
and I didn't keep the device turned off for 30 years, I bought it from a seller, after that I decided to be careful
20-30 years is not unreasonable to expect for the minimum lifetime for original, specified quality E-caps, as fitted to respected brand audio equipment and used in standard domestic conditions. The climate you live in though, will have a large effect on lifetime and you may get 40 years of gentle, occasional use where summer temperatures don't go much over 20C but as little as 20 years where it's 30C+ for much of the day. Note that storage temperatures and close-fitting display shelves contribute to heating and drying out caps too.
The quality of caps in cheap, off-brand audio equipment is also suspect. Some caps are actually total fakes with only a tiny cap inside a big can, so don't assume that all components, particularly the expensive ones, are genuine or OEM spec. At around 20 years of age, regardless of usage, I generally consider replacing or at least asking the owner rather than tinker with trying to reform cheap/suspect caps because that won't save dried-out caps that will become a serious problem regardless of how much re-forming is attempted. In any case, I still usually power up other people's gear and any seldom-used equipment with a lightbulb limiter (AKA dim-bulb tester or DBT) fitted. If properly and safely constructed, that's a simple, easily fitted device in the power line and experience with using one can tell you a lot about the condition of your power supply and amplifiers. There are plenty of U-tube videos for making them too.
Short version - re-forming is not a universal fix for dying caps.
The quality of caps in cheap, off-brand audio equipment is also suspect. Some caps are actually total fakes with only a tiny cap inside a big can, so don't assume that all components, particularly the expensive ones, are genuine or OEM spec. At around 20 years of age, regardless of usage, I generally consider replacing or at least asking the owner rather than tinker with trying to reform cheap/suspect caps because that won't save dried-out caps that will become a serious problem regardless of how much re-forming is attempted. In any case, I still usually power up other people's gear and any seldom-used equipment with a lightbulb limiter (AKA dim-bulb tester or DBT) fitted. If properly and safely constructed, that's a simple, easily fitted device in the power line and experience with using one can tell you a lot about the condition of your power supply and amplifiers. There are plenty of U-tube videos for making them too.
Short version - re-forming is not a universal fix for dying caps.
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Electronic devices with electrolytic capacitors stored for long periods without use have which faults in the electrolytic capacitors?
Is turning on all electronic devices for 1 hour (60 minutes) enough or not to avoid these failures? Do you have any studies or information about them being assembled in electronic circuits?
Is turning on all electronic devices for 1 hour (60 minutes) enough or not to avoid these failures? Do you have any studies or information about them being assembled in electronic circuits?
When unused for a longer time, the capacitance of electrolytics goes down and the leakage current goes up.
Reforming concerns slowly turning up the voltage and use a series resistance to limit the leakage current. It's a chemical process.
When reforming you see the leakage current going down to the specified value. After the process the cap should have (close to) the original capacitance.
The danger from just turning on the equipment after a long time is that the leakage current is so high that it heats up the cap (V x I) and it fails due to overheating. So if your amp has been off for a long time, try to slowly turn it on with a variac. Like letting it sit at half mains for an hour.
Jan
Reforming concerns slowly turning up the voltage and use a series resistance to limit the leakage current. It's a chemical process.
When reforming you see the leakage current going down to the specified value. After the process the cap should have (close to) the original capacitance.
The danger from just turning on the equipment after a long time is that the leakage current is so high that it heats up the cap (V x I) and it fails due to overheating. So if your amp has been off for a long time, try to slowly turn it on with a variac. Like letting it sit at half mains for an hour.
Jan
I don't have a variac, there is no resistor and the electrolytic capacitors are soldered on the PCB of the electronic devices, in this case what is the study and manufacturers recommendation?
Lemme try again.
First question:
Long time storage increases leakage current, which often (but not always) can be cured by periodic re-forming (or use) with little used caps.
I measured many unused caps having been stored for 20 years or more. None of them showed signs of dry-out like decreased capacitance or increased ESR.
Second question:
There's no general answer.
Turning on the equipment for at least 1 hour every year or so can help to increase ecap life by decreasing leakage current.
The longer the cap or equipment was stored the longer it should be powered.
But, if leakage current is already excessive, powering the equipment might cause the cap to explode or cause other equipment damage.
So it's a good idea to use a bulb limiter when cap condition is dubious.
There's no cap manufacturer recommendation available for caps built into equipment.
Reason is that cap manufacturers can't know how their caps are operated in the equipment.
Useable cap life depends on temperature, voltage and ripple current and of course on cap type.
E.g. the same cap can last 5000 hours or over 50000 hours depending on internal ambient temperature.
Generally cap lifetime doubles with 10°C lower can temperature.
If I turn on all the electronic devices for 1 hour to rebuild all the electrolytic capacitors, do you recommend turning them on every month? Any information from manufacturers on the topic of electrolytic capacitors mounted in circuits of electronic devices to connect these devices to reduce leakage current and loss of capacitance?
Is it true or myth, the more years electronic devices are stored, the more hours they must remain on?
Is it true or myth, the more years electronic devices are stored, the more hours they must remain on?
Here we go again....same questions, already answered! Read Rikaro's post #38 again. You may not have access to a variac but you could build a DBT to limit the damaging inrush current when powering up. If you can't build that, you won't be able to fix any real problem and you are wasting your time looking for recommended power-up intervals that somehow prevent capacitors from ageing. In any case, you still have to replace them sometime or your precious gear and sound quality will have deteriorated before you got to enjoy it.
Regarding manufacturer's advice on keeping their products alive..... Are you kidding? Capacitor manufacturers want you to replace their products or the device containing them regularly, not keep them alive indefinitely. Anyway, there's nothing that improves the sound of an old amplifier like new, good quality power supply caps. That's one reason why repairers often do this and generally, it increases customer satisfaction.
As said, reforming is more applicable to high voltage caps (tube amplifiers etc.) Low voltage caps (as in most solid state gear) won't always benefit from a reforming process which should really be carried out with slowly rising voltage. Simply powering up a solid state product regularly, like every month or so rather than annually, is likely to be beneficial but not necessarily the best way to do this.
Regarding manufacturer's advice on keeping their products alive..... Are you kidding? Capacitor manufacturers want you to replace their products or the device containing them regularly, not keep them alive indefinitely. Anyway, there's nothing that improves the sound of an old amplifier like new, good quality power supply caps. That's one reason why repairers often do this and generally, it increases customer satisfaction.
As said, reforming is more applicable to high voltage caps (tube amplifiers etc.) Low voltage caps (as in most solid state gear) won't always benefit from a reforming process which should really be carried out with slowly rising voltage. Simply powering up a solid state product regularly, like every month or so rather than annually, is likely to be beneficial but not necessarily the best way to do this.