Re: [Elecraft] Electrolytic Capacitor failure
When you turn on your power supply and it shows 26 volts, are you going to turn on your radio? Thus paying attention to the meters will protect your radio. If when operating a contest for hours and you find the output drops off, wouldn't you glance at the meters? As to power distribution devices, every contact and connection in the path adds resistance. This makes the voltage at the radio vary with load. And that variation increases the IMD emitted by your transmitter. I've seen and evaluated several brands of power distribution strips. All are pure crap! Not suitable for the dynamic load presented by a SSB or CW radio during transmit. Observe the power supply voltage on your radio during receive. Then in transmit with 100 watts key down. If it drops 0.5 volts or more, you have a power distribution problem. It is much better to connect the radio power cable direct to the power supply and put the power distribution strip in a bucket of water and leave it there. 73 Bob, K4TAX On 4/17/2020 9:03 PM, K8TE wrote: Having meters will protect my radio? I doubt that assertion. Most radios today remain connected to their power supplies even when turned off, much like a computer. In the case of a K3, it is always connected to the power supply, even when off. So unless we don't connect the K3 to the power supply until checking the power supply's Voltage, a Voltmeter on the power supply wouldn't do much good. Additionally, when operating the K3 for hours on end, like in a contest, who watches the power supply Voltmeter? I certainly don't. I don't know who would. Instead, I use one of those power distribution devices that shuts down Voltage to the equipment should it rise too high. 73, Bill, K8TE -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Having meters will protect my radio? I doubt that assertion. Most radios today remain connected to their power supplies even when turned off, much like a computer. In the case of a K3, it is always connected to the power supply, even when off. So unless we don't connect the K3 to the power supply until checking the power supply's Voltage, a Voltmeter on the power supply wouldn't do much good. Additionally, when operating the K3 for hours on end, like in a contest, who watches the power supply Voltmeter? I certainly don't. I don't know who would. Instead, I use one of those power distribution devices that shuts down Voltage to the equipment should it rise too high. 73, Bill, K8TE -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Contributing to the Astron fan mail… My main shack PS is Astron RS-50M with two RS-35M in backup. I originally had just the two RS-35M supplies but just had to move on up. Never a problem with any of them although the RS-35M supplies are not actively being used at this time. 73, phil, K7PEH > On Apr 17, 2020, at 1:52 PM, Lyn Norstad wrote: > > Currently (no pun intended) I am using an Astron VS35M which gives me a > linear, fully variable (both voltage and max current) metered supply. It's a > workhorse and the size is perfect for my shack. > > I also have a decent switching 35 amp supply as a backup. > > 73 > Lyn, W0LEN > > > -Original Message- > From: elecraft-boun...@mailman.qth.net > [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Bob McGraw K4TAX > Sent: Friday, April 17, 2020 2:50 PM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] Electrolytic Capacitor failure > > All of my supplies have both voltage and current meters and they are in > a position I can see them when I turn them on. With supplies which do > not have meters, when one turns them on, you never know in advance and > get what they deliver. In my case, I observe the meters BEFORE turning > on a radio. On more than one occasion this has saved a radio due to a > power supply regulation failure. Dumping 24 to 32 volts into a $3000 > radios is not very pretty. Oh yes, the supplies do have OVP, Over > Voltage Protection, but I've seen this fail as well and I've repaired > several supplies where this did fail. And one doesn't know it has > failed until the voltage goes to maximum value. Its too late then to > find out the OVP circuit has failed. A meter would have prevented > radio and accessory equipment damage. > > 73 > > Bob, K4TAX > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to phys...@mac.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Currently (no pun intended) I am using an Astron VS35M which gives me a linear, fully variable (both voltage and max current) metered supply. It's a workhorse and the size is perfect for my shack. I also have a decent switching 35 amp supply as a backup. 73 Lyn, W0LEN -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Bob McGraw K4TAX Sent: Friday, April 17, 2020 2:50 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Electrolytic Capacitor failure All of my supplies have both voltage and current meters and they are in a position I can see them when I turn them on. With supplies which do not have meters, when one turns them on, you never know in advance and get what they deliver. In my case, I observe the meters BEFORE turning on a radio. On more than one occasion this has saved a radio due to a power supply regulation failure. Dumping 24 to 32 volts into a $3000 radios is not very pretty. Oh yes, the supplies do have OVP, Over Voltage Protection, but I've seen this fail as well and I've repaired several supplies where this did fail. And one doesn't know it has failed until the voltage goes to maximum value. Its too late then to find out the OVP circuit has failed. A meter would have prevented radio and accessory equipment damage. 73 Bob, K4TAX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
I guess I'm fortunate, I've had Astrons running 24/7 for decades without any failure. A 20A powers my repeater (IRLP node, 25 watt), a 35A power the Elecraft products and I just installed a 60A rack mount to replace them both (all are adjusted to 14.2 for spectral purity plus I can charge LiFePo4 too). Rick NK7I On 4/17/2020 12:49 PM, Bob McGraw K4TAX wrote: I have always been taught and thus have a concern when power supplies of excessive capacity are used for any type of service. If the wiring, in this case, between the power supply and the radio is #12 or #14 of any length typically supplied by radio companies, should a short occur in the power cable, it is likely the power supply will deliver full current. That will quickly melt the insulation on the power cable and could cause a fire before the power supply goes into current limit. Now at the same time, each power cable could be fused at the supply to limit the amount of current the supply can drive into the cable. I have to say I don't like this idea as the in-line fuse adds a significant amount of resistance and will impact the stability or degree of regulation of the voltage at the radio under a dynamic changing load such as SSB or CW. All of this is no different than when one uses a battery for their radio. In auto installations, for that reason, it is highly recommended that a fuse or circuit breaker be located at or very near the battery. Same applies here where the supply is capable of delivering very high amperage. I realize power supplies of this nature have over current protection. However, 70 amps through #14 wire will will produce lots of heat and smoke amazingly fast. The correct solution is not so simple in one sense of the word. The better solution is to use properly rated supplies for the required load. For that very reason, I have two 30 amp CCS rated supplies on my desk. One feeds the Elecraft 100 watt transceiver while the other feeds the Tentec Eagle 100 watt transceiver. All of my supplies have both voltage and current meters and they are in a position I can see them when I turn them on. With supplies which do not have meters, when one turns them on, you never know in advance and get what they deliver. In my case, I observe the meters BEFORE turning on a radio. On more than one occasion this has saved a radio due to a power supply regulation failure. Dumping 24 to 32 volts into a $3000 radios is not very pretty. Oh yes, the supplies do have OVP, Over Voltage Protection, but I've seen this fail as well and I've repaired several supplies where this did fail. And one doesn't know it has failed until the voltage goes to maximum value. Its too late then to find out the OVP circuit has failed. A meter would have prevented radio and accessory equipment damage. 73 Bob, K4TAX On 4/17/2020 12:28 PM, j...@kk9a.com wrote: I also use an Astron RS-70 for my K3Ss. Like you, mine was not purchased for this purpose. It is under my desk so the physical size is not an issue and I have no worries about overloading it. John KK9A Barry w2up at comcast.net I got a kick out of "big hulking supply," too. I have an RS-70 on my K3. It used to power a lot more stuff, but since I downsized my station, it loafs along. Definitely overkill, but it sits under the desk, out of the way, so why not? Oh yeah, my keyer's on it, too, and still doesn't get warm, even at QRQ :-) Barry W2UP __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rick.n...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
I have always been taught and thus have a concern when power supplies of excessive capacity are used for any type of service. If the wiring, in this case, between the power supply and the radio is #12 or #14 of any length typically supplied by radio companies, should a short occur in the power cable, it is likely the power supply will deliver full current. That will quickly melt the insulation on the power cable and could cause a fire before the power supply goes into current limit. Now at the same time, each power cable could be fused at the supply to limit the amount of current the supply can drive into the cable. I have to say I don't like this idea as the in-line fuse adds a significant amount of resistance and will impact the stability or degree of regulation of the voltage at the radio under a dynamic changing load such as SSB or CW. All of this is no different than when one uses a battery for their radio. In auto installations, for that reason, it is highly recommended that a fuse or circuit breaker be located at or very near the battery. Same applies here where the supply is capable of delivering very high amperage. I realize power supplies of this nature have over current protection. However, 70 amps through #14 wire will will produce lots of heat and smoke amazingly fast. The correct solution is not so simple in one sense of the word. The better solution is to use properly rated supplies for the required load. For that very reason, I have two 30 amp CCS rated supplies on my desk. One feeds the Elecraft 100 watt transceiver while the other feeds the Tentec Eagle 100 watt transceiver. All of my supplies have both voltage and current meters and they are in a position I can see them when I turn them on. With supplies which do not have meters, when one turns them on, you never know in advance and get what they deliver. In my case, I observe the meters BEFORE turning on a radio. On more than one occasion this has saved a radio due to a power supply regulation failure. Dumping 24 to 32 volts into a $3000 radios is not very pretty. Oh yes, the supplies do have OVP, Over Voltage Protection, but I've seen this fail as well and I've repaired several supplies where this did fail. And one doesn't know it has failed until the voltage goes to maximum value. Its too late then to find out the OVP circuit has failed. A meter would have prevented radio and accessory equipment damage. 73 Bob, K4TAX On 4/17/2020 12:28 PM, j...@kk9a.com wrote: I also use an Astron RS-70 for my K3Ss. Like you, mine was not purchased for this purpose. It is under my desk so the physical size is not an issue and I have no worries about overloading it. John KK9A Barry w2up at comcast.net I got a kick out of "big hulking supply," too. I have an RS-70 on my K3. It used to power a lot more stuff, but since I downsized my station, it loafs along. Definitely overkill, but it sits under the desk, out of the way, so why not? Oh yeah, my keyer's on it, too, and still doesn't get warm, even at QRQ :-) Barry W2UP __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
I also use an Astron RS-70 for my K3Ss. Like you, mine was not purchased for this purpose. It is under my desk so the physical size is not an issue and I have no worries about overloading it. John KK9A Barry w2up at comcast.net I got a kick out of "big hulking supply," too. I have an RS-70 on my K3. It used to power a lot more stuff, but since I downsized my station, it loafs along. Definitely overkill, but it sits under the desk, out of the way, so why not? Oh yeah, my keyer's on it, too, and still doesn't get warm, even at QRQ :-) Barry W2UP __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
I got a kick out of "big hulking supply," too. I have an RS-70 on my K3. It used to power a lot more stuff, but since I downsized my station, it loafs along. Definitely overkill, but it sits under the desk, out of the way, so why not? Oh yeah, my keyer's on it, too, and still doesn't get warm, even at QRQ :-) Barry W2UP donovanf wrote > This is probably unrelated to your capacitor failure, but your > "big hulking linear supply" is underrated for the K3 unless you > run your K3 at less than full output power. The RS-20A might > be okay for SSB, but certainly not for RTTY or digital modes at > K3 full rated output power. > > > > 73 > Frank > W3LPL -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Hi David, I was a civilian Electrical Engineer with the US Army before the FAA stint. We absolutely required the components used in critical systems to be operated well below the "rated" thresholds. I did HV substation design for places such as Marshall Space Flight Center and Redstone Arsenal - the Army missle development center where the original Redstone rocket was developed to launch the USA's 1st satellite in 1958. I was bombarded by manufacturers wanting us to use the 'latest' electronic versions of the substation protective relaying systems in the 1990's which until then had been totally analog. I refused to allow that then, primarily because they relied on electrolytic capacitors in their 'power supply' & 'transient bypass' systems (internally to the relay). The electrolytic caps were the weak link. A 161Kv substation is no place for components sensitive to transients & guaranteed to fail after 10 yrs or so. Those same caps have destroyed more PC motherboards, HD TV sets, etc. than any other cause. I have a ESR meter which allows one to check PC board caps in circuit - It uses an AC low level voltage which will not cause semiconductors to activate, & which gives ESR values for the caps. We used to try to repair expensive PC boards in the FAA systems rather that "board changing". That way we could keep one good spare & fix the failed one when replaced, keeping it as the spare. Electrolytic Cap's were the main culprits in the failures. Thanks for the reply! 73 Gill __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Ray, I reported to this forum (ca. February 2019) a similar, though not identical, problem involving my K3/10 while running from an Astron RS-20A supply. My problem occurred in receive mode rather than transmit mode, which made it a bit more difficult to understand because the current demand for my K3 in receive mode is less than 1 A. After finding no problem using an alternate supply (Astron SS-30 or 12 V battery), I ripped my RS-20A apart to test the various parts on either side of the regulator board. To keep a long story short, the problem turned out to be the large electrolytic filter capacitor at the output of the rectifier block (ahead of the regulator board). It had no external signs of leakage or bulging, but its ESR (equivalent series resistance) had risen to perhaps 2-3 ohms. Finding it hard to believe this ESR could present the DC voltage and current oscillations I observed, I did a SPICE simulation of the transformer/rectifier/filter capacitor circuit with a load designed to draw about 1 A. A good capacitor (ESR = 0.05 ohms) showed hardly any DC voltage ripple, whereas the capacitor with 3 ohms ESR showed huge ripple. I didn't get a chance to put a scope on the actual RS-20A regulator input to confirm the simulation result, but it appears that the regulator circuit developed a low-frequency limit cycle oscillation when loaded by the K3/10 at 1 A current, likely due to the high amplitude voltage ripple at the regulator input caused by the elevated ESR of the filter capacitor. The DC bus voltage reported by the K3 toggled between two values, 13.6 V and 12.7 V. Motto of this story: even if an electrolytic doesn't appear bad externally, suspect increased ESR and replace it. 73, Mike, K8CN -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
They are rarely operated 24/7, and they aren't usually supervised by career engineers. Most hams are relatively inexperienced hobbyists who may not recognize a problem until it is catastrophic. Someone in this thread already mentioned that nearly all ham shacks have a bad electrolytic lurking under the bench. Eric KE6US On 4/16/2020 7:38 AM, CUTTER DAVID via Elecraft wrote: Hello Gill Doing reliability calculations to MIL 217 was very instructive many years ago and it taught me that operating well under the limits extended MTBF a lot. Some military customers instructed that specs were 60% or more degraded to achieve longer service life. What was your experience of that? It amazes me that amateur psus last so long! Then, again, they are rarely continuously operated 24/7. 73 David G3UNA/G6CP On 16 April 2020 at 15:19 Gill via Elecraft wrote: As Harlan pointed out - I was an engineer for the FAA until retirement - We changed electrolytics as part of normal PM's on critical systems usually every 5 years or so. CDE (Cornell Dubilier) indicates expected life (MTBF) of devices operated within rated voltage & temp specs to be about 80-100 thousand hours. Most failures occur quickly around the end of that period. For 24/7 operated systems, that translates to around 8-10 years before rapid EOL failures begin to occur. Electrolytics can be thought of like incandescent lamps - they have a finite useful life and the fail quickly around the end of that time. ESR (Equivalent Series (AC) resistance) increases which reflects in higher ripple currents in power supplies are a main culprit. Check out: https://www.cde.com/resources/technical-papers/reliability.pdf 73 Gill W4RYW __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to d.cut...@ntlworld.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to eric_c...@hotmail.com . __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
If Ray has a K3/10, then the power supply is perfectly fine. The recommendation for that is "13.8VDC @ 6A for K3/10”. There are a lot of K3/10’s in the field. Nothing in his post indicated which transceiver he has. However, if indeed he has a K3/100, then Frank is right (as usual). Ray should probably be using a heftier supply. Margins are important. 73! Jack, W6FB ps Thanks, Frank! > On Apr 15, 2020, at 10:22 PM, donov...@starpower.net wrote: > > Hi Ray, > > > This is probably unrelated to your capacitor failure, but your > "big hulking linear supply" is underrated for the K3 unless you > run your K3 at less than full output power. The RS-20A might > be okay for SSB, but certainly not for RTTY or digital modes at > K3 full rated output power. > > The Astron RS-20A specification: "amperage (continuous) 16 A, intermittent > 20A" > > > www.astrondistributors.com/astron-rs-20a-1667.html > > > The K3 manual recommends " 13.8VDC @ 25A continuous duty" > and specifies: "13.8 V nominal (11 V min, 15 V max). 17-22 A typical" > > > ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Owner's%20man%20A1.pdf > > > 73 > Frank > W3LPL > > > > - Original Message - > > From: "Ray Albers" > To: elecraft@mailman.qth.net > Sent: Wednesday, April 15, 2020 7:31:23 PM > Subject: [Elecraft] Electrolytic Capacitor failure > > I could use some knowledge and/or opinions on this subject (Radio/Elecraft > related only because it deals with a power supply that powers a K3!) > > The other day I was about to initiate a call, and as soon as I touched the > "dah" paddle the K3 instantly shut off. The cause was that the power > supply voltage dropped too low when the radio demanded more current. > > The power supply is an Astron RS-20A, a big hulking linear supply that I > really like. Huge heavy transformer and two series-pass transistors mounted > on big heat sinks - thus, quiet acoustically (no cooling fan) and > electrically (no RF hash from switching). I have two of these - one that I > bought for my new radio when I got back into ham radio after a long > absence and the other because I was at a hamfest where someone had a pile > of them that he was selling for only $20 each - who could resist? So I > trotted out the spare supply and got back on the air. Now to troubleshoot > the bad supply. > > I had trouble with this one about five years ago. The output transistors > are plugged into sockets, and on one socket the contacts for the emitter > pin had gotten loose, and there was a vicious spiral of heat causing more > resistance causing more heat until eventually it actually melted the > transistor pin and left a black char on the socket. When I replaced the > socket that time, I decided to solder the emitter pins on both transistors. > > It took me a long time to find the problem this time. Various tests told me > the transformer, the full-wave rectifier diodes and the pass transistors > were fine. Finally - with some help from hints in a great article about > Astron supplies on repeaterbuilder dot com - I figured out that the supply > voltage to the regulator board was too low, so there was not enough "oomph" > available to drive the output transistors when high current was demanded. > > This supply voltage comes from a center tapped transformer secondary > feeding two small diodes (both of which checked OK) to a 1000uF 35 V > electrolytic. Turns out the capacitor was bad. It's a typical aluminum case > with blue plastic covering (which I assume to be heat-shrink plastic > because of the way it is completely molded around the capacitor.) > Replacing it brought the supply voltage up to spec, and now everything > works fine. > > But I was surprised about the capacitor failure. Absolutely no visible > signs of anything wrong - no bulging, leaking, etc. And the soldering to > the PC board is perfect. So here's my question for the group: What do we > know about electrolytic capacitor failures? I know that anyone restoring > an old ham transmitter or receiver or BC receiver almost always has to > re-cap it, because the ancient electrolytics, which are usually wet > electrolytics in chassis-mounted cans, will have gone bad. But this is the > first time I've ever had a failure of the more modern type electrolytics. A > quick search of capacitor failure on Google shocked me when I read claims > in several places that these capacitors are only expected to have a two to > five year life!! Can that be? I know I've got lots of radio gear that's > way older than that and still working fine. To do this repair, I replaced a > capacitor that might only be 5 years old with one that is probably twenty > years old! > > Words of wisdom and enlightenment would be most welcome! > > 73 > Ray K2HYD > (K3 #8240, KX-3 #6827) > __ > Elecraft mailing list > Home:
Re: [Elecraft] Electrolytic Capacitor failure
I also retired from FAA. Maybe the Air Defense Long Range ARSR 4 RADARs , BI-6, MODE-S and dozens of other 24/7 sytems, are not "critical systems". Power supply issues were rare. Some of the most robust supplies I have ever experienced. Every ham shack I have ever seen has at least one bad one under the bench. What destroyed the FAA is fanatical political correctness. 73 Leroy AB7CE -Original Message- From: Gill via Elecraft Sent: Thursday, April 16, 2020 8:19 AM To: elecraft@mailman.qth.net Subject: [Elecraft] Electrolytic Capacitor failure As Harlan pointed out - I was an engineer for the FAA until retirement - We changed electrolytics as part of normal PM's on critical systems usually every 5 years or so. CDE (Cornell Dubilier) indicates expected life (MTBF) of devices operated within rated voltage & temp specs to be about 80-100 thousand hours. Most failures occur quickly around the end of that period. For 24/7 operated systems, that translates to around 8-10 years before rapid EOL failures begin to occur. Electrolytics can be thought of like incandescent lamps - they have a finite useful life and the fail quickly around the end of that time. ESR (Equivalent Series (AC) resistance) increases which reflects in higher ripple currents in power supplies are a main culprit. Check out: https://www.cde.com/resources/technical-papers/reliability.pdf 73 Gill W4RYW __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Hello Gill Doing reliability calculations to MIL 217 was very instructive many years ago and it taught me that operating well under the limits extended MTBF a lot. Some military customers instructed that specs were 60% or more degraded to achieve longer service life. What was your experience of that? It amazes me that amateur psus last so long! Then, again, they are rarely continuously operated 24/7. 73 David G3UNA/G6CP > On 16 April 2020 at 15:19 Gill via Elecraft wrote: > > > As Harlan pointed out - I was an engineer for the FAA until retirement - > We changed electrolytics as part of normal PM's on critical systems > usually every 5 years or so. CDE (Cornell Dubilier) indicates expected > life (MTBF) of devices operated within rated voltage & temp specs to be > about 80-100 thousand hours. Most failures occur quickly around the end > of that period. For 24/7 operated systems, that translates to around > 8-10 years before rapid EOL failures begin to occur. Electrolytics can > be thought of like incandescent lamps - they have a finite useful life > and the fail quickly around the end of that time. ESR (Equivalent Series > (AC) resistance) increases which reflects in higher ripple currents in > power supplies are a main culprit. Check out: > https://www.cde.com/resources/technical-papers/reliability.pdf > 73 Gill W4RYW > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to d.cut...@ntlworld.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Hi Ray, This is probably unrelated to your capacitor failure, but your "big hulking linear supply" is underrated for the K3 unless you run your K3 at less than full output power. The RS-20A might be okay for SSB, but certainly not for RTTY or digital modes at K3 full rated output power. The Astron RS-20A specification: "amperage (continuous) 16 A, intermittent 20A" www.astrondistributors.com/astron-rs-20a-1667.html The K3 manual recommends " 13.8VDC @ 25A continuous duty" and specifies: "13.8 V nominal (11 V min, 15 V max). 17-22 A typical" ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Owner's%20man%20A1.pdf 73 Frank W3LPL - Original Message - From: "Ray Albers" To: elecraft@mailman.qth.net Sent: Wednesday, April 15, 2020 7:31:23 PM Subject: [Elecraft] Electrolytic Capacitor failure I could use some knowledge and/or opinions on this subject (Radio/Elecraft related only because it deals with a power supply that powers a K3!) The other day I was about to initiate a call, and as soon as I touched the "dah" paddle the K3 instantly shut off. The cause was that the power supply voltage dropped too low when the radio demanded more current. The power supply is an Astron RS-20A, a big hulking linear supply that I really like. Huge heavy transformer and two series-pass transistors mounted on big heat sinks - thus, quiet acoustically (no cooling fan) and electrically (no RF hash from switching). I have two of these - one that I bought for my new radio when I got back into ham radio after a long absence and the other because I was at a hamfest where someone had a pile of them that he was selling for only $20 each - who could resist? So I trotted out the spare supply and got back on the air. Now to troubleshoot the bad supply. I had trouble with this one about five years ago. The output transistors are plugged into sockets, and on one socket the contacts for the emitter pin had gotten loose, and there was a vicious spiral of heat causing more resistance causing more heat until eventually it actually melted the transistor pin and left a black char on the socket. When I replaced the socket that time, I decided to solder the emitter pins on both transistors. It took me a long time to find the problem this time. Various tests told me the transformer, the full-wave rectifier diodes and the pass transistors were fine. Finally - with some help from hints in a great article about Astron supplies on repeaterbuilder dot com - I figured out that the supply voltage to the regulator board was too low, so there was not enough "oomph" available to drive the output transistors when high current was demanded. This supply voltage comes from a center tapped transformer secondary feeding two small diodes (both of which checked OK) to a 1000uF 35 V electrolytic. Turns out the capacitor was bad. It's a typical aluminum case with blue plastic covering (which I assume to be heat-shrink plastic because of the way it is completely molded around the capacitor.) Replacing it brought the supply voltage up to spec, and now everything works fine. But I was surprised about the capacitor failure. Absolutely no visible signs of anything wrong - no bulging, leaking, etc. And the soldering to the PC board is perfect. So here's my question for the group: What do we know about electrolytic capacitor failures? I know that anyone restoring an old ham transmitter or receiver or BC receiver almost always has to re-cap it, because the ancient electrolytics, which are usually wet electrolytics in chassis-mounted cans, will have gone bad. But this is the first time I've ever had a failure of the more modern type electrolytics. A quick search of capacitor failure on Google shocked me when I read claims in several places that these capacitors are only expected to have a two to five year life!! Can that be? I know I've got lots of radio gear that's way older than that and still working fine. To do this repair, I replaced a capacitor that might only be 5 years old with one that is probably twenty years old! Words of wisdom and enlightenment would be most welcome! 73 Ray K2HYD (K3 #8240, KX-3 #6827) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
Very short unless that was a design goal! It’s all about temperature. Operate an 85c electrolytic near 85c and it’s not going to be around long. 73 Josh W6XU Sent from my mobile device > On Apr 15, 2020, at 1:09 PM, John Kosko wrote: > > Two to five year life span sounds a little short to me. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Electrolytic Capacitor failure
I retired in 2016 after 34 years as the metrology supervisor at a commercial nuclear power plant. I couldn’t count the number of equipment failures due to electrolytic capacitors, WAY TOO MANY. Some brands of equipment had high percentage failures while other brands had low. Seems the manufacture of the CAPACITOR was a better indicator of failure rate. Many equipment manufacturers used capacitors that carried brands from Japan, others used Sprague (which is probably made in Japan as well, but seemed to hold up much better). Leakage current and capacitance value change seemed to be the culprits most of the time. For our “standards” we added a step to our calibration procedures to check all power supply ripple voltages to insure they were in spec. For all other test equipment, we would do the ripple checks any time the equipment was in the lab for repair. Also, the plant itself had preventative maintenance procedures to energize certain (safety critical) electrolytic capacitors in our warehouse once a year. Sent from my iPhone > On Apr 15, 2020, at 3:33 PM, Ray Albers wrote: > > I could use some knowledge and/or opinions on this subject (Radio/Elecraft > related only because it deals with a power supply that powers a K3!) > > The other day I was about to initiate a call, and as soon as I touched the > "dah" paddle the K3 instantly shut off. The cause was that the power > supply voltage dropped too low when the radio demanded more current. > > The power supply is an Astron RS-20A, a big hulking linear supply that I > really like. Huge heavy transformer and two series-pass transistors mounted > on big heat sinks - thus, quiet acoustically (no cooling fan) and > electrically (no RF hash from switching). I have two of these - one that I > bought for my new radio when I got back into ham radio after a long > absence and the other because I was at a hamfest where someone had a pile > of them that he was selling for only $20 each - who could resist? So I > trotted out the spare supply and got back on the air. Now to troubleshoot > the bad supply. > > I had trouble with this one about five years ago. The output transistors > are plugged into sockets, and on one socket the contacts for the emitter > pin had gotten loose, and there was a vicious spiral of heat causing more > resistance causing more heat until eventually it actually melted the > transistor pin and left a black char on the socket. When I replaced the > socket that time, I decided to solder the emitter pins on both transistors. > > It took me a long time to find the problem this time. Various tests told me > the transformer, the full-wave rectifier diodes and the pass transistors > were fine. Finally - with some help from hints in a great article about > Astron supplies on repeaterbuilder dot com - I figured out that the supply > voltage to the regulator board was too low, so there was not enough "oomph" > available to drive the output transistors when high current was demanded. > > This supply voltage comes from a center tapped transformer secondary > feeding two small diodes (both of which checked OK) to a 1000uF 35 V > electrolytic. Turns out the capacitor was bad. It's a typical aluminum case > with blue plastic covering (which I assume to be heat-shrink plastic > because of the way it is completely molded around the capacitor.) > Replacing it brought the supply voltage up to spec, and now everything > works fine. > > But I was surprised about the capacitor failure. Absolutely no visible > signs of anything wrong - no bulging, leaking, etc. And the soldering to > the PC board is perfect. So here's my question for the group: What do we > know about electrolytic capacitor failures? I know that anyone restoring > an old ham transmitter or receiver or BC receiver almost always has to > re-cap it, because the ancient electrolytics, which are usually wet > electrolytics in chassis-mounted cans, will have gone bad. But this is the > first time I've ever had a failure of the more modern type electrolytics. A > quick search of capacitor failure on Google shocked me when I read claims > in several places that these capacitors are only expected to have a two to > five year life!! Can that be? I know I've got lots of radio gear that's > way older than that and still working fine. To do this repair, I replaced a > capacitor that might only be 5 years old with one that is probably twenty > years old! > > Words of wisdom and enlightenment would be most welcome! > > 73 > Ray K2HYD > (K3 #8240, KX-3 #6827) > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to hsherr...@reagan.com
Re: [Elecraft] Electrolytic Capacitor failure
I don't know that I would run a K3 off a 20A power supply. You're stressing both. Did you mean to say 30A? Buck, k4ia Honor Roll 8BDXCC EasyWayHamBooks.com On 4/15/2020 3:31 PM, Ray Albers wrote: I could use some knowledge and/or opinions on this subject (Radio/Elecraft related only because it deals with a power supply that powers a K3!) The other day I was about to initiate a call, and as soon as I touched the "dah" paddle the K3 instantly shut off. The cause was that the power supply voltage dropped too low when the radio demanded more current. The power supply is an Astron RS-20A, a big hulking linear supply that I really like. Huge heavy transformer and two series-pass transistors mounted on big heat sinks - thus, quiet acoustically (no cooling fan) and electrically (no RF hash from switching). I have two of these - one that I bought for my new radio when I got back into ham radio after a long absence and the other because I was at a hamfest where someone had a pile of them that he was selling for only $20 each - who could resist? So I trotted out the spare supply and got back on the air. Now to troubleshoot the bad supply. I had trouble with this one about five years ago. The output transistors are plugged into sockets, and on one socket the contacts for the emitter pin had gotten loose, and there was a vicious spiral of heat causing more resistance causing more heat until eventually it actually melted the transistor pin and left a black char on the socket. When I replaced the socket that time, I decided to solder the emitter pins on both transistors. It took me a long time to find the problem this time. Various tests told me the transformer, the full-wave rectifier diodes and the pass transistors were fine. Finally - with some help from hints in a great article about Astron supplies on repeaterbuilder dot com - I figured out that the supply voltage to the regulator board was too low, so there was not enough "oomph" available to drive the output transistors when high current was demanded. This supply voltage comes from a center tapped transformer secondary feeding two small diodes (both of which checked OK) to a 1000uF 35 V electrolytic. Turns out the capacitor was bad. It's a typical aluminum case with blue plastic covering (which I assume to be heat-shrink plastic because of the way it is completely molded around the capacitor.) Replacing it brought the supply voltage up to spec, and now everything works fine. But I was surprised about the capacitor failure. Absolutely no visible signs of anything wrong - no bulging, leaking, etc. And the soldering to the PC board is perfect. So here's my question for the group: What do we know about electrolytic capacitor failures? I know that anyone restoring an old ham transmitter or receiver or BC receiver almost always has to re-cap it, because the ancient electrolytics, which are usually wet electrolytics in chassis-mounted cans, will have gone bad. But this is the first time I've ever had a failure of the more modern type electrolytics. A quick search of capacitor failure on Google shocked me when I read claims in several places that these capacitors are only expected to have a two to five year life!! Can that be? I know I've got lots of radio gear that's way older than that and still working fine. To do this repair, I replaced a capacitor that might only be 5 years old with one that is probably twenty years old! Words of wisdom and enlightenment would be most welcome! 73 Ray K2HYD (K3 #8240, KX-3 #6827) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to radiok...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
