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PSU voltage instability

S

Slater

Jan 1, 1970
0
Hello, I have an ATX power supply. I tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
 
S

Sjouke Burry

Jan 1, 1970
0
Slater said:
Hello, I have an ATX power supply. I tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
Often only one of the voltages, for example the the 5volt, is regulated,
the others are determined by transformer ratio, and are more
load dependent.
The 12v is usually one of the "raw" voltages, and as such is allowed to
vary quite a lot.
 
S

Slater

Jan 1, 1970
0
Jeff Liebermann said:
Right. All ATX power supplies are identical. Maker and model please?

Maker: Whatsup
Model: ATX-400W P4

My concern is not how off the voltage is, it's the instability: is it
normal? The voltage changes depending on the load. The PSU inside my
PC doesnt do this.
Some power supplies are junk.
Perhaps mine is in that league!
 
D

David Nebenzahl

Jan 1, 1970
0
"Jeff Liebermann"
[O.P. wrote:]
I tested it with a CD ROM drive attached and noticed that the 12V
rail gives me a lower voltage when the CD tray is moving (11.79V
against the usual 11.87V). Could this be due to bad capacitors?

If you're getting 10mv accuracy with your DVM, you must have a
decent way of calibrating your instrument to that resolution. 100mv
accuracy is more reasonable.

** How pedantic and idiotic !!!

The OP is only asking about the small DROP in voltage he measured under
load - which NOT dependant on calibration or accuracy of the meter.

The LINEARITY of most DMMs is of a very high order - 1 part in 1000 is
typical.

Wellll ...

Isn't the correct answer here "don't worry about it"?

I mean, the O.P. is reporting a voltage drop of 80 mV. Compared to a
reference of 12 volts (nominal), that's ... lessee ... 0.67%. Much less
than any *rated* regulated variation of any computer power supply, right?


--
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http://88.80.13.160/
 
P

Phil Allison

Jan 1, 1970
0
"David Nebenzahl"
Phil Allison spake thus:
"Jeff Liebermann"
[O.P. wrote:]

I tested it with a CD ROM drive attached and noticed that the 12V
rail gives me a lower voltage when the CD tray is moving (11.79V
against the usual 11.87V). Could this be due to bad capacitors?

If you're getting 10mv accuracy with your DVM, you must have a
decent way of calibrating your instrument to that resolution. 100mv
accuracy is more reasonable.

** How pedantic and idiotic !!!

The OP is only asking about the small DROP in voltage he measured under
load - which NOT dependant on calibration or accuracy of the meter.

The LINEARITY of most DMMs is of a very high order - 1 part in 1000
is typical.

Wellll ...

Isn't the correct answer here "don't worry about it"?


** NO !!

The pig arrogant arsehole made a false point.



..... Phil
 
P

Phil Allison

Jan 1, 1970
0
"Jeff Liebermann is a FUCKING ****"

Pedantic
-adjective
1. ostentatious in one's learning.
2. overly concerned with minute details or formalisms, esp. in
teaching.


** More fucking, idotic pedantry.

Only thing this stinking POS is any good at.

Ummmm... ok.


** Go **** your mother.



( Snip more pedantic, fucking SHIT )

The question was whether the power
supply was defective, which in my opinion is more a matter of keeping
the output voltage within the specifications (with any load).

** More pedantic BOLLOCKS.

Linearity is usually +/- 1 bit or LSB. If it's a 3 1/2 digit cheapo
DVM, with a full scale reading of 1999, it probably has 10 bit A/D
converter.

** ROTFLMAO !!!!!

Wot a FUCKING MORON.

Regular DMMS do not use conventional A-D converters.

They use "dual slope integration " - ie an analogue technique.

The "digital" bit is the fucking display.

IMBECILE !!!!!!!!!!!

1 bit error = 20.0 V / 2000 = +/- 10 mv error.
For an 80 mv difference, there's a 40 mv uncertainty due to
non-linearity (+/-10 mv error for the no-load, and another +/-10 mv
for the loaded readings).

** Crapology.

The same meter is used and so the only error is the +/-1 bit display
uncertainty.

GO **** YOURSELF you STINKING PEDANT !!



..... Phil
 
P

Phil Allison

Jan 1, 1970
0
"Jeff Liebermann = a lying AUTISTIC ASSHOLE "


** Drop dead you pathetic fuckwit.




...... Phil
 
D

David Nebenzahl

Jan 1, 1970
0
"Jeff Liebermann = a lying AUTISTIC ASSHOLE "

** Drop dead you pathetic fuckwit.

OK, so my guess is, oh, another week or so before Phil posts a calm,
reasonable (and correct) message here.

Guess it takes that long for the meds to take effect ...


--
How To Access Wikileaks

These sites are still up as of 12/3/10:

http://wikileaks.de
http://wikileaks.fi
http://wikileaks.nl
http://wikileaks.eu
http://wikileaks.pl

And these IP addresses can be used:

http://213.251.145.96/
http://88.80.13.160/
 
P

Phil Allison

Jan 1, 1970
0
"David Nebenzahl is Donkey Brained Troll "
OK, so my guess is, oh, another week or so before Phil posts a calm,
reasonable (and correct) message here.


** Shame is pal, EVERY SINGLE TIME I do just that - a bunch of
fucking, autistic RETARDS like YOU come along afterwards and try to piss on
it.

Same all over damn usenet -

nothing but FUCKING TROLLS !!!!!!!!!!!


..... Phil
 
M

Meat Plow

Jan 1, 1970
0
"David Nebenzahl is Donkey Brained Troll "


** Shame is pal, EVERY SINGLE TIME I do just that - a bunch of
fucking, autistic RETARDS like YOU come along afterwards and try to piss
on it.

Agree- somewhat.
Same all over damn usenet -

Comes with the territory Phil
nothing but FUCKING TROLLS !!!!!!!!!!!

Including you.
 
P

Phil Allison

Jan 1, 1970
0
"Jeff Liebermann = a lying AUTISTIC ASSHOLE "



** Drop dead you pathetic FUCKWIT !!!




...... Phil
 
D

David Nebenzahl

Jan 1, 1970
0
P

Phil Allison

Jan 1, 1970
0
"David Nebenzahl


** This vile, autistic **** need one in the head.



...... Phil
 
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