8 Aug
2012
8 Aug
'12
10:51 a.m.
Hey everyone, I ma repairing a Sun 100U computer, and am having some
issues I would love some help with. I am using a bwtwo video card with
the Sun 100U CRT (its a 17" HD B&W phillips CRT). I am getting an image
showing a successful boot, but I am getting a split double image (like
split screen but the same image on both sides). Any ideas what is
causing this, a frequency issue? Any jumpers/settings on the video card
which may inadvertently cause this? Could it be a CRT issue?
This sounds to me like a horizontal frequency issue -- the video card is
sending lines at twice the frequency the monitor expects, so each
physicla sweep of the electron beam displays 2 'lines' from the video
card, next to each other.
As to 'could it be a CRT issue', it depends on what you mean by 'CRT'. I
can't see how it could be a problem with the evaucuated glass thing. But
if 'CRT' really means 'monitor' and includes the deflection circuitry,
then it most certainly could be a problem with that.
Questions :
Should this confgiuration work? Are the video card and moniotor the right
ones for htis setup?
Has _this_ set of equipment ever worked? Is it possible osmething has
been modified, for example the monitor adjusted for differnt scan rates
to use it on some other machine?
Can you measure the horizotnal syn freqeucny at the monitor connector and
compare it with whaty it should be (is this value known)? If it's wildly
off, then suspect a problem wit hthe video card or intialisation of same.
If it's right. suspect a problem in the monitor.
-tony