8 May
2012
8 May
'12
6:19 p.m.
Hi Gene :)
On Tue, 2012-05-08 at 11:13 -0400, gene heskett wrote:
I guess I already found the problem. On the primary side there are a 1u
50V and a 47u 25V capacitor, both 85°C. Thomas said I should replace
them with > 100°C, even if they look ok.
I've got capacitors on stock, but bad equipment for soldering. Unsolder
already was hard, but I can't get it soldered, especially since the 47u
I've got, has got a larger diameter, since it's a 35V. Reading glasses
btw. are less good for soldering, I need to find a better tool to see
when soldering. Thomas has got some special glasses.
On Tuesday, May 08, 2012 10:32:50 AM Ralf Mardorf did
opine:
When I turned
on my 7 year old Behringer
Using its age as a clue, I think I would be gong through it with a
"Capacitor Wizard" checking the caps in the psu in particular. I haven't a clue what it may be called on your
side of the pond though, so
I will describe what it does in hopes it might be recognizable as a euro
made and named testing device.
It is a small, low power oscillator, generating about 85 millivolts of rf
signal, at a nominal frequency of 100 kilohertz, the currant it can send
through a capacitor is presented on a meter, usually calibrated with a knob
so that it reads full scale when the probes are shorted together.
Thomas has got Hameg oscilloscopes with component testers.
Btw. the capacitors I unsoldered are broken now, even if they should
have been ok before. Not because of heat, but to take hold of the
capacitors damaged them.
Having a spare for that sort of thing is a good idea.
Asking if it will
fail is like asking if freshly poured concrete will crack. The "if" is
wrong, the correct word is "when", because it will, always. :)
I'm not a fan of switching power supplies.
Good luck Ralf.
Cheers, Gene
Thank you Gene, Thomas tries to visit me in some hours.
Ralf
8 May
8 May
6:47 p.m.
New subject: OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Tuesday, May 08, 2012 12:36:57 PM Ralf Mardorf did opine:
Hi Gene :)
On Tue, 2012-05-08 at 11:13 -0400, gene heskett wrote:
This thing, because of the very low level of signal used, does not 'turn
on' any semiconductor junctions, so they disappear from its view. That
means you can do a very reliable test while it is in circuit, before you
warm up the iron.
When I took a chance and spent $175 of the tv stations money for it, close
to 20 years ago now, I was initially a little dubious, but that thing has
turned out to be worth at least as much as sliced bread or bottled beer,
and has probably saved me many hundreds of hours of troubleshooting time
since. That, a good temp controlled iron, and a good scope (and the brains
to see what its telling you) are the 4 most indispensable tools a techie
can have. I left out the dvm because everyone has one of those today...
On Tuesday, May 08, 2012 10:32:50 AM Ralf Mardorf
did opine:
I guess I already found the problem. On the primary side there are a 1u
50V and a 47u 25V capacitor, both 85آ°C. Thomas said I should replace
them with > 100آ°C, even if they look ok.
I've got capacitors on stock, but bad equipment for soldering. Unsolder
already was hard, but I can't get it soldered, especially since the 47u
I've got, has got a larger diameter, since it's a 35V. Reading glasses
btw. are less good for soldering, I need to find a better tool to see
when soldering. Thomas has got some special glasses.
When I turned on my 7 year old Behringer
Using its age as a clue, I think I would be gong through it with a
"Capacitor Wizard" checking the caps in the psu in particular. I haven't a clue what it may be called on
your side of the pond
though, so I will describe what it does in hopes it might be
recognizable as a euro made and named testing device.
It is a small, low power oscillator, generating about 85 millivolts of
rf signal, at a nominal frequency of 100 kilohertz, the currant it
can send through a capacitor is presented on a meter, usually
calibrated with a knob so that it reads full scale when the probes
are shorted together.
Thomas has got Hameg oscilloscopes with component testers.
Btw. the capacitors I unsoldered are broken now, even
if they should
have been ok before. Not because of heat, but to take hold of the
capacitors damaged them.
You are welcome. I hope I helped.
Cheers, Gene
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: <http://coyoteden.dyndns-free.com:85/gene>
A banker is a fellow who lends you his umbrella when the sun is shining
and wants it back the minute it begins to rain.
-- Mark Twain
Having a spare for that sort of thing is a good
idea. Asking if it
will fail is like asking if freshly poured concrete will crack. The
"if" is wrong, the correct word is "when", because it will, always.
:)
I'm not a fan of switching power supplies.
Good luck Ralf.
Cheers, Gene
Thank you Gene, Thomas tries to visit me in some hours.
Ralf
9 May
9 May
10:23 a.m.
New subject: [solved] OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Tue, 2012-05-08 at 12:47 -0400, gene heskett wrote:
I hope I helped.
You confirmed that it's a good idea to replace the capacitors, regarding
to the age of the PSU. Yes, you helped.
Btw. the capacitors I unsoldered where still perfectly ok.
Not all capaictors are tested but we guess all are still ok, we anyway
will replace them.
We needed a good magnifier to see that a diode (IIRC near the
opto-coupler) had a could solder point. I couldn't see it with the
magnifier I own.
The main issue seems to be that one HER 300 (a 50 ns fast diode) for
rectification on the secondary side is borked.
After we found out this, we found out that the Behringer UB-SPSU2 is
known for this issue. Btw. it's also possible to get the circuit diagram
in the Internet for free.
The diode does cost nothing, but it's not easy to get here. No equation
diode. We found out that there's one diode IIRC >= 3A >= 200V <= 50ns
does exist here, Thomas anyway will order a HER 300. I didn't find it at
my dealer. So no mixer today, I need to test my Ubuntu Studio by
directly connecting to the Amp or using the headphone output of the RME
card.
A note. Thomas has got best equipment from Weller for unsoldering and
soldering, but even he had issues to unsolder and solder. He was near to
take it along to his employment to do it with hot air.
It's possible to do it with my Ersa C25 and a soldering tip that doesn't
cause tinder, but since it's even hard with best Weller equipment for
somebody who does such work everyday, it's no fun to repair the PSU.
Thanks,
Ralf
6:02 p.m.
New subject: [solved] OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Wednesday, May 09, 2012 11:40:31 AM Ralf Mardorf did opine:
On Tue, 2012-05-08 at 12:47 -0400, gene heskett
wrote:
Could=cold=microscopic crack in the solder?
I hope I helped.
You confirmed that it's a good idea to replace the capacitors, regarding
to the age of the PSU. Yes, you helped.
Btw. the capacitors I unsoldered where still perfectly ok.
Not all capaictors are tested but we guess all are still ok, we anyway
will replace them.
We needed a good magnifier to see that a diode (IIRC near the
opto-coupler) had a could solder point. I couldn't see it with the
magnifier I own. The main issue seems to be that one HER 300 (a 50 ns
fast diode) for
rectification on the secondary side is borked.
After we found out this, we found out that the Behringer UB-SPSU2 is
known for this issue. Btw. it's also possible to get the circuit diagram
in the Internet for free.
The diode does cost nothing, but it's not easy to get here. No equation
diode. We found out that there's one diode IIRC >= 3A >= 200V <= 50ns
does exist here, Thomas anyway will order a HER 300. I didn't find it at
my dealer. So no mixer today, I need to test my Ubuntu Studio by
directly connecting to the Amp or using the headphone output of the RME
card.
I'm not familiar with that particular diode. However power rated switching
diodes that fast really stretch the limits of the technology, so I would
expect a higher failure rate for that compared to the 3 to 20 microsecond
recovery times of a more normal power diode.
This recovery time can result in some interesting side effects, which has
nothing to do with your problem. Back in the 70's, I was a tx supervisor
for the Nebraska ETV Commissions KXNE, channel 19 site in northeastern
Nebraska. A GE transmitter, rated at 30kw out, it used a pair of Varian
4KM100LA klystrons for final amplifiers. Those things are hungry, needing
about 19.5 to 20 kilovolts at about 10 amps to run both of them. 20kv*10
amps is 200 kilowatts every hour its running. The supply was a triplet of
240 volt out, 14.4 kilovolt, 75kw rated line powerline distribution
transformers running backwards, which fed a 6 diode full wave bridge. Each
of those 'diodes' was actually about 60 std DO-5 diodes in series, with a
small capacitor and a small resistor across each one to equalize the
reverse voltages when they were off.
But those old diodes had about a 20 microsecond turnoff time, so there was
6 spikes of time during the ac cycle when the still turned on diodes caused
a very effective phase to phase short for that 20 microseconds. That was
relatively minor, but when they all finally turned off, the spike on the
powerline was a sight to behold. Coming out of every wall socket in the
building was the usual 124-127 volts ac, but superimposed were these
voltage spikes about 5 microseconds wide, and as much as 3 kilovolts peak.
Light bulbs and small equipment fuses didn't last as long as they should
have for obvious reasons.
A note. Thomas has got best equipment from Weller for
unsoldering and
soldering, but even he had issues to unsolder and solder. He was near to
take it along to his employment to do it with hot air.
It's possible to do it with my Ersa C25 and a soldering tip that doesn't
cause tinder, but since it's even hard with best Weller equipment for
somebody who does such work everyday, it's no fun to repair the PSU.
Thanks,
Ralf
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user(a)lists.linuxaudio.org
http://lists.linuxaudio.org/listinfo/linux-audio-user
Cheers, Gene
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: <http://coyoteden.dyndns-free.com:85/gene>
The human race is a race of cowards; and I am not only marching in that
procession but carrying a banner.
-- Mark Twain
6:22 p.m.
New subject: [solved] OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Wed, 2012-05-09 at 12:02 -0400, gene heskett wrote:
Could=cold=microscopic crack in the solder?
No a perfect looking joint had no contact to a pin, it only had conatct
to the board.
I'm not familiar with that particular diode.
However power rated switching
diodes that fast really stretch the limits of the technology, so I would
expect a higher failure rate for that compared to the 3 to 20 microsecond
recovery times of a more normal power diode.
Indeed. the HER 303 with 50ns is the second fast diode we found. Thomas
searched a lot and found another diode with 25ns or similar fast. He
never has seen such a fast diode in another switching supply.
I don't have any experiences. Yesterday I learned it and why just one
diode is needed.
3 kilovolts peak
That's why I would like to live in a house with several stages of
overvoltage protection. Those spark gap thingys from the DYI market or
the same crap 100 * more expensive from the musical instrument dealer
won't help if this happens. Even if the peak would be slow.
Light bulbs and small equipment fuses didn't last
as long as they should
have for obvious reasons.
:D
And it easily could go through the computer too.
Regards,
Ralf
11 May
11 May
6:11 a.m.
New subject: [solved] OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
10 May
10 May
2:38 a.m.
New subject: [solved] OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Wednesday, May 09, 2012 08:35:36 PM Ralf Mardorf did opine:
On Wed, 2012-05-09 at 12:02 -0400, gene heskett
wrote:
fortunately, the closest thing to a computer in those days was my TI SR-51.
Except for a few mainframes that cost millions, computers as we know them
now, were still a decade in the future, this was the '70's.
Could=cold=microscopic crack in the solder?
No a perfect looking joint had no contact to a pin, it only had conatct
to the board.
I'm not familiar with that particular diode.
However power rated
switching diodes that fast really stretch the limits of the
technology, so I would expect a higher failure rate for that compared
to the 3 to 20 microsecond recovery times of a more normal power
diode.
Indeed. the HER 303 with 50ns is the second fast diode we found. Thomas
searched a lot and found another diode with 25ns or similar fast. He
never has seen such a fast diode in another switching supply.
I don't have any experiences. Yesterday I learned it and why just one
diode is needed.
3 kilovolts peak
That's why I would like to live in a house with several stages of
overvoltage protection. Those spark gap thingys from the DYI market or
the same crap 100 * more expensive from the musical instrument dealer
won't help if this happens. Even if the peak would be slow.
Light bulbs and small equipment fuses didn't
last as long as they
should have for obvious reasons.
:
:D
And it easily could go through the computer too. Regards,
Ralf
Cheers, Gene
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: <http://coyoteden.dyndns-free.com:85/gene>
If you're happy, you're successful.
9 May
9 May
10:06 p.m.
New subject: OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Tuesday 08 May 2012 18:18:42 Ralf Mardorf wrote:
I'm not a fan of switching power supplies.
I thought the same when it comes to audio equipment. But one of my electronic
mentors teached me: "Isn't it better to have a PSU with internal frequencies
well in the MHz region to influence your audio (where its easy to filter) than
having a PSU with 50Hz and harmonics to influence your audio?"
Good luck with your soldering and check the PSU-output before you plug it into
your mixer.
Have fun,
Arnold
11:59 p.m.
New subject: OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
Thank you Arnold.
I agree that any technology comes with assets and drawbacks.
In the past we said that only discrete circuits with selected
semiconductors will produce good sound quality. Idiotic, since we
already used e.g. Curtis CEM and especially today we can buy some
elCheapo gear that comes very close to old high quality discrete
circuits, such as a mixing console for less than 300,-€.
I don't have tube equipment, but I like it. OTOH there's much elCheapo
tube equipment that does sound disgusting. We have a lot of fuss about
nothing.
Regards,
Ralf
10 May
10 May
10 a.m.
New subject: OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Wed, May 09, 2012 at 10:06:23PM +0200, Arnold Krille wrote:
I thought the same when it comes to audio equipment.
But one of my electronic
mentors teached me: "Isn't it better to have a PSU with internal frequencies
well in the MHz region to influence your audio (where its easy to filter) than
having a PSU with 50Hz and harmonics to influence your audio?"
Your mentor is missing the point that even for a switched mode PSU the
input is 50 or 60 Hz, and *something* has to store enough energy to bridge
the gaps between half cycle peaks. So you'll get mains harmonics anyway,
just as with a linear PSU.
Ciao,
--
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
2:25 p.m.
New subject: OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO
On Wed, 2012-05-09 at 20:38 -0400, gene heskett wrote:
computers as we know them now, were still a decade in
the future, this
was the '70's.
I was aware of this, when I wrote about the computer.
On Thu, 2012-05-10 at 08:00 +0000, Fons Adriaensen wrote:
Your mentor is missing the point that even for a
switched mode PSU the
input is 50 or 60 Hz, and *something* has to store enough energy to bridge
the gaps between half cycle peaks. So you'll get mains harmonics anyway,
just as with a linear PSU.
They also cause parasitic frequencies for the mains.
- Ralf
4517
days inactive
4520
days old
linux-audio-user@lists.linuxaudio.org
11 comments
4 participants
participants (4)
-
Arnold Krille -
Fons Adriaensen -
gene heskett -
Ralf Mardorf