Hi im kinda new at this so if you need more info just say...
I got an repair, i want to do on an OLD NEC pc, the Powersupply is faulty and its a mini atx so i really need to repair it and not replace.
the Powersupply was dead. i reaplaces one of the caps2200 uf 10v, now the powersupply starts and dies again.
can anyone help me with this?
Kind regards
I got an repair, i want to do on an OLD NEC pc, the Powersupply is faulty and its a mini atx so i really need to repair it and not replace.
the Powersupply was dead. i reaplaces one of the caps2200 uf 10v, now the powersupply starts and dies again.
can anyone help me with this?
Kind regards
Most PC power supply need load to function. If you are trying to test the PS without a load, then it will do what you experience, shutdown after a second or less. If you don't want to connect it to a motherboard try connecting some 1-2Watt resistors in the 50, 100 ohms range on the 5V and 12V connections. Most of the time this works, Some of the more expensive PS actually have multiple regulators which prevents this method from working, unless you connect all many more resistors.
thanx, will check the tripping protection, dint think of that. *facepalm* i tested it with load aswell, both ways it does the same thing, if i test the voltage when it start it goes on and off, then i unplug and it does the same, really sounds like the tripping protection, i will check it out on monday. thanx for the advice!
On all the power supplies i've seen in the last 5 years their internal fan is enough load for them to start.
Almost any power MOSFET (enhancement type) will measure as a drain to source short when the gate is charged above 3 to 5V. The short should disappear completely when the gate is discharged to 0V, leaving just the body diode.
Using lower gate voltages, like 2V from the diode test function of a multimeter, will only turn on most MOSFET partially (appearing as an high d-s resistance or a weak current sink), and won't be enough to turn on some at all.
The diode test function of most multimeters comes quite handy for semiconductor testing, it usually works just as 2mA current source flowing from one probe to the other, and the display shows the voltage drop produced on whatever you test by those 2mA, as long as it's below 2V.
Using lower gate voltages, like 2V from the diode test function of a multimeter, will only turn on most MOSFET partially (appearing as an high d-s resistance or a weak current sink), and won't be enough to turn on some at all.
The diode test function of most multimeters comes quite handy for semiconductor testing, it usually works just as 2mA current source flowing from one probe to the other, and the display shows the voltage drop produced on whatever you test by those 2mA, as long as it's below 2V.
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thanx, then there is something wrong somewhere on the line if that mosfet is working, i took it out and power supply works fine...its part of the protection.. hahah just hope it wont explode or something. thanx for telling me a bit more about Mosfets, i appreciate it im starting to learn myself more about switch mode supply's because most of the amps i work on nowadays got the switch mode's, and i hate not being able to fix it.
im starting to learn myself more about switch mode supply's because most of the amps i work on nowadays got the switch mode's, and i hate not being able to fix it.- Status
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