PC PSU repair help

[alyas]

Last friday night, nag dip yung power 2 times (in less than a second) bago tuluynang nawalan ng kuryente.  After that i turned of everthing and disconnected all the plugs.  In the morning when there was already power, when I switched on the pc sa front panel and then walang nangyari.  May na amoy na lang akong amoy sunog so I immediately unplugged everthing.

Is there a chance na nadale yung mobo ko?  May mga failsafe ba itong mga pc psu para di tumuloy ang voltage output sa mobo?

May pag-asa pa ba ayusin ito at ano yung possible parts na naging borken.  Upon smelling, amoy sunog yung malaking torroid transformer in the middle although walang evidence of burned marks.

The psu is a T.C. Star 550W PSU model AD-5550N2-46.

Kung medyo mahirap gawin, I don't think I still have the patience to repair this by myself.  Saan pa pwede magpa-repair ng mga pc psu?

Thanks in advance for any help and advoce.  Below are some pictures of the psu.  Maybe someone has already worked or is familiar with the design of this psu., pa help naman in triubleshooting.

[rdpzycho]

pumutok ba yung fuse? supposedly, may mga failsafe devices ang PSU para hindi maapektuhan ang CPU. overvoltage shutdown at overcurrent shutdown ang kalimitan.

kung pumutok yung fuse, malaki probability na yung MOSFET ang sira (or in some China PSU, a BJT transistor). kapag nasisira yung PSU sa test bench ko, kalimitan MOSFET or output rectifier ang nasisira.

[motion55]

Try to power up the PSU without using the mobo. You can do that if you short the green wire (pin#14) and the black wire (pin#15) of the ATX mobo connector. See if the PSU's fan are spinning. Check the output voltages if they are close to the nominal value.

I don't think the pwede masunog ang large toroid transformer sa outputs. Their main function is to balance the 5V and 12V output loads. Most likely one component nearby the toroid ang nasunog. Most likely it is the capacitors or less likely the resistors nearby. Another part na pwede masunog ay mga diodes pero pag nasira yan wala kang makuhang output. 

[jhamir]

hindi macicira ung mobo mo kya nga nauso ngaun gumamit ng isolation chopper pra my secondary na isolated..or cold part... na pde hawakan...  over voltage protect ung part kasama na ang photo coupler kadugtong ung nasa secondary part... paltan mo kung ano makita mo cira... pero bgo mo ishort ung green on gray test ka muna using 110v not 200v para mas safe...  check mo ung green wire kung my standby 5v supply ...yan ang "power on "galing mobo... na syang imamanual
switch mo... pag meron abang ka nman ng tester sa red or yellow dun na sa output dapat my 5v sa red at 12 sa yellow wire... gud luck... rem.. 110v muna ha......

[gie62]

daming capacitor na sira ah, nag leak na..

[alyas]

Thanks for all your replies.  Ipaparepair ko na lang siya sa nagrerepair talaga ... I dont have the time and patience anymore to repair this myself.

On a side note, I bought a cheap 550W psu as a replacement and powered up my pc.  Mukhang may tama yung mobo ko since hindi madetect sa power on sequence yung keyboard.  Hopefully  sana its just because of the cheap psu that cannot power up the whole pc sufficiently. 

[ahlburuto]

orig ba yang psu mo?

[alyas]

orig ba yang psu mo?

Yung broken psu ba o yung replacement?  I've already learned from experience that cheap will always mean under-rated.  Yung broken psu is a well know brand sa Taiwan and is exported as an oem psu to several well known international brand.

[rdpzycho]

actually, some China PSU's don't have the required overcurrent protection required by the ATX specification. lagi lang sa fuse nagre-rely. quality PSU's will not die if you short the outputs, pero yung mga mura at low quality, puputok ang fuse.

[alyas]

Yung broken psu ko, wala akong makitang fuse.  Kaya ako nagtataka for such an expensive psu na walang basic fuse protection?  Maybe its using one of those resettable fuses.  Ano ba ang itsura ng ganung mga resettable fuse??

[rdpzycho]

hmmm. mukhang similar siya dun sa shorted ang fuse sa board. nakakita na ako ng mga ganyang PSU, and normally protected output niyan. hindi ko alam kung meron silang ibang ginamit na fuse pero pag shorted output hindi sila nasisira. eto yung type na mostly sa secondary side ang sira like diodes.

[alyas]

Yung mga cheap psu from china/taiwan ay  talagang under rated.  My desktop pc is now working again on after disconnecting several hard disks and other peripherals from the psu.  Its still not enough though to power up my wireless keyboard/mouse.

So protected pala talaga yung mobo from psu failures.  Anyone knows where I can have the psu repaired?  Locally available psus w/ similar specs cost 4K and up.

[Ate Shey]

actually, some China PSU's don't have the required overcurrent protection required by the ATX specification. lagi lang sa fuse nagre-rely. quality PSU's will not die if you short the outputs, pero yung mga mura at low quality, puputok ang fuse.

hehehehe.. kaya nga ako yung mga branded na PSU lang ang ginagamit ko like HEC or TASK.. between the two much better ang HEC kasi minsan may mga lemon ang TASK.. pero they are both good kasi meron silang seals from CSA and UL..

[high_voltage]

Last friday night, nag dip yung power 2 times (in less than a second) bago tuluynang nawalan ng kuryente.  After that i turned of everthing and disconnected all the plugs.  In the morning when there was already power, when I switched on the pc sa front panel and then walang nangyari.  May na amoy na lang akong amoy sunog so I immediately unplugged everthing.

Is there a chance na nadale yung mobo ko?  May mga failsafe ba itong mga pc psu para di tumuloy ang voltage output sa mobo?

May pag-asa pa ba ayusin ito at ano yung possible parts na naging borken.  Upon smelling, amoy sunog yung malaking torroid transformer in the middle although walang evidence of burned marks.

The psu is a T.C. Star 550W PSU model AD-5550N2-46.

Kung medyo mahirap gawin, I don't think I still have the patience to repair this by myself.  Saan pa pwede magpa-repair ng mga pc psu?

Thanks in advance for any help and advoce.  Below are some pictures of the psu.  Maybe someone has already worked or is familiar with the design of this psu., pa help naman in triubleshooting.

Sir buntis n ung ibang capacitor sa pix eh... try to look for subtitute capacitor nalang kung marunong ka mag mold. OR/AND check mo muna ung fuse baka pumutok eh..

[1110000]

may mga fuse na bilog baka ganoon ang nakalagay saiyo kaya ndi mo makita, parang bridge type diode pero dalawa lang pin

[Dennis.]

Ako ganyan rin experience nakahanap ako ng buntis na capacitor sa katabi ng mga wire. katabi ng dalawa coil. isa lang yung . check mo rin transistor at visual kung maari pati narin diode.

speaking capacitor
May tanong rin ako may speaker ako 50watts lang nilagyan ko ng Capacitor 10uf 50v sa negative side naging matining yung tunog, mali yata ako ano ba pwedi ko gawin para medyo gumanda output nya?

[ferdie444]

Ako ganyan rin experience nakahanap ako ng buntis na capacitor sa katabi ng mga wire. katabi ng dalawa coil. isa lang yung . check mo rin transistor at visual kung maari pati narin diode.

speaking capacitor
May tanong rin ako may speaker ako 50watts lang nilagyan ko ng Capacitor 10uf 50v sa negative side naging matining yung tunog, mali yata ako ano ba pwedi ko gawin para medyo gumanda output nya?

bro,try to use non-polarized electrolytic capacitor or try to use a dividing network unit kung 3way speaker system.

[alyas]

The pictures may seem misleading.  Walang buntis or bloated caps .... I did'nt even smell of any leaked caps when the psu conked out on me.  Only the smell of burned varnish similar to the smell of an overheated and shorted transformer.  You can easily distinguish naman between the smell of a burned resistor, the smell of a leaking capacitor and the smell of a burned transformer.   Looks like I may have to really repair this myself kaya lang mukhang mahirap at ang kakapal ng mga solder tracks underneath the pcb.  Kailangan siguro ng mga 60W soldering iron just to desolder one of the mosfets.

[beginner wan]

kung pumutok yung fuse, malaki probability na yung MOSFET ang sira (or in some China PSU, a BJT transistor). kapag nasisira yung PSU sa test bench ko, kalimitan MOSFET or output rectifier ang nasisira.

this is true... yung PSU na binuksan ko, yung mosfet ang sunog eh..hehehe...

regarding sa pag-desolder.. mataas na temp ng iron ang ginamit ko. di ko alam bakit parang hirap matunaw nung mga leads eh.. 

[Ganda692002]

Yung sakin din ay Mosfet ang chunog.. Yung Mosfet para sa 3 volts..yung nagsusuply sa memory at processor.. nachugi..

10amp lang kasi yung rating nung tingnan ko yung datasheet.. at yung nakakbit na pentium 4 ay 18amps kelangan hehehe.. Umandar sya for one year pero na tsugi narin.. di na nakaya ng heatsink..