About Switch on AT power supply
錡金輝
I have a AT power supply. I would like to use it as an external power
supply (i.e No connection to the motherboard). How can I switch it on?
Regards,
Andrew Yee
_______________________________________________________________________
Name : Yee Kam Fai (錡金輝) ^__^
Dept. : Electronic Engineering
Michael Fung@cse.cuhk
> Dear All,
> I have a AT power supply. I would like to use it as an external power
> supply (i.e No connection to the motherboard). How can I switch it on?
> Regards,
> Andrew Yee
Dear Andrew,
I have encountered some models that may need a dummy loading to make the
switching circuit work. You may try inserting a resister across one of the +5V
and GND wires. Beware to estimate the adequate resistance needed.
p.s. Try at your own risk and beware of high tension!
Cheers,
Mike
ftp
> I have a AT power supply. I would like to use it as an external power
> supply (i.e No connection to the motherboard). How can I switch it on?
just connect to power supply and turn on the switch. (the swithc attached
in your case)
> Regards,
> Andrew Yee
> _______________________________________________________________________
> Name : Yee Kam Fai (錡金輝) ^__^
> Dept. : Electronic Engineering
--
ftp
> In cuhk.forum 錡金輝 <s98...@ee.cuhk.edu.hk> wrote:
>> Dear All,
>> I have a AT power supply. I would like to use it as an external power
>> supply (i.e No connection to the motherboard). How can I switch it on?
>> Regards,
>> Andrew Yee
> Dear Andrew,
> I have encountered some models that may need a dummy loading to make the
dummy loading???? AT火牛好似冇d咁o既o野喎
> switching circuit work. You may try inserting a resister across one of the +5V
> and GND wires. Beware to estimate the adequate resistance needed.
> p.s. Try at your own risk and beware of high tension!
> Cheers,
> Mike
--
Michael Fung@cse.cuhk
>>> Regards,
>>> Andrew Yee
>> Dear Andrew,
??? AT火牛好似冇d咁o既o野喎
>> Cheers,
>> Mike
I know what you are referring to. ATX Power Supply needs a mother board switch
to be turned on, this is a well-known issue around the mix-and-match circle.
However, I was referring to a characteristic of the AT Power Supply systems.
Most of such circuitries are designed around the "switching power supply"
model. Optical couplers and other isolating circuits are involved. I have
once met a model which need what I explained. Without a loading (real or
dummy), the transformer refuses to work.
To be frank, I am an outsider and know little about electronics. However, I'd
like to simply share what I've met before and hope that this two cents can help
Andrew.
Regards,
Mike
錡金輝
I have done the experience mentioned by Michael Fung. I have connected a
dummy loding (You can connect it with HD, HD's Fan, Floppy), and then it
can work. If there is NO external loading, the AT power supply can't work
indeedly! The main reason is due to that the power supply is the
"Switching Mode Power Supply". It can't working without any loading. (If
there is a switch connected to the supply, it can work without external
loading => just switch it on)
Thanks Michael Fung for providing such useful information for me!
Regards,
Andrew Yee
Regards,
ftp
> Dear All,
> I have done the experience mentioned by Michael Fung. I have connected a
> dummy loding (You can connect it with HD, HD's Fan, Floppy), and then it
> can work. If there is NO external loading, the AT power supply can't work
What is the meaning of doen't work? Will the internal fan of the power
supply turn on if you don't connect the external load? Or you means there
is no voltage output on any connect if there is no external load?(You use
a voltmeter to test it?)
> Regards,
> Andrew Yee
> Regards,
> Andrew Yee
--
Michael Fung@cse.cuhk
You're welcome :>
Cheers,
Michael
Michael Fung@cse.cuhk
> In cuhk.forum 錡金輝 <s98...@ee.cuhk.edu.hk> wrote:
>> Dear All,
>> I have done the experience mentioned by Michael Fung. I have connected a
>> dummy loding (You can connect it with HD, HD's Fan, Floppy), and then it
>> can work. If there is NO external loading, the AT power supply can't work
> What is the meaning of doen't work? Will the internal fan of the power
> supply turn on if you don't connect the external load? Or you means there
> is no voltage output on any connect if there is no external load?(You use
> a voltmeter to test it?)
According to my experience and memory, even AC power is attached and 220V
switch is turned on, neither the internal ventilating fan nor any output low
voltage power pins show activity. Situation changes when you insert some
loading across any low power output pin and the output ground.
Andrew has got a brilliant solution: insert a mini switch (and possibly a LED
with a 330 Ohm loading) across the +5V and the GND. The switch acts as an
activator.
Cheers,
Michael