[SOLVED] Would a reverse polarity CPU EPS-12v connector kill the motherboard as well as the cpu?

[SpookyWeeb]

I was given a modular power supply by a friend to use in a pc im building. he didnt realise that modular cables are nonstandard and gave me one intended for a different power supply. I realized this while trying to troubleshoot why the pc wouldnt post. ive already replaced the processor and remedied the problem with the power cable but it still wont post. is the motherboard dead too?

 

[Lutfij]

Welcome to the forums, newcomer!

The simple answer is yes, it can. Might want to pass on the make and model for the PSU and the cables that you were given, since not all PSU's will have the same pinout for every modular PSU on the market.

 

[arif1752002m4a1]

I WILL SAY NO...
reason.. -- when you put eps connector in reverse.. you are shorting 12v ESP rail to ground... (ESP ground will float because its connected with 12V CPU.. which cant conduct gnd back to esp port..) via 24 Pin Ground connector.. and many Modern PSUs have SCP.. short circuit protection.. and that will not let PSU to push enough power to burn PCB Tracks...

although in rare cases you might end up in killing PSU, Motherboard connnector etc etc... But Its unlikely that can serious damage to Motherboard..

 

[USAFRet]

I WILL SAY NO...
reason.. -- when you put eps connector in reverse.. you are shorting 12v ESP rail to ground... (ESP ground will float because its connected with 12V CPU.. which cant conduct gnd back to esp port..) via 24 Pin Ground connector.. and many Modern PSUs have SCP.. short circuit protection.. and that will not let PSU to push enough power to burn PCB Tracks...

although in rare cases you might end up in killing PSU, Motherboard connnector etc etc... But Its unlikely that can serious damage to Motherboard..

"I WILL SAY NO..."
...is a pretty categorical statement of "never".

Later, you state:
" But Its unlikely..."
So...it might happen.


And of course, we out here have no idea of the PSU involved here.
There are absolutely crap devices around, that lack the needed protections.

 

[arif1752002m4a1]

"I WILL SAY NO..."
...is a pretty categorical statement of "never".

Later, you state:
" But Its unlikely..."
So...it might happen.


And of course, we out here have no idea of the PSU involved here.
There are absolutely crap devices around, that lack the needed protections.

Last Statement sounds like.. Ok..
there are many many reasons why a PSU can kill a motherboard while its plugged in a wrong way.. and there are many many reasons why it cant kill a motherboard... But also i kept PSU safety in mind... so that thing plays a big role why i said No.. it cant kill a psu...

other Reason... When PSU starts... or any Switch Mode Power Supply. Initial Current Spike in very high in primary side of transformer because of High output Capacitance (Output Capacitors).. which is also kept in mid during designing a PSU.. there are certain limits a PSU can detect a short or a very high power hungry device... so if we combine discharged Output caps... with shorted 12v raill.. a Dual Switch Forward PSU of capacity 650 will most likely generate close to 180 amps at secondary for very brief amount of time... which is very high for not triggering OCP....
and he is not usning a 2000-1700 watt PSU.. so that why i said.. OCP will trigger instead of properly frying Mobo.. Its about Probability...

Peace.. I am assuming a lot of stuff... while actual Parameters may be very very different from assumption..
Good Day

 

[USAFRet]

Last Statement sounds like.. Ok..
there are many many reasons why a PSU can kill a motherboard while its plugged in a wrong way.. and there are many many reasons why it cant kill a motherboard... But also i kept PSU safety in mind... so that thing plays a big role why i said No.. it cant kill a psu...

other Reason... When PSU starts... or any Switch Mode Power Supply. Initial Current Spike in very high in primary side of transformer because of High output Capacitance (Output Capacitors).. which is also kept in mid during designing a PSU.. there are certain limits a PSU can detect a short or a very high power hungry device... so if we combine discharged Output caps... with shorted 12v raill.. a Dual Switch Forward PSU of capacity 650 will most likely generate close to 180 amps at secondary for very brief amount of time... which is very high for not triggering OCP....
and he is not usning a 2000-1700 watt PSU.. so that why i said.. OCP will trigger instead of properly frying Mobo.. Its about Probability...

Peace.. I am assuming a lot of stuff... while actual Parameters may be very very different from assumption..
Good Day

And I personally had a janky PSU die, and kill the motherboard as it went to PSU heaven.
Corsair CX600 green label.

So yes, a PSU can absolutely kill a motherboard.

 

[Lutfij]

^ I had a similar thing happen with pretty much all units from the SMART series by Thermaltake, all of my clients ended up with busted motherboards and worse 1 dead GPU.

 

[SpookyWeeb]

The power supply is a "EVGA supernova 650 g+". I don't know what psu the imposter cable came from. Since then ive gone through with a multimeter and verified that all the voltages were correct on the cables im now using and replaced the motherboard(cpu was in the old motherboard but never subjected to the bad power) . Though the computer still wont post.