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Wondering why drive only spins up when head connection on PCB is blocked

J

jttraverse

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This is about trying to access data on a Seagate Constellation (ST33000651NS). I've been doing some testing, part of which involves blocking the Head Rack Assembly connectors under the PCB with a thin plastic or paper sheet. What I've noticed is that when the HRA connections are blocked and the drive is powered on then the platters spin up as expected (no clicks or odd noises). But when the HRA connection is -not- blocked, the heads do not spin up and it seems there's no life in the drive.

Is it normal that the HRA connection being enabled should stop power to spin the platters? Or does it indicate there's a problem possibly with the PCB, or something else?
Thanks,

JT
 
My first thought is that the HRA is defective so the drive does not spin up with it connected. Logic would dictate that the same should happen when you disconnect the HRA though.

But I am still leaning towards a failed errorcheck, with the HRA connected, that prevents the drive from spinning up.
 
jttraverse said:
This is about trying to access data on a Seagate Constellation (ST33000651NS). I've been doing some testing, part of which involves blocking the Head Rack Assembly connectors under the PCB with a thin plastic or paper sheet. What I've noticed is that when the HRA connections are blocked and the drive is powered on then the platters spin up as expected (no clicks or odd noises). But when the HRA connection is -not- blocked, the heads do not spin up and it seems there's no life in the drive.

Is it normal that the HRA connection being enabled should stop power to spin the platters? Or does it indicate there's a problem possibly with the PCB, or something else?
Thanks,

JT
Click to expand...
I have encountered this problem with a WD drive. Block the 3.3v line on the power connector and the drive will spin up as expected.
 
Hi Calenhad,
Thanks for the reply. The HRA is something to think about since I had to replace that as well. Even so, the replacement came from a donor drive that matched in every possible way (Model, PN, FW, SN, etc.) and changing it went about as smoothly as I think it could have and, again, no odd sounds, clicks, etc. But I know that doesn't guarantee anything at this point. I do agree with you that, logically, if a defective HRA was stopping the spin-up then disconnecting it completely shouldn't make it work better, so to speak.

Now, if I can figure out how to do an errorcheck, that might help.
Thanks again...

The PWDIS question was new to me, though after looking into it I can understand why it could be a consideration. That said, I was told by Seagate that this drive was built circa 2012, which I think was a few years before the PWDIS standard came about (if it's a standard now). So I'm not sure what to think, but I'll keep looking into it.
 
80251 said:
Lex, does the spec sheet for your WD drive indicate it supports PWDIS?
Click to expand...
No idea. All I know is that taken out of it's external enclosure and plugging into a PC directly, it fails to spin up or show up in device manager. When I use a Molex to SATA power adapter(which has no 3.3v connection), the drive spins right up and operates as one would expect. This is exactly the problem the OP is having. Regardless of the protocol being used, the 3.3v connection is the solution. Block/remove the 3.3v connection and the drive will operate as expected.
Here's the adapter I used;
www.ebay.com

2X IDE/Molex 4-Pin Male To Serial ATA SATA 15-Pin Female Power Adapter Cable | eBay

Convert one of your extra 4-pin Molex power connectors into a SATA power connector. - Good for all SATA harddisk 2.5 and 3.5. - Compatible SATA CD Drives. - 2X Cables. - Cable Length(approx.). : 15cm Cable length.
www.ebay.com
 
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What's hilarious is that I have the exact OPPOSITE issue with my Samsung 870 QVO 4 TiB SSD. It won't work with a molex-to-SATA adapter (all the rest of my Samsung SATA SSD's do).
 
80251 said:
What's hilarious is that I have the exact OPPOSITE issue with my Samsung 870 QVO 4 TiB SSD. It won't work with a molex-to-SATA adapter (all the rest of my Samsung SATA SSD's do).
Click to expand...
Native SATA power contain 3.3V in addition to the 5V and 12V that MOLEX provides, which is a limitation when using adapters. So that probably means that drive uses 3.3V.
 
@Calenhad
The Samsung 870QVO spec. sheet says that it only uses +5V power. As a matter of fact I don't think there are any SSD's or HDD's that use +3.3V outside of PWDIS.
 
I'm glad this topic is getting views and replies that are all helpful. Even so, I'd still appreciate any ideas on my original post. Also, could there be variations in 'matching' PCBs? By that I mean even if my current 'donor' PCB appeared to match all the criteria, maybe they aren't all the same? Anything else?
 
80251 said:
The Samsung 870QVO spec. sheet says that it only uses +5V power. As a matter of fact I don't think there are any SSD's or HDD's that use +3.3V outside of PWDIS.
Click to expand...
It did sound weird when I wrote it. Never seen a drive use 3.3V before.
I had a better look at PWDIS and if your molex adapter does funny things with pin 3, then that could cause your problem. If the drive supports PWDIS it will shut down if pin 3 is at ~3.3V. Older SATA spec have 3.3V on pins 1-3, new spec have 3.3V on pin 1-2 and PWDIS on pin 3. Quick check with a multimeter can confirm if your adapter supplies voltage on pin 3 or not.
 
@Calenhad, my PSU predates the PWDIS std. so I'm assuming it supplies +3.3V to pins 1 to 3 of the SATA power connectors, because that's the SATA power standard previous to SATA 3.3 (or 3.2?). The weird thing is if the Samsung 870QVO supports the PWDIS std. it should be powered down when used with a pre-SATA 3.3 power connector. All my other SATA Samsung SSD's (all are older 850 Pros) work with the molex-to-SATA adapter, the 870QVO is the only one that doesn't. Along with the troubling incidence of 870EVO failures it's just another Samsung mystery that will never be solved.
 
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