1394A external device can't be recognized

techo

hi All,
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is there any one had experienced 1394A external device can't be recognized under OS?
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I encounter this kind of issue recently.

OS is Vista & XP.

" v% c0 V/ _- p; P& p/ G1394A controller is Ricoh.
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the situation is I could see the removable icon shown on the system tray but there is no device in OS device manager.
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+ a: C8 S8 }8 mindeed there are some differents but I don't know why.
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  a) F8 X: u& AI wonder it's caused by BIOS but how to prove it?
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is there any spec or document could let me refer to?
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Thanks anyway!