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In article , Glenn Richards
wrote:
w_tom wrote:

There is good reason to leave a system on so as to not excessivly
power cycle it. And then we apply numbers. Amazing how numbers
expose junk science reasoning. For example, power switch is typically
rated for 100,000 cycle: seven times every day of the year for ....
39 years. IOW worry about something that is totally irrelevant.

"junk science"... so how come when I just turned on my Audiotron there
was a loud bang and a smell of smoke? The power supply has blown... the
exact same thing happened to my other Audiotron a few months back (a
replacement PSU fixed it).

I suspect the answer may be "junk engineering" :-) ...although that is a
harsh phrase, and I'd need to know more to be sure. However, the designer
should know what surge currents, etc, arise when the unit is switched on,
and choose components and a design that reliably deals with this.

The unit has been running fine for months, it was only turned off while
I moved it to a new location.

Given what you say, I can understand why you are wary. However my
inclination would be either to get the design modified, or change to
something that was better designed and made. Not to assume behaviour like
this was either acceptable or a 'norm' for well designed and made
equipment.

Since you often report your anecdotes, I will recount one of my own...

Many years ago, when I joined 'Armstrong' they had two general tasks for
me. One was to develop an entirely new amplifier, etc. The other was to
re-examine their existing range to see if it could be 'improved'.

I noticed that the existing 600 range amplifier units had a 'thermal delay'
in the PSU. This was a series resistor shunted with a switch. The switch
was a bimetallic strip, with a heater element. The arrangement meant that
when the unit was turned on from 'cold' the initial inrush had to go
through the resistor. However after about 10-20 seconds the heater operated
the bimetallic switch, and the resistor was bypassed.

I was told this switch was unreliable, but seemed to be essential otherwise
the sets might fail. Yet it was clear that many other manufacturers didn't
employ anything like it in their PSUs and did not seem to have a problem.

It cost a fair bit. It also tended to alarm some purchasers since the first
few times a new amplifier was switched on the heating element tended to
issue a smell like burning, and even sometimes a whisp of smoke!

Investigating, I found that the switch was present only because the diodes
chosen for the PSU rectifier had far too low a surge current rating. So I
changed to a much higher surge rating for the diodes and removed the
switch. The extra cost of the diodes was trivial compared with the saving
from not needing a switch.

The calls from new owners worried about the 'burning' vanished. The number
of sets returned for PSU problems also vanished.

All this required was to ensure that those components affected by the
switch on process were chosen to meet the requirements.

The root of the above problem was partly that the orginal designer did not
really fully understand the properties of solid state devices, so didn't
fully take the relevant factors into account. He was very skilled and
experienced with valves - where the time taken to warm the rectified valve
leads to different behaviour. But the failure or stress modes of solid
state devices were outwith his experience. His valve designs gave no
equivalent problems, because he understood how to design them so that they
didn't.

The experience was useful for me. It meant that when I designed a new (700)
amp I could ensure that although the switch-on surge was of the order of
100A, the design was reliable. I've been using two 600s and two 700s for
the last 20-30 years. No failures in their PSUs or related to switchon.
Indeed, FWIW, one of my main personal concerns at the time was that units
would be reliable in use. This benefits both the customers and the company
in my view.

None of the above is 'rocket science'. It just requires the designer to be
aware of what they are doing, device specs, and a maker who will then use
the required components - not try to cheese-pare by using something
'cheaper' which may cost more in the long run!

Thus if your 'Audiotron' unit has a specific failure mode at switch-on I'd
be inclined to view its design with some caution. If the circuit diagrams,
etc, are available, let us know. We may be able to spot a 'fix'. However I
can't say anything more specific as I am afraid I don't know anything about
it.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

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On Sun, 20 Aug 2006 08:53:26 +0100, Jim Lesurf
wrote:

Many years ago, when I joined 'Armstrong' they had two general tasks for
me. One was to develop an entirely new amplifier, etc. The other was to
re-examine their existing range to see if it could be 'improved'.

Those quote marks again!

You use them (I quote):

"To recognise the fact that the 'newness' may simply be a matter of
moving the deck chairs around. So may be 'new' in name, but not always
in terms of useful performance."

Is that what Armstrong wanted?

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In article , Laurence Payne
lpayne1NOSPAM@dslDOTpipexDOTcom wrote:
On Sun, 20 Aug 2006 08:53:26 +0100, Jim Lesurf
wrote:

Many years ago, when I joined 'Armstrong' they had two general tasks
for me. One was to develop an entirely new amplifier, etc. The other
was to re-examine their existing range to see if it could be
'improved'.

Those quote marks again!

In this case because the actual company had various names from "Armstrong
Audio", to "Armstrong Wireless and TV" during its history. Often having
more than one trading name at a given time. Since it didn't seem relevant
to explain this for my anecdote I omitted the details, but I though it
possible some people would actually recall them as something like
'Armstrong Audio', but that others might be puzzled by this as they
recalled some other name.

I was therefore trying to avoid giving detail that seemed irrelevant. But
since I have now explained I would be happier to use the word without
the quote marks.


You use them (I quote):

"To recognise the fact that the 'newness' may simply be a matter of
moving the deck chairs around. So may be 'new' in name, but not always
in terms of useful performance."

Is that what Armstrong wanted?

Afraid I have no recollection of a company policy for the word 'new'. :-)
That said, the company did tend to develop and improve products in
production *without* actually changing the advertising or altering
the model number. So a 600 range set bought near the end of the
period during which they were made would have looked like one of
the early models, but the actual performance was better in various
ways. Sold on the basis of the same model numbers and specs that
applied to the initial version, though.

I used the quote marks around the 'new' and 'newness' above to
indicate that these were the terms whose actual meaning I was discussing.
Indeed, 'newness' seems to me to be a vague term.

I had assumed the context made this clear. My point is that a word like
'new' is often employed simply as an attractive label by advertisers
even when the actual functional product inside the package has no
real novelty whatsoever in terms of performing the task for which the
purchaser has in mind.


Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

The best upgrade you can buy for your system...
 

On Sun, 20 Aug 2006 14:34:20 +0100, Jim Lesurf
wrote:

The other
was to re-examine their existing range to see if it could be
'improved'.

Those quote marks again!

"Improved" was what I was looking at.

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Jim Lesurf wrote:

Thus if your 'Audiotron' unit has a specific failure mode at
switch-on I'd be inclined to view its design with some caution. If
the circuit diagrams, etc, are available, let us know. We may be able
to spot a 'fix'. However I can't say anything more specific as I am
afraid I don't know anything about it.

For those that don't know, the Audiotron is a device made by Turtle
Beach that looks similar to a tuner, but on the back has power, audio
L/R, optical SPDIF and Ethernet connectors. I'm sure you can guess the
rest. (If you can't - it's a hi-fi separate sized networked MP3 player.)

The PSU in these units seems prone to failure, it's a Globtek ITU
open-frame switch mode device. I've now had two fail in exactly the same
way. Turtle Beach couldn't (or wouldn't) help as the product is now
discontinued. Contacted Globtek three times and got absolutely no
response...

Fortunately Maplin do a wall-wart SMPSU for about 15 quid, the 2-pin
connector on this fits exactly onto the 2-pin header on the main board
of the Audiotron. I've already repaired one unit, now I know of a
compatible part repairing the second will be easy.

The first unit was 2 years old when it failed, the second 2 1/2 years
old. When I opened the first one up the PSU did seem to be made rather
cheaply, so of course I was expecting the second unit to fail at any time.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

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When computer was turned off, then it did not restart. Clearly this
demonstrates power cycling causes failure. Yes, if using junk science
reasoning based only upon observation. Instead use logical facts to
create a conclusion. First learn the reasons why. In normal
operation, a pullup resistor failed. With a failed pullup, then boot
circuit for a voltage regulator did not restart a power supply. Power
cycling did not cause this failure. Resistor was damaged in normal
operation. But those who just know, instead, did classic junk science
reasoning. Because a power supply did not restart during a power
cycle, then clearly failure must have been created by power cycling.
Reality - discover first why something failed - demonstrates that
normal operation created the damage. Learn reasons why before drawing
a conclusion is a concept taugh in science class. Junk scientists
don't first learn technical facts. They know only upon observation.

Same junk science also proves that life could be created by
spontaneous regeneration. Another example of observation sufficient to
prove a fact: science be damned.

Power cycling is has been declared destructive because component
analysis was not performed. What part failed, when and why? Without
that answer, then declarations about destructive power cycling are only
classic junk science proclamations.

Normal operation caused pullup failure. But junk science declared
the failure due to power cycling because a human used only observation
as proof; technical facts be damned.

Glenn Richards wrote:
"junk science"... so how come when I just turned on my Audiotron there
was a loud bang and a smell of smoke? The power supply has blown... the
exact same thing happened to my other Audiotron a few months back (a
replacement PSU fixed it).

The unit has been running fine for months, it was only turned off while
I moved it to a new location.

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In article , Laurence Payne
lpayne1NOSPAM@dslDOTpipexDOTcom wrote:
On Sun, 20 Aug 2006 14:34:20 +0100, Jim Lesurf
wrote:

The other
was to re-examine their existing range to see if it could be
'improved'.

Those quote marks again!

"Improved" was what I was looking at.

The explanation is parallel to the others I gave.

The term included various things, some of which would be apparent to a
customer, others not. For example, in some cases I found a component of
equal performance but which was smaller or cheaper. This did not affect the
performance, reliability, or appearance of the set, but helped the company
stay in business. In other cases it was a change to something like a larger
value o/p capacitor and a change of o/p devices, increasing the current
levels the amp could provide and extending the bass.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

The best upgrade you can buy for your system...
 

w_tom wrote:

When computer was turned off, then it did not restart.

It's not a "computer", it's a hi-fi component. The PSU failed when the
unit was powered up - due to the inrush current at switch-on.

Same reason that light bulbs nearly always fail at switch-on - the
inrush current hitting a cold filament causes thermal shock which can
fracture the filament.

When I did stage lighting a few years back we were told that UNDER NO
CIRCUMSTANCES should you turn on a high powered stage light straight to
full brightness, and that if you ever used the "blackout" switch (kills
all lights) you must ALWAYS pull the master faders down to zero before
cancelling blackout. Why? Because putting full power through a cold
filament on a big-ass stage light will cause the filament to fail... and
unlike a domestic GLS bulb where you get a "ping" and darkness, with a
stage light you'll get a loud bang and a shower of glass and sparks!

DMX dimmer racks don't have a "pre-heat" setting for nothing. When the
channel brightness (whether channel or master fader) is set to 0 the
dimmer rack is actually passing a small amount of current through the
light to warm up the filament - to avoid the above scenario.

Normal operation caused pullup failure. But junk science declared
the failure due to power cycling because a human used only
observation as proof; technical facts be damned.

Inrush current at switch-on caused the failure. But had the unit been
left powered up this would not have occurred (at least not at this
point). Power cycling wasn't the direct cause of the failure, but that
inrush current happens whenever the unit is powered up. And every time
switch-on occurs the particular component that failed is placed under
stress, shortening its life.

--
Glenn Richards Tel: (01453) 845735
Squirrel Solutions http://www.squirrelsolutions.co.uk/

IT consultancy, hardware and software support, broadband installation

The best upgrade you can buy for your system...
 

"Glenn Richards"


It's not a "computer", it's a hi-fi component. The PSU failed when the
unit was powered up - due to the inrush current at switch-on.


** Pure supposition.


Same reason that light bulbs nearly always fail at switch-on - the inrush
current hitting a cold filament causes thermal shock which can fracture
the filament.


** Only a BADLY worn or damaged lamp filament fails at switch on.



When I did stage lighting a few years back we were told that UNDER NO
CIRCUMSTANCES should you turn on a high powered stage light straight to
full brightness, and that if you ever used the "blackout" switch (kills
all lights) you must ALWAYS pull the master faders down to zero before
cancelling blackout. Why?


** Simple - the COMBINED inrush surge current of many COLD lamps coming
on together will instantly trip the circuit breakers in the AC supply. All
goes dark.

Any other story is purest ******** !!!



Because putting full power through a cold filament on a big-ass stage
light will cause the filament to fail.


** ******** !!!!!!!!!


DMX dimmer racks don't have a "pre-heat" setting for nothing.


** They have it to make large lamps become bright faster.

Plus to reduce the surge current when multiple lamps are "flashed" on.


When the channel brightness (whether channel or master fader) is set to 0
the dimmer rack is actually passing a small amount of current through the
light to warm up the filament - to avoid the above scenario.


** ******** !!!!!!!!!

They have it to make large lamps become bright faster.

Plus to reduce the surge current when multiple lamps are "flashed" on.


Inrush current at switch-on caused the failure.


** Not with ANY competently designed equipment.



Glenn Richards Squirrel Solutions


** ROTFL.

More like Duck Solutions, from a waddling Quack.





......... Phil

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In article , Glenn Richards
wrote:
w_tom wrote:

When computer was turned off, then it did not restart.

It's not a "computer", it's a hi-fi component. The PSU failed when the
unit was powered up - due to the inrush current at switch-on.

Same reason that light bulbs nearly always fail at switch-on - the
inrush current hitting a cold filament causes thermal shock which can
fracture the filament.

Just as a hifi component isn't a computer, nor is it an incandescent lamp.
Although I fear that some spectacularly poor designs may seek to emulate a
lamp - or even fireworks. :-)

When I did stage lighting a few years back we were told that UNDER NO
CIRCUMSTANCES should you turn on a high powered stage light straight to
full brightness, and that if you ever used the "blackout" switch (kills
all lights) you must ALWAYS pull the master faders down to zero before
cancelling blackout.

But an audio component is not a stage light. Nor a pop-up toaster, or many
other items you could list. Do not put your mp3 player into a pop-up
toaster and try to use it as a 'dock' for the player. And do not accept
that an item of audio equipment shall behave like a toaster. ;-

Why? Because putting full power through a cold
filament on a big-ass stage light will cause the filament to fail... and
unlike a domestic GLS bulb where you get a "ping" and darkness, with a
stage light you'll get a loud bang and a shower of glass and sparks!

DMX dimmer racks don't have a "pre-heat" setting for nothing. When the
channel brightness (whether channel or master fader) is set to 0 the
dimmer rack is actually passing a small amount of current through the
light to warm up the filament - to avoid the above scenario.

Ahhh... This all brings back happy memories of when I used to do stage
lighting and we used a broomstick as the 'bank fader control'... :-) But
I'm afraid this has nothing to do with audio as such.

Normal operation caused pullup failure. But junk science declared
the failure due to power cycling because a human used only observation
as proof; technical facts be damned.

Inrush current at switch-on caused the failure.

Having this happen more than once is, as has already been pointed out, an
indicator of poor design or manufacture. This is the root of the problem.
Thus to avoid similar problems in future, choose hifi components that are
better designed and built. Then you can use the power switch with more
confidence. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html