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Electrolytic Capacitor failure

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Ray Albers-2

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)
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Buck

Re: 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:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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Elecraft mailing list

Re: Electrolytic Capacitor failure

In reply to this post by Ray Albers-2

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 <[hidden email]> 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:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

John Kosko

Electrolytic Capacitor failure

In reply to this post by Ray Albers-2

Two to five year life span sounds a little short to me. I’ve been earning my primary income in electronics for over 60 years and my experience shows that most electrolytic capacitors last between ten and twenty years. But, usually they will show leakage around seals before they fail. I guess it was just your turn to have an odd situation. Expert help on electrolytic capacitors is available on YouTube. Search on “mr carlsons lab” (without the quote marks). He restores a lot of antique equipment and videos the whole thing. No, I don’t have any monetary connection with Mr. Carlson or his lab. He’s a worthy Elmer in regard to maintaining older equipment.

Regards,
John Kosko K8TCT
(K3S 11718 powered by a 35 year old Sorenson HPD 15-20 switcher set for 13.6VDC with the DC power cable running through 5 turns around a toroid core)

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

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Josh Fiden

Re: 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 <[hidden email]> wrote:
>
> Two to five year life span sounds a little short to me.

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donovanf

Re: Electrolytic Capacitor failure

In reply to this post by Ray Albers-2

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" <[hidden email]>
To: [hidden email]
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)
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Post: mailto:[hidden email]

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Re: 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, [hidden email] 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" <[hidden email]>
> To: [hidden email]
> 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:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
> ______________________________________________________________
> Elecraft mailing list
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Mike K8CN

Re: Electrolytic Capacitor failure

In reply to this post by Ray Albers-2

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/
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Barry

Re: Electrolytic Capacitor failure

In reply to this post by donovanf

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/
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john@kk9a.com

Re: Electrolytic Capacitor failure

In reply to this post by Ray Albers-2

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

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Bob McGraw - K4TAX

Re: 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, [hidden email] 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:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Rick Bates, NK7I

Re: 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, [hidden email] 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:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Lyn WØLEN

Re: Electrolytic Capacitor failure

In reply to this post by Bob McGraw - K4TAX

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: [hidden email] [mailto:[hidden email]] On Behalf Of Bob McGraw K4TAX
Sent: Friday, April 17, 2020 2:50 PM
To: [hidden email]
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

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Elecraft mailing list
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Elecraft mailing list

Re: 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 <[hidden email]> 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: [hidden email] [mailto:[hidden email]] On Behalf Of Bob McGraw K4TAX
> Sent: Friday, April 17, 2020 2:50 PM
> To: [hidden email]
> 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:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

K8TE

Re: Electrolytic Capacitor failure

In reply to this post by Bob McGraw - K4TAX

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

--
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Bob McGraw - K4TAX

Re: 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/
> ______________________________________________________________
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> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
> This list hosted by: http://www.qsl.net
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> Message delivered to [hidden email]
>

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