Question Cpu powers down when i plug in my HDD. Why?

[Coanski]

I added a new video card/ram/power supply to my existing setup. Everything was going well until I plugged in the power to my HDD. At this time the whole system shut down. If I unplug the power to the HDD the PC starts no problem. Any ideas?

Edit : I have tried putting all the old hardware back into the case and I'm having the same problem

 

[Phaaze88]

Did you use one of those molex to sata connectors for this HDD? Looks like this: https://www.amazon.com/SATAPOWADAP-StarTech-com-Power-Cable-Adapter/dp/B00009YFTI
What's the make and model of your power supply?

 

[Coanski]

Did you use one of those molex to sata connectors for this HDD? Looks like this: https://www.amazon.com/SATAPOWADAP-StarTech-com-Power-Cable-Adapter/dp/B00009YFTI
What's the make and model of your power supply?

I have tried both types of cables. Molex and SATA. The power supply has both available. The PSU is a OCZ MOD x stream-pro 700w

 

[Phaaze88]

Which one did you connect directly to the HDD first, prior to powering the PC on?
The regular sata power cable? EX: https://www.amazon.com/COMeap-Repla...coding=UTF8&psc=1&refRID=D0S0K3K1BFGWC4ZY0256
Or the molex-to-sata connector? EX: https://www.amazon.com/SATAPOWADAP-...ascsubtag=tomshardware-1699710136147287911-20

Did you attempt to connect the power to the HDD while the PC was on?

What is the rest of your build?

 

[Coanski]

first attempt - regular sata (new psu) power off
second attempt - regular sata (old psu) power off
3rd- regular sata (new psu, different harddrive) power off

then i tried molex with different setups all powered off

i did try plugging it in hot at this point(hope i didnt do too much damage with this silly move) to isolate what was causing the short and sure enough it powered down the system. so if i boot up without the hdd power connected, it boots fine....

i will try to obtain my specs visually but i cant access my system to check haha. thanks for taking the time to reply. much appretiated!

 

[Phaaze88]

Yeah, don't hot plug. I killed a PC once with a 4-pin fan connector.
And refrain from using molex if you can help it. They're ok to use, but they're not exactly great.
Check the back(?) of the HDD for bent or broken pins. If the PC boots fine without the HDD, then there's a short somewhere.

Are you using any of the cables from the old power supply? That's actually a bad idea. You can fry things that way.

 

[Coanski]

Yeah, don't hot plug. I killed a PC once with a 4-pin fan connector.
And refrain from using molex if you can help it. They're ok to use, but they're not exactly great.
Check the back(?) of the HDD for bent or broken pins. If the PC boots fine without the HDD, then there's a short somewhere.

Are you using any of the cables from the old power supply? That's actually a bad idea. You can fry things that way.

No not using any of the old cables with the new psu. the old psu cables are not swapable

 

[fzabkar]

TVS Diode FAQ:
http://www.hddoracle.com/viewtopic.php?f=100&t=86

 

[Coanski]

TVS Diode FAQ:
http://www.hddoracle.com/viewtopic.php?f=100&t=86

Thanks! Interesting faq. And is a definate possibility for my situation

 

[Phaaze88]

TVS Diode FAQ:
http://www.hddoracle.com/viewtopic.php?f=100&t=86

Oh wow. If that's what happened, that just further points to the PSU being bad, right?

 

[Coanski]

Oh wow. If that's what happened, that just further points to the PSU being bad, right?

Unfortunately it does. It just seems odd because the "New psu" I got was pulled out of a friends working machine when he got another one. Anyway at this point I may just bring it into the repair shop to get a diagnosis. I'm at the edge of my technical skill with this issue and I really don't want to damage any hardware further.

 

[Phaaze88]

How long have they had this unit for?

If you do take it to a repair shop, don't expect too much - hell, they might even give you an incorrect diagnosis.
A lot of employees at PC repair shops don't seem to know what the heck they're talking about half the time.

Your PC works, but you just need to get this diode on the HDD replaced, and you can use it again.

 

[fzabkar]

Remove the shorted TVS diode, if that is your problem. My FAQ tells you what to do.

 

[Coanski]

Remove the shorted TVS diode, if that is your problem. My FAQ tells you what to do.

I'm not 100% sure that's my problem. Plus I'm not sure what's causing the short. So if I remove the shorted TVs diode then plug it back in, I may damage it further. Thanks much for replying. I will try a few more avenues over the next few days and post my findings

 

[Phaaze88]

I'm not 100% sure that's my problem. Plus I'm not sure what's causing the short. So if I remove the shorted TVs diode then plug it back in, I may damage it further. Thanks much for replying. I will try a few more avenues over the next few days and post my findings

If you reread the article on the TVS diode, it says that this part acts as overvoltage protection, and when this trips, it sacrifices itself to save your HDD.
The reason the PC doesn't boot up when the HDD is plugged in is a safety mechanism. As long as the old burnt out diode remains, you won't be able to use it.

 

[fzabkar]

Measure the power supply voltages at the SATA plug.