[MacDV] Re: DV - FW pinouts

[Peter Tattersall]

On Saturday, May 24, 2003, at 11:26  AM, Frank Farwell wrote:

> Peter
> Ok this is what going on now that ive tried many things.
>
> my Sony TRV-103 camcorder has worked fine with iMovie for that past 3 
> years now it is not recognized. So i tried it on my powerbook iMovie 
> doesn't recognize on it either. So i presume the FW port is bad on the 
> camcorder (i tried another camcorder and it worked fine). But then i 
> put the camcorder on a phillips DVD recorder w/ FW port it works fine. 
> Now then i installed iMovie on an iMac with OS9 (OSX on the others) 
> iMovie recognizes and works with the camcorder fine. So now im lost. 
> Ive deleted preferences, run repair permissions, ran disk warrior. 
> iMovie still doesnt recognize the camcorder. But it worked fine just 2 
> days ago. Im lost.
>
> technology can sure be a pain when it doesnt work right.
>
> frank

Despite the way it may have sounded, I'm not a hardware person - I 
write software for a living. However, I can come up with a hardware 
scenario which would result in the behaviour you describe. The thing 
with the firewire design as I understand it is that the data is sent on 
one line and the other line acts as a clock to validate the signal for 
high speed transfers. I would expect that if the control electronics 
are just slightly out of spec on each end that you could wind up with 
two units which don't recognise each other but do recognise other units 
- the situation you describe. As the hardware ages the tolerances may 
drift slightly so that the units were just inside each other's range 
may have drifted out. Probably the only way to confirm that would be to 
put a scope on the signal lines and check the timing and voltages.

You have presumably tried such things as shutting the system down for 
an hour or so before restarting so as to check for thermal effects? 
Reviewed any recent software installs? I seem to recall that there were 
problems reported a while back where upgrading the system resulted in 
loss of firewire connectivity, but a Google search didn't turn up 
anything (but that could be a problem with getting the right search 
terms). If you've tried the obvious things, you're out past my 
experience (jiggling the connections and mumbling under your breath 
sometimes works, but it's not reliable).