Andrew Davie wrote:
>
> I have just retreived a BBC computer.
> Seems to work fine, and I have managed to get directories of several of the
> (rather warped) 5.25 disks. I'm extremely surprised any data is readable at
> all - nice looking tandem dual floppy.
> However, onscreen I see there's a problem with the machine.
> I see perhaps 1/5th of the screen and then it repeats. Furthermore, the
> width of the screen isn't correct... that is, I see 20 or so character wide
> lines displaying and thus staircaising. I suspect its a hardware problem
> (almost 100% certain here, I've tried software mode changes - same in every
> mode), but have nil hardware expertise.
> So, when (occasionally) i see a > prompt, and type, i see what I type
> perhaps 20 times in varying places on the screen, each line offset from the
> other.
> Can anyone suggest my first steps to playing with it - what sort of chips
> should I be looking for, perhaps?
> I know, I'm behind the 8-ball, but you're all such brilliant guys at
> restoration, right?
> Any help much appreciated.
> Cheers
> Andrew
Hi Andrew:
Here is what I would look for and try to adjust --- Horizontal
frequency.
This sounds like it is some multiple of the desired (for the monitor)
rate. That's what's getting the multiple images across the width of the
screen.
Also (maybe first, but definitely in conjunction with the above) look
for 'Vertical' frequency/lock. This one is what is getting you multiple
images in the vertical direction. Memory says that the adjustment is
"roll down (image) and just return the adjustment the other direction
till it locks in place."
The 'horizontal lock' is a much courser adjustment.
(This is all standard TV/Monitor adjustment stuff. If anyone has any
specific advice different from this, by all means, give it a try.)
Chuck
--
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He, who will not reason, is a bigot; William Drumond,
he, who cannot, is a fool; Scottish writer
and he, who dares not, is a slave. (1585-1649)
While he that does, is a free man! Joseph P. 1955-
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(be sure to correct the return address when using 'reply')
Chuck Davis / Sutherlin Industries FAX # (804) 799-0940
1973 Reeves Mill Road E-Mail -- cad_at_gamewood.net
Sutherlin, Virginia 24594 Voice # (804) 799-5803
Received on Fri Feb 13 1998 - 23:22:44 GMT