Date : Sat, 27 Sep 2008 14:54:48 +0100
From : jumbos.bazzar@... (Mark Haysman)
Subject: Domesday video problems
Hi.
I'm not familiar with that particular player, but it's not been set to NTSC
has it? (If it has an NTSC option?). Looks like there's a problem in the
video output for sure as you say you've tried it on different monitors, but
difficult to say unless you can put the output on a scope or waveform
monitor to see what it looks like.
I presume the Beeb loads a program from the LV rom that corresponds to the
images on the disc? If that's loading okay, it's unlikely to need a belt,
and the optics are more than likely okay. It may well be a cap in the
encoder circuit to the video output that you suggest.
Mark.
----- Original Message -----
From: "Adam Sampson" <ats@...>
To: <bbc-micro@...>
Sent: Saturday, September 27, 2008 2:36 PM
Subject: [BBC-Micro] Domesday video problems
> Hi all,
>
> I'm currently trying to resurrect a Domesday system:
> http://offog.org/stuff/domesday/25092008119.jpg
>
> This belongs to the Computing Lab at the University of Kent, where I
> work. The Laserdisc player had been sitting in our networks lab for at
> least the last ten years, and one of our sysadmins found the rest of it
> during some recent room moves.
>
> I've got: a Master AIV, a Laserdisc player and remote control, a
> trackball, a Viglen dual disc drive, the Domesday, Volcanoes and Ecodisc
> discs, the Master, Master AIV and Domesday manuals, keystrips for
> View/ViewSheet and the Domesday system, and some sundry cables. I'm
> missing the monitor, video cables, and the manual for the Laserdisc
> player -- fortunately, I had an A310 monitor in storage which seems to
> work.
>
> It's the cleanest BBC setup I've ever seen -- I'm used to having to
> clean sticky crud off cases from machines that have been used in
> schools, but this just needed some dust wiping off! The Laserdiscs are
> also in good condition: no visible rot, and the only damage is a dent in
> (fortunately) the blank side of the Volcanoes disc. Here's the output of
> *HELP showing the ROM versions present in the Master:
> http://offog.org/stuff/domesday/25092008112.jpg
>
> So far, I've rebuilt the 1980s-vintage battery pack in the Master and
> reset the CMOS settings to those in the AIV manual, set the SCSI ID on
> the Laserdisc player back to 0, and made up a replacement RGB cable to
> go from the Master to the player (with all six pins connected straight
> through).
>
> The system now mostly works: it'll boot off a Laserdisc, and you can
> navigate around happily. However, as you can see in the pictures,
> there's something wrong with the video output: the overlay graphics from
> the BBC are fine, but the genlocked video from the Laserdisc doesn't
> appear correctly:
> http://offog.org/stuff/domesday/25092008116.jpg
> http://offog.org/stuff/domesday/25092008118.jpg
>
> I've tried a different monitor with the same result. I've also tried
> playing a normal Laserdisc without the BBC attached, and got a similar
> effect:
> http://offog.org/stuff/domesday/25092008107.jpg
>
> I believe the Laserdisc player was used as a video source for other
> experiments in the early 90s -- the SCSI ID was set differently, two of
> the Laserdiscs are marked "stills" and "video", and I've found
> framegrabs from them on other old machines. It's therefore plausible
> that someone might have fiddled with other settings on the player -- or,
> since it's been sitting around for at least ten years unused, that a
> capacitor or belt needs replacing...
>
> Since I don't have the Philips manual, I'm at a bit of a loss as to what
> to try next. Has anyone seen this problem before? How do you put the
> player into diagnostics mode? Is the service manual still available?
>
> The full set of pictures is here:
> http://offog.org/stuff/domesday/g/
>
> Thanks very much,
>
> --
> Adam Sampson <ats@...> <http://offog.org/>
>
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