Date   : Tue, 28 Sep 2004 18:29:17 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Electron Sync problem

> Whenever I connect the machine to my monitor, which works fine on my Beeb,
> The display rolls - There's nothing I can do on the monitor that will make
> it stop.

Same cable or different? Sounds like total loss of sync, which could be
cable (not if you've ruled it out on your beeb obviously), connector
(not making contact, or broken joint on the PCB), or further back in the
video chain. I'd rule out the former two first!

Do you have a monitor with a phono input? If so, hook the Electron up
with that from the video out and see if it works. If it does, then it
would suggest a problem with IC14 (74LS86) or PCB track / solder joint /
RGB cable.

The only thing upstream of IC14 on the sync line is IC19 (74LS08) which
might have failed and would knock out sync to all video outputs. Further
back from that it's the main custom chip, in which case it's Game
Over...

Check LK3 has a jumper on it too; of it was left without one it could
mess things up.

cheers,

Jules