duplicated post please delete admin!

[Simon Spiers]

Hi all, wonder if you can help>
I have just moved my 8568a  from one side of the workshop to the other and now it has a problem.
When the unit has been on for a while the CRT starts to show scrambled characters and the graticule seems to vanish.
I have been over both units cleaning edge connectors and checking ESR of the tant caps but still no joy,
It also shows the check instrument 1 led one this fault starts. Which is instrument 1?
The actual waveform displayed looks un corrupted, so I am guessing the fault must lie in the display units character generation section?
Any ideas please.
Simon

[Simon Spiers]

The problen that seemed to vanish with the covers off is now back again once i put the instrument together 
Another odd thing i descovered is than when recall 8 or 9 is rrequested you even loose the waveform info. 
This suggests a rom corruption an only recall 8 or 9  have this effect.
Looking for spares if anyone can help.