Re: [CAD_CAM_EDM_DRO] monitor problems

Sounds like something has failed in the monitor which keeps it from
working at the lower scan rates used for text mode. Years ago some
of us used to run fixed-frequency workstation monitors on PC's which
would only work in high-res graphics mode. Had to find a small spare
to plug in if some sort of error message kept the machine from booting.

Today most monitors work at a wide range of sync frequencies... but
if something goes wrong they may not. The sound you refer to almost
sounds like arcing in the high voltage supply. Modern TV's and
monitors are remarkably optomized - the high voltage is dervied from
the inductive kickback of the horizontal deflection coil, via a high
ratio 'flyback' transformer. As such, the high voltage supply is
somewhat dependent on the scanning frequency (which depends on display
resolution amongst other things).

If you know the appropriate precations to work inside a TV/Monitor you
can try to look for obvious problems, but opening the case at all is
not a good idea unless you have some idea of how to work on the thing
safely - the picture tube is a capacitor which can be charged to
lethal votlage even when it has been powered off for some time.

Or you could just run it as a graphics only monitor with another for
text mode. Assuming that the problem isn't the shutdown circuit which
is supposed to make the set "unwatcheable" if the high voltage supply
wanders into the range where X-rays are generated.

Really the best bet is to replace it.

Chris

> Today I decided to hook up my "shop computor" and save the laptop which
> has been running my CNC lathe for other purposes. I loaded CNCPro and
> went to run it only to discover that the Dell/Sony trinitron monitor
> won't function in MSDOS mode. In fact it only displays when the Windows
> 98 blue screen appears as Windows does its final loading. No windows
> logo or anything other than a clicking that sounds like a gieger(sp?)
> counter. Then blink-a fully functioning Windows. I plugged in an old
> (out of focus) monitor to see if it was the computor but it funtioned
> without problem in DOS mode . Plugged the Dell monitor back in and
> nothing but clicking and a black screen. I checked the Windows settings
> to make sure that the correct monitor was specified and that it had the
> latest drivers. What am I missing here? Works in Windows but not in DOS.
> I checked through all of the FAQ's on the Dell website to no avail.
> Anyone have any ideas?
> The computor is a 450mhz Intel system with a Trident video card. Dell
> D1025HT monitor. Carey
>
>
>
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