In these case there are few Possibilities.That can cause such problems.
First of all before beginning your test,please confirm that your SMPS is working.
SMPS is called Power supply.
If the Smps is not working properly,please try with another working Smps and see if all goes well.
If the Smps is working and in good condition and still the issue is same as before" MOTHERBOARD DEAD" then follow the solutions mentioned below.
REASONS & SOLUTIONS FOR WHY MOTHER BOARD IS DEAD:------
REASON 1) ICH RTC crystal is open.Near ICH there is 32K RTC.If these RTC goes open,the motherboard will not turn ON.
Solution 1) If RTC for ICH is open,then Remove the RTC and Short its two connected point on motherboard track by tweezer and then see,if mother board starts by shorting the 32K RTC,then its faulty related to RTC Crystal.
The RTC has to be replaced.
Solution 2) Test the CMOS battery,its a silver color steel body round battery.If these battery goes weak or looses its charge then,these battery has to be replaced.Replacing these battery will solve the problem.
REASON 3) No ATX Power Good voltage ( + 5 Volts) on Super I/O Chip.
Solution 3) Jumper the Pin of Grey wire SMPS molex & ATX power pin of Super I/O Chip.
REASON 4) No +5 Volt on ON/OFF switch.
Please Note:--- ON/OFF switch is connected on PSON Pin of Super I/O chip.
Solution 4) Jumper the +5 Volt pin of SMPS power connector to the positive pin of ON/OFF switch.
REASON 5) SMPS Connector molex is ground.
Solution 5) In these case replace faulty capacitors.If any of capacitor gets ground,all connecting capacitor will show ground.In that case the capacitors needs to be checked one by one.The capacitor has to be removed from board and checked,to confirm if its dead/open/short or working.
SMPS connector getting ground is possible but very rare.
In these case there are few possible parts to be checked.
First there are few components which accepts power from SMPS connector.
The Components Like: RAM Power Supply Chip,PWM chip, Regulators for ICH, Regulators for MCH, PWM section High side Mosfets,Ram Power Section Mosfet,Operationa; Amplifier( OPAM),etc etc.
So including capacitors, if all or Any of these components become ground then automatically the SMPS connector will be ground at its positive PINS.
REASON 6) A faulty Super I/O Chip.
Solution 6) Get the datasheet for Super I/O chip.
If the voltage IN,Voltage OUT,power good voltages are not satisfactory,then its issue with super I/O chip and it has to be replaced.
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When the Desktop motherboard gets dead,at these time these are most possible faults and reasons that can cause no power to motherboard.Testing and inspecting these possibilities will help you to confirm the fault and you can get the problem repaired in that way.
If i miss any other reason and solution for Dead Motherboard issue,then please dont hesitate to share these here.
So that all others can get more benefit of these motherboard troubleshooting article.
Thanks.
