P4P800 and FireWire hookup

  • Thread starter Thread starter TxNative
  • Start date Start date
T

TxNative

I have a front panel with FireWire that I want to hook up to the internal MB
1394 connector. However, the MB connectors has more pins than the cable from
the front panel. While I am sure about most of the connections, there are a
couple that I am not. Hope someone can help.

Cable has: TPA+, TPA-, TPB+, TPB-, VP, VG, GND.

Motherboard has: TPAO+, TPAO-, TPBO+, TPBO-, GND, GND, GND, +12v, +12v.

I can figure out the Data lines and the GND connection.
My problem is with the VP and VG on the cable. Do those go to the +12v pins?
Or is the VG a GND connection?

Any help?
 
"TxNative" said:
I have a front panel with FireWire that I want to hook up to the internal MB
1394 connector. However, the MB connectors has more pins than the cable from
the front panel. While I am sure about most of the connections, there are a
couple that I am not. Hope someone can help.

Cable has: TPA+, TPA-, TPB+, TPB-, VP, VG, GND.

Motherboard has: TPAO+, TPAO-, TPBO+, TPBO-, GND, GND, GND, +12v, +12v.

I can figure out the Data lines and the GND connection.
My problem is with the VP and VG on the cable. Do those go to the +12v pins?
Or is the VG a GND connection?

Any help?
Click to expand...

VP is a positive voltage like +12V. VG is ground (GND).
The GND terminal on the cable is probably the cable shield.
So, you'll be connecting to two of the ground pins.

Be very careful with front panel wiring. My case had
the TPA+/- and TPB+/- pins reversed with one another, and while
that would not be fatal, if your case manufacturer makes any
mistakes with the VP/VG pair, you could damage an expensive
Firewire device. Find a picture of the Firewire connector on
the Internet and use an ohmmeter to verify the labelling
on the wires.

Also, since PC's don't implement proper galvanic isolation
between VG and ground, you should plug all your line powered
Firewire devices into the same power strip as your computer.
That will help ensure they are all at the same ground potential
(if one of them has the safety ground pin on the power cable).

Finally, there are some issues with hot plugging Firewire
devices and also with powering order of external Firewire disk
enclosures. On one Firewire enclosure I have, which is self
powered, if you turn off the power switch on the back of the
enclosure, the drive LED on the front of the enclosure remains
half-lit. This indicates the enclosure is still drawing power,
and that cannot be good for the bridge board.

HTH,
Paul
 
Thanks for the help. I had heard that some case manufactures had reversed
the +12v and Gnd. I plan on checking it completely.
Just wanted to be sure on the VG.
Thanks.
 
Back
Top