Part 1:

my first question is all the 4 wire power connectors (intended for hardisks/dvd drives not mother board) are same. Right? I've been using all of them same and I had no problem for years.

Yesterday I borrowed a SATA disk from my friend and connected it my computer using Sata Power adaptor (4 wire)

enter image description here

and when I switched on the computer. There were fumes coming out of the connector. I immediately turned it off (in just one second).

I tested the voltages in the 4 wire power connector of my SMPS: enter image description here

They were 5.3v & 12.2V. I couldn't measure the current. But my SMPTS label reads:

DC Output:
3.3v (25A)
+5v (32A)
-5v (0.3A)
+12V (17A)
-12V (0.8A) 

And the SATA hard disk label reads

+5v (0.72A)
+12V (0.52A)

I'm shocked! I never noticed this. Does the "sata power adaptor" scale down the current to required? If it doesn't, I've been connecting same way for years. I never had any problem. This is the first time I'm encountering it.

Part 2:

I wanted to return the drive to my friend. He has two hard disks, SATA & PATA. Its the SATA that I borrowed. When he usually switches on. The CPU fan starts & then stops for a sec and starts again and continues working. That was the earlier situation. I don't know why it stops & starts?

Well, Now when I connect this SATA disk and switch ON the computer. CPU fan starts (just for an instant, not even a 0.5 sec) and stops. It doesn't start again, I mean the power from SMPS has stopped. But if I disconnect this SATA disk. It works fine.

What seems to be the problem? I've no idea about why there were fumes or why his SMPS starts & stops giving power? What is its relation with the SATA disk connection?

  • The power supply has blown. Replace it. There would be no molex connectors if they were not compatible with SATA / 4-pin power. – user3463 Feb 13 '11 at 5:49
  • @Randolph Potter: 1. Are you talking about my power supply (The one that has generated smoke)? 2. Whats up with the part2, I mean why isn't it working there? – claws Feb 13 '11 at 6:31
  • Wow, I haven't heard anybody younger than about the age of 65 say 'SMPS' since the early 90s. – Shinrai Feb 16 '11 at 23:17
  • @Shinrai: Why? Am I saying it wrong? Years ago I've been told that its called SMPS. What is it called now a days, btw? – claws Feb 17 '11 at 6:27
  • Nah, you're right. The term has just fallen out of use because there is no other kind of power supply in common use anymore - they're ALL SMPS. So generally people just call them 'power supplies' or 'PS' (note that the tag is 'power-supply'). I just thought it was interesting. :) – Shinrai Feb 17 '11 at 16:54

Sounds like you did some damage to your power supply, the SATA drive may have been mishandled when you were moving it or the MOLEX to SATA power adapter may have been faulty. Both issues sounds like a dead short in either the molex or drive. If the drive was mishandled or picked up moisture under it's circuit board in transit this could cause a dead short, the same would be true if any of the powered pins in the sata end of the adapter grounded out.

Either way the drive is more than likely shot and the adapter is suspect. I would toss the adapter and either scrap the drive or fire it off to a data recovery company if he has crucial files on it.

If you need help locating a good company in your area let me know and I can recommend one for you.


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