Mac Pro 2007 No Power to Hard Drives

SMC RESET

Did you try swapping without shutting down? They are not hot-swap drive bays

Do you have a graphics card that only uses power from the PCle slot or one the also uses power from PCle connectors on the logic board?

Does the DVD drive work? I think that uses 12 volts. 3 1/2 inch HDs uses 12 volts as well as 5 volts while USB onlyuses 5 volts. Thus maybe the 12 volt output of the power supply is bad or the is a problem with only the 12 volts to the HD connectors. Or it could be problem with the 5 volts suppy to the HD.

Are yo using a 2 1/2 inch drive? in a sled? I ask since those only use 5 volts.

This

http://www.xlr8yourmac.com/systems/Mac_Pro/Bluetooth_MacPro_install/Bluetooth_Ma cPro_install.html

discusses

Note the connector for the antenna is located on the backside (right) possibly causing the lead to ground out on the logic board should it become loose. It will work but I was not comfortable with the fact the lead could short the logic board. A costly replacement.

That means that the power supply is OK but that there is a problem on the logic board prevent power from going to either the 5 or 12 volt connections.

Does your DVD drive use the molex power and PATA data connection?

It is relatively easy to measure power/voltage to a molex connector vice a SATA connection.

With power on, take your multi-meter and read the Voltages at any 4-pin Molex connector, in use or not. You can push the probe in either the front or the back of the connector to make contact with the wires.

You should find the measurement between the grounds and the colored wires producing a bit over 5 Volts on one, and a bit over 12 Volts on the other. If the 5 Volts is missing or bad, I expect nothing will run. If the 12 Volts is missing or bad, I expect you have a power problem (power supply or power cabling).

Disk drive connector (AMP MATE-N-LOK 1-480424-0 Power Connector)

AMP MATE-N-LOK 1-480424-0 Power connector (female pins)
Type	Electrical power connector
Production history
Manufacturer	AMP
Produced	1963
General specifications
Width	21 mm (female), 23 mm (male)
Height	6 mm (female), 8 mm (male)
Pins	4
Electrical
Signal	Yes
Max. voltage	12 V
Max. current	11 A/pin (30 °C rise)
Pin out
Male Pins (Female Connector)
Pin	Color	Type
Pin 1	Yellow	+12 V
Pin 2	Black	Ground
Pin 3	Black	Ground
Pin 4	Red	+5 V
18 AWG wire is typically used.

The desktop computer hard-drive connector is pictured here. It has 4 conductors, with the standard pinout as follows:

SOURCE:

images and text from wikipedia.org

.

SInce the OP is using the PCle 6-pin connector to power the graphics card that would indicate that the 12 power supply is OK would it not?

lllaass wrote:

SInce the OP is using the PCle 6-pin connector to power the graphics card that would indicate that the 12 power supply is OK would it not?

Yes. If that card is working properly under load, it is very likely that the 12 Volt supplies are fine.

An important classical debugging procedure has you:

1) remove EVERYTHING that could be dragging down power. Start with the motherboard and minimal RAM, looking to get the chime.

2) add the keyboard and mouse.

3) add the graphics card and look for blinking question mark.

4) add a SINGLE boot device. In this case, where EVERYTHING is suspect, try a Hard Drive with the add-on DVD drive disconnected ¿maybe that adapter died?

5) continue building your Mac back a part at a time.

I've just had the same thing happen, did you ever figure out a solution Ryan?