AcBel 450W cannot turn on ?

[wan901]

Guys i have a PSU AcBel 450W that problem cannot be turn on when plugged to motherboard..... when i sorted it from green to black it can powered on... is this supposed to caps or anything else related ? give me some advice ^_^

[Spacedye69]

Re: AcBel 450W cannot turn on ?

Since it turns on manualy, I would think it is more of a motherboard issue.

[wan901]

Re: AcBel 450W cannot turn on ?

lol.... i dont think so its the board.... well now i know it.... its becuz of the switch at the back was loosen .... =_= ... now i really need to mod the PSU lol 0_0!

[wan901]

Re: AcBel 450W cannot turn on ?

O.O ... Guys .... i don't think its the mobo ....or my PSU swicth (at back) ....juz now .... i used my PC around 15minutes .....my PC suddenly power off itself...then cannot turn on anymore ...light indicator showing power good .... ?_? i really confuse now... anyone had any idea ??

[Brian C]

Re: AcBel 450W cannot turn on ?

Abang Wan901, not sure what's ur system configuration... It could be due to supply overload.

[ ...light indicator showing power good .... ]

is this the LED on ur mobo ? It is Standby 5V, not POWER GOOD signal. Power good signal is from pin (8) of 20-pin/24-pin connector (grey color wire).
Power Good is only available upon power on....

Could be bad e-cap... if ur PSU is no longer in warranty. I suggest u to open it and take a look inside...

[Krankshaft]

Re: AcBel 450W cannot turn on ?

Jumper the supply to turn it on and measure the 12 volt (yellow wire) and 5 volt (Red Wire) rails are they excessively low?

Or does the supply just make a high pitched whine when you try to start it up?

If so thats a protection circuit kicking in reducing the switching frequency of the supply.

I wouldn't get to concerned with the Power Good signal some cheap PSU manufacturers just tie that wire to the 5 volt rail in other words unless the PSU really took a dump and doesn't supply voltage at all its useless.

Good PSU manufacturers have a Power Good Generator IC that the wire is tied to and the IC monitors the supply voltages if the voltages are good it sends out the 5 volts through the wire. If a voltage is wrong it cuts off the 5 volt supply which shuts the supply down in a case of an under or overvoltage condition.

In any case I'd pop it open to check for any bulged caps inside.

[Krankshaft]

Re: AcBel 450W cannot turn on ?

10 minute post edit you are the bain of my existence .

If the Fuse, Line Rectifier, Switching Mosfets, Secondary Rectifiers, Optoisolator, and Caps check out and the supply is still dead its probably a Bad PWM or Power Good IC or one of their surrounding components.

Without a scope to monitor the PWM IC for a drive waveform this is the only way to troubleshoot them.

I have a scope but there is no way I'd ever hook it up to this line powered equipment without an isolation transformer. I've gotta just break down and buy one already.

I recently brought back a switcher for my old D-Link wireless B router that took a dump during a series of about 4 brownouts in the summer. Everything inside checked out good so I replaced the PWM IC and we're back in business.

I guess the IC got pounded with too much startup voltage and the internal regulator just blew. The IC had no signs of case damage on the outside.

[wan901]

Re: AcBel 450W cannot turn on ?

yeah i open the psu.... no sign of bad caps inside ... +_+ but i see a brand Taepo on 200V 820uF caps 0_0