Sign in with
Sign up | Sign in
Your question

reversed polarity on harddrive!

Last response: in Storage
Share
June 6, 2008 3:58:09 PM

I have this stupid light controller in my computer which the pins become lose and so i had my harddrive plugged into my light controller which was plugged into my power supply. How ever i was cleaning my computer up and the pins came out of the molex connector. Well i switched the yellow with the red :pt1cable:  . Tried to spin up the harddrive. No spin! but while i had the polarity reversed my lights went half on. Guys what should i do? cannot find a replacement for the circuit board as its an old 60gb spinpoint.

thanks
a c 342 G Storage
June 6, 2008 4:06:36 PM

You don't say whether you tried the easy / obvious solution. Did you fix the mixed-up leads and then re-connect properly to try? Sometimes you're lucky and it works anyway because even the wrong connections did no permanent damage. Sometimes you're not so lucky.
a c 353 G Storage
June 6, 2008 5:07:33 PM

Of Little use; But, you did not apply a revearse polarity. What you did was apply a +12V to where the +5 V is normally applied resulting in a very high overvoltage. Revearse polarity is easily protected by input diodes which would limit Current and prevent damage. However overvoltage is harder to protect against, Normally a Zener Diode in parallel that would Zener at a specified level and blow a replaceable fuse. As state - Of little use as end result is the SAME.

Since you tried it and it didn't work my instinct tells me you have Blown some of the 5 Volt circuit components. You might be able to find a new, or used HDD and swap circuit boards - It depends on if you have recently backed up your Data, If you have just bite the bullet and buy a new HDD and reload.
Related resources
June 6, 2008 6:25:30 PM

damn. yea i didnt think i reversed the polarity either. But i didnt think it was worse haha. Yes i really need to get stuff off this drive as i have all my music on it! :cry:  I cannot how ever replace any old harddrive circuit board with it tho right? thats the impression i was under over some googling. So i dont want to spend 500 dollars and have it professionally recovered. Is there a trick of the trade?

ps. I did try and reconnect it correctly multiple times.
June 6, 2008 6:26:27 PM

did not see any smoke either if that helps and yes i did need this experience to happen so i had a reason to go sata and buy a 500gb! woo
a c 353 G Storage
June 6, 2008 7:22:35 PM

Afraid your music is in that great digital beyond as the repair is most likely above our pay grades Sorry as I don't think there is a simple repair. If you are handy with a mutimeter and a soldering iron you could TRY to find the bad part by tracing the line from the +5 V pin.

Just thought of a simple protection method.
They could place a diode acrose the +5 and +12 V pins and a fusible link in the +5 or +12 V lines. The fusible link could be as simple as a very narrow trace. I mention this as they should anticipate a "Gorillia" pluging the molex in backwards. Use a magnifing clace and examine the traces, or ohms check them _ You Have NOTHING to loose. You could play with this after installing Your new HDD
June 7, 2008 2:43:02 AM

haha i wish my harddrive had you "simple" protection method. Ok so i unscrewed the pcb an i flipped it over to look at the circuits. help me out here whatdo i do next. i wish i wasnt a noob with harddrive pcb lol
a c 353 G Storage
June 7, 2008 3:29:17 PM

I assume you have a fair to good understanding of electronics and Have a multimeter. Bear in mind finding the problem is on the low probability side and repair might even be lower. Hope you have the so called "luck of the Irish"

1st - I do not have a "bad" hard drive (Should have kept one). I have a Maxtor that I am looking at without removing the PCB.
Note: allot of the components are surface mount components and it is impossible to to tell the differnce between a cap and a resistor much less determine a resistive value.

I plugged in a Molex pigtail (Has two females, one male). This is so I can insert one lead of the multimeter and use the other lead to check various points.

(1) Measure the +12 (Yellow) and the +5 (red) to ground (black) Then Measure the +12 to the +5V. . You should have a very high resitance reading. Mine: +5 to Ground 12 kohms, +12 V was 12 Megohms. Note on +12V the reading started at 5 Megs and slowly climbed to > 35 megohms. (Charging a cap). Next verify by reversing your multimeter leads. You may get an initial reading that is negative ohms. BUT it should drop to zero then climb to a high positive value. (this is due to a charge on a cap that is discharging and then charging – Normal.
(2) Now you can start tracing.- My drive has what appears to be a surface mount resistor off of each Molex pin. I then measured each Molex pin to both sides of the component. HOWEVER they have a Very low resistance (less than 0.1 ohms. So could be acting as a fuse??). IF one of these checks open, THEN measure the side opposite the Molex connector two ground. If you have a low resistans, you have a component that may have shorted out causing current to blow the resitor/fusistor. See second installment.

This is a start - Have Fun.

If you get an open: (1) your meter may show an open above 20 Mohms - Mine goes to 40 Megs or (2) the resitor/fusesistor may be open:
Also; if the resistor/fusesistor is open. It indicates excess current and is probably a result of anoter component. I have a feeling that they are there to protect the PSU or prevent excess current causing further damage and NOT the HDD.
a c 353 G Storage
June 7, 2008 4:05:31 PM

2nd installment.
Depending on how far you want to take this, and $$$.

You can use two little power packs, one 5V and one 12V. Get two female connectors from radio shack (maybe two bucks apiece) wire them to a spare molex connector. Plug this in and you can now also make voltage checks.

This would also be advisable if say you find one of the input resistors/fusesistors open. You could solder a single strand of wire across the open (use a Low wattage soldering pencil with a FINE tip) and test with this "Jury rig" for excess current.
June 8, 2008 2:31:22 AM

Thanks a lot man i defiantly will try and repair this board. And to valis. Unfortunately that's the 2.5 inch version i have the 3.5 :cry: 

Oh and i am going to die before i stop trying to get this dang hard drive to work again haha.

What do you think my last resort is before shelling out 500 bucks for professionals?
June 8, 2008 2:47:10 AM

yesssssssssssssssssssssssssss i founddddddddddddddddd it!!!!!!!!!!!!! Because i dont have a multimeter and i cannot find anyone i know that has it iam gonna buy that drive on ebay. crossing my fingers for the same firmware.
a c 353 G Storage
June 11, 2008 6:06:46 PM

OP - That is your best option, wishing you "the best of british" Luck
a b G Storage
June 13, 2008 8:46:22 PM

Good luck on the firmware.
!