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Deze versie is geschreven door: Keri Rautenkranz ,

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Using the external cable is unlikely to work correctly on a non- iMac specific drive, and it even has to be for the correct series iMac.
 
The generic drives usually do not have the correct firmware to use Apple's temp cable.
 
In the case of WD drives, the late 2009 iMac repurposes pin #5 on the jumper block for temp data.
In the case of WD drives, the late 2009 iMac repurposes pin #5 on the jumper block for temp data.
 
On a generic WD drive, pin #5 floats at about 2.5 v. If it is shorted to pin #6, (ground, 0 v) the drive is set for SATA 150 mode.
 
On a WD Blue drive pulled from a late 2009 iMac, pin #5 floats at 2.5v, and carries a 2-pulse signal every 4 seconds. Presumably, this either carries the temperature data, or is some kind of handshake.
On a WD Blue drive pulled from a late 2009 iMac, pin #5 floats at 2.5v, and carries a 2-pulse signal every 4 seconds. Presumably, this either carries the temperature data, or is some kind of handshake.
 
An Apple-branded WD drive pulled from a 2007 iMac lacks this signal, as do the new generic WD drives I tested.
 
Apple's 2-wire cable connects pins #5 (signal) and #6 (ground) to the logic board. If the cable is jumpered, the logic board goes to low fan. If open, or if the correct signal is not present, it goes to high fan.
 
So, if you attach the WD temp cable upside down, as suggested elsewhere, you disable fan control and set the drive for SATA 150 mode!
 
Fortunately, OWC offers an external temperature sensor that mimics the correct signals from the iMac-specific drive. This allows use of non-Apple drives, including SSDs in the main drive bay.
 
It's possible that an Apple optical drive temp sensor, which is taped in place, could work, as they do have the same logic board connector. It does not appear to be a simple thermistor. I have not checked the function of this. Perhaps someone could hook a scope up to one in a working system and see. The part number for a 2009 iMac optical drive temp sensor is: 593-1152
 
Why would Apple do such a thing? It's better, and cheaper too, from their point of view. The drive's internal sensor is more accurate than the older taped-on sensor, and not using the data stream to read temp data prevents slowing down the system. Serviceability and upgradeability with non-Apple parts has never been a top priority for Apple, as the machines are meant to be repaired by Apple and replaced when obsolete.

Status:

open

Bewerkt door: Keri Rautenkranz ,

Tekst:

Using the external cable is unlikely to work correctly on a non- iMac specific drive, and it even has to be for the correct series iMac.
 
The generic drives usually do not have the correct firmware to use Apple's temp cable.
 
In the case of WD drives, the 2009 iMac repurposes pin #5 on the jumper block for temp data.
 
On a generic WD drive, pin #5 floats at about 2.5 v. If it is shorted to pin #6, (ground, 0 v) the drive is set for SATA 150 mode.
 
On a WD Blue drive pulled from a 2009 iMac, pin #5 floats at 2.5v, and carries a 2-pulse signal every 4 seconds. Presumably, this either carries the temperature data, or is some kind of handshake.
 
An Apple-branded WD drive pulled from a 2007 iMac lacks this signal, as do the new generic WD drives I tested.
 
Apple's 2-wire cable connects pins #5 (signal) and #6 (ground) to the logic board. If the cable is jumpered, the logic board goes to low fan. If open, or if the correct signal is not present, it goes to high fan.
 
So, if you attach the WD temp cable upside down, as suggested elsewhere, you disable fan control and set the drive for SATA 150 mode!
 
Fortunately, OWC offers an external temperature sensor that mimics the correct signals from the iMac-specific drive. This allows use of non-Apple drives, including SSDs in the main drive bay.
 
It's possible that an Apple optical drive temp sensor, which is taped in place, could work, as they do have the same logic board connector. IIt does not appear to be a simple thermistor. I have not checked the function of this. Perhaps someone could hook a scope up to one in a working system and see. The part number for a 2009 iMac optical drive temp sensor is: 593-1152
It's possible that an Apple optical drive temp sensor, which is taped in place, could work, as they do have the same logic board connector. IIt does not appear to be a simple thermistor. I have not checked the function of this. Perhaps someone could hook a scope up to one in a working system and see. The part number for a 2009 iMac optical drive temp sensor is: 593-1152
 
Why would Apple do such a thing? It's better, and cheaper too, from their point of view. The drive's internal sensor is more accurate than the older taped-on sensor, and not using the data stream to read temp data prevents slowing down the system. Serviceability and upgradeability with non-Apple parts has never been a top priority for Apple, as the machines are meant to be repaired by Apple and replaced when obsolete.

Status:

open

Origineel bericht door: Keri Rautenkranz ,

Tekst:

Using the external cable is unlikely to work correctly on a non- iMac specific drive, and it even has to be for the correct series iMac.

The generic drives usually do not have the correct firmware to use Apple's temp cable.

In the case of WD drives, the 2009 iMac repurposes pin #5 on the jumper block for temp data.

On a generic WD drive, pin #5 floats at about 2.5 v.  If it is shorted to pin #6, (ground, 0 v) the drive is set for SATA 150 mode.

On a WD Blue drive pulled from a 2009 iMac, pin #5 floats at 2.5v, and carries a 2-pulse signal every 4 seconds. Presumably, this either carries the temperature data, or is some kind of handshake.

An Apple-branded WD drive pulled from a 2007 iMac lacks this signal, as do the new generic WD drives I tested.

Apple's 2-wire cable connects pins #5 (signal) and #6 (ground) to the logic board.  If the cable is jumpered, the logic board goes to low fan. If open, or if the correct signal is not present, it goes to high fan.

So, if you attach the WD temp cable upside down, as suggested elsewhere, you disable fan control and set the drive for SATA 150 mode!

Fortunately, OWC offers an external temperature sensor that mimics the correct signals from the iMac-specific drive. This allows use of non-Apple drives, including SSDs in the main drive bay.

It's possible that an Apple optical drive temp sensor, which is taped in place, could work, as they do have the same logic board connector. I have not checked the function of this. The part number for a 2009 iMac optical drive temp sensor is:  593-1152

Why would Apple do such a thing? It's better, and cheaper too, from their point of view.  The drive's internal sensor is more accurate than the older taped-on sensor, and not using the data stream to read temp data prevents slowing down the system. Serviceability and upgradeability with non-Apple parts has never been a top priority for Apple, as the machines are meant to be repaired by Apple and replaced when obsolete.

Status:

open