Given the service manual arriving and a day away from the Beeb heap in the garage, I was absolutely champing at the bit to try and get the Domesday system working. After finding the focus error, the service manual suggested cleaning first (easy), or replacement of the focusing module (pretty much impossible). I’d got a few photography-grade cleaning buds in my lens bag so that seemed like the first port of call; goodness me, the muck that came off that lens, all that grease and dust – it’s a wonder the sodding thing hasn’t got more in it. Anyway, that cleaned, I powered it up with the debug codes on.
I’ll be honest with you, I wasn’t expecting it to work! Thus I was really pleasantly surprised when with a ‘rumble’ the disc span up. It seemed quite shaky on its bearings and spent 2-3 minutes ‘focusing’ and recalibrating itself, and eventually I shut it off again thinking it was still bust. Bring it up to read the POST codes some more and – well I’ll be damned, I was rewarded with the intro video from the Community Disc on the screen.
A quick bypass of the CUB monitor that the Beeb was showing, and this was the result. Hooray!
Power-down of the LV player to get rid of the POST codes, and it came back up no problems. No shaky disc, no problems reading, I spent the next ten minutes trying each side of both discs in turn which worked fine. It even showed the video on side 4, and searching worked fine. Now this is important, because in order for the computer to allow searching, almost everything needs to work – the SCSI card, the Master AIV, the 65C12 coprocessor inside the Master, the genlock (which is apparently one of the more frequent things to go pop) and the LV player itself.
All is not completely happy though – we still have no sound. There’s a very slight ‘fzz’ in the speaker when the audio is meant to get to a higher volume, and if you switch off either audio channel you get a satisfying ‘pop’ from the audio as it cuts in and out. This is leading me to believe it’s something as simple as a popped bit of the amplifier circuitry, which should be trivial to fix from the service manual.
If you’re curious, photos are here. There will be more (and some screenshots) once I’ve fixed the sound, and I’ll try and encode the video too.
January 13, 2008 at 5:27 pm
Very cool. I’m always impressed with your Beeb revival work, coaxing them back to life once more. The last I saw of a BBC Domesday system was photos in (B)AU.