Osborne OCC1 problem

Roy J. Tellason rtellason at verizon.net
Fri May 16 20:00:38 CDT 2008

On Friday 16 May 2008 15:31, Tony Duell wrote:
> > > That's why I'd start by looking at the horizotnal sync pulses
> > > when you have the lines and when you have a good display
> > > (even if the machine has crashed). If they're the same
> > > timing, then the fault is monotor (or PSU?) releated. If not,
> > > then the video timing circuitry is palying up _or being
> > > mis-configured by software_
> >
> > H-sync pulses (and the vsync, for what it's worth) are identical when the
> > machine is crashed or running. However, I don't understand why that would
> > put the fault in the monitor? And it still doesn't explain the digital
> > artifacts...
> Well, if the Hsync pulses are indential whether the display is stable or
> not, then the Hsync generation circuitry is not the prolem. And if the
> monitor is not locking to them, the fault is either the monitor or the
> PSU, presumably.

Without any indication of amplitude or repetition rate it's hard to say 
whether they're good Hsync pulses or not.  The image of that Vsync pulse sure 
looks a little odd to me...

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