Help identify this part

Tool suggestions, soldering tips, general useful electronics knowhow.
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Acsi
Posts: 52
Joined: Tue Nov 07, 2017 7:52 am

Help identify this part

Post by Acsi »

Need some help identifying L3 on this board as I suspect it’s the problem on my SATA backplane.

It’s the only thing showing any sign of damage and I’m only saying that because it should look the same as L2 and L4 (L1 is not in the photo but is the same as 2 and 4)
DCAC8FB8-C814-4A8D-9913-4F2DACCA06CA.jpeg
DCAC8FB8-C814-4A8D-9913-4F2DACCA06CA.jpeg (462.95 KiB) Viewed 2288 times
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exxos
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Re: Help identify this part

Post by exxos »

Can't really tell from the image but doesn't look broken ?
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Maximilian
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Re: Help identify this part

Post by Maximilian »

HP SATA backplane?, one channel not working?, or a short?

Well, its a coil, it should measure the same as the rest of the coils, probably a very low resistance/short.
These should almost never break, only if there is a short on the component that the coil feeds.

IMHO It looks like the board was repaired and the coil, U6 and U7 were swapped, there also seems to be a bit of flux resedue around the 8 pin chip.
Acsi
Posts: 52
Joined: Tue Nov 07, 2017 7:52 am

Re: Help identify this part

Post by Acsi »

Thanks. Its in a Akitio Quad X enclosure. The drive in bay 3 will not spin up (tests fine in bay 4). Unit was secondhand when I purchased it

I'm going to pull it apart today and do some measurements. It's not easy to get to that side of the back plane. I believe that bay has lost it's 5v feed but need to verify.

OK so it's got no voltage at the drive bay connector so I believe the issue may actually be that it's not sensing there is a drive connected. Seems to need to be also connected to the computer before it will put any power onto the SATA connectors.

Looks like I'll just be running this as a 3 bay unit :(
Maximilian
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Re: Help identify this part

Post by Maximilian »

Are the other bays also without power?
Normally the power is always applied and the firmare takes care of the spinup.
Do you have the numbers from the chips?, cant make them out on the picture.

From WIKI:
In computers with multiple hard drives, a method called staggered spin-up can be employed to prevent the excessive power-consumption of spin-up, which may result in a power shortage. Power consumption during spin-up is often the highest power draw of all of the different operating states of a hard disk drive. Staggered spin-up typically starts one drive at a time, either waiting for the drive to signal it is ready or allowing a predefined period of time to pass before starting the next drive. If the power supply is able to supply sufficient current to start multiple drives at a time, that, too, is common.

Staggered Spin-up (SSU) and Power-Up In Standby (PUIS) are different features that can help control spin-up of multiple drives within a computer system or a disk subsystem. Both are defined in the ATA Specifications Standards. See Serial ATA for more information.

One feature, called Power-up in standby (PUIS) (also called PM2[1]) is used on some Serial ATA (SATA) and Parallel ATA (sometimes called PATA or IDE) hard disk drives. PUIS requires BIOS and/or driver support to use. When power is applied to the hard disk drive, the drive will not spin-up until a PUIS Spin-Up command is issued. The computer system BIOS or RAID controller must issue the command to tell the drive(s) to spin-up before they can be accessed. PUIS can be enabled by tools such as hdparm for drives which support this feature.

Another feature, called Staggered Spin-up (SSU) is used on most Serial ATA (SATA) hard disk drives. This is more common than Power-Up In Standby (PUIS) because it does not require any special commands to get the drive to spin-up. The drive electronics waits for the SATA Data Phy (Physical I/F) to activate to spin-up the drive. The computer system BIOS and/or RAID controller or RAID driver set can delay and control when the different drives will spin-up.

With Western Digital hard disk drives, Pin 11 of the SATA Power Interface controls whether Staggered Spin-Up (SSU) is enabled or not. Pin 11 is also used as an activity LED connection. When the drive is initially powered on, the drive senses whether Pin 11 is left floating (high or '1' logic state) or grounded (low or '0' logic state). SSU is disabled when Pin 11 is grounded. When disabled, the drive will spin-up as soon as power is applied to it. SSU is enabled when Pin 11 is left floating or driven high (high or '1' logic state). The drive will not spin-up until the SATA Phy Interface becomes active with a connection to a SATA controller or SATA RAID controller. The SATA or SATA RAID controller can control when and how many drives can be spun-up. SSU and PUIS are features that are configured in software or firmware by the manufacturer.

Information from the Fujitsu Serial ATA Interface for Mobile Hard Disk Drives whitepaper:[2]

Staggered spin-up is a simple mechanism by which the storage subsystem controller can sequence hard disk drive initialization and spin-up. Having this feature not only provides greater reliability, but it allows the system to avoid power surges if all of the HDDs spin up simultaneously during system power up (in a multi-drive environment). Another benefit to having staggered spin-up is the use of more cost-effective power supplies, which prevents power supply damage and system brownouts.

Note that staggered spin-up of disks is a feature of many multi-drive systems using SATA and RAID. It is not typically used on mobile platforms.
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