Hi,
I 've got a Samtron 78E 17" CRT monitor standing around here. The only
thing it does is faintly displaying random color gradients.
I've uploaded a picture he
http://img297.imageshack.us/my.php?image=monitor7zj.jpg
Can someone tell me where I need to be searching for this kind of
problems? I've already checked the components visually, non of them
appear to be burned out or anything, and I've redone all the soldering
joints. All to no avail, the image on screen remained identical.
Of course I also tried resetting it to factory default settings before
opening it up. The behaviour also isn't caused bij the graphics card,
as it does the same wheter it's plugged in (in several computers) or
with the d-sub hanging loose.
Any help pointing me in the right direction would be appreciated.

Thanks in advance
Jindrich

Looks like the degausser is not functioning. Typical rainbow pattern.

Was this monitor dropped?

--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================

wrote in message
oups.com...
Hi,
I 've got a Samtron 78E 17" CRT monitor standing around here. The only
thing it does is faintly displaying random color gradients.
I've uploaded a picture he
http://img297.imageshack.us/my.php?image=monitor7zj.jpg
Can someone tell me where I need to be searching for this kind of
problems? I've already checked the components visually, non of them
appear to be burned out or anything, and I've redone all the soldering
joints. All to no avail, the image on screen remained identical.
Of course I also tried resetting it to factory default settings before
opening it up. The behaviour also isn't caused bij the graphics card,
as it does the same wheter it's plugged in (in several computers) or
with the d-sub hanging loose.
Any help pointing me in the right direction would be appreciated.

Thanks in advance
Jindrich

I've tried to degauss it by placing it face to face with another
monitor and repeatedly degaussing the other one (I've read that should
degauss both monitors), and haven't noticed any difference.
A drop was also my first suspicion, but my sister (it's her monitor)
claims it just started up like this one morning. I've got no way to
verify the truth on that, so I can't say for sure.

I doubt that would work,,,who knows! LOL


--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================

wrote in message
oups.com...
I've tried to degauss it by placing it face to face with another
monitor and repeatedly degaussing the other one (I've read that should
degauss both monitors), and haven't noticed any difference.
A drop was also my first suspicion, but my sister (it's her monitor)
claims it just started up like this one morning. I've got no way to
verify the truth on that, so I can't say for sure.

Any suggenstions on how to find out wether the degaussing is
functioning properly then? I can't see the OSD menu, so I can't make
the monitor degauss itself...

writes:

Any suggenstions on how to find out wether the degaussing is
functioning properly then? I can't see the OSD menu, so I can't make
the monitor degauss itself...

Does it display a picture that is normal except for the colors?

If not, degauss is NOT the problem.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Nope, the screen keeps displaying an image similar to the one I posted
a link to. There is nothing even resembling the image that should be
on-screen.
The color patterns change slightly when connected to a pc set to
display different images, but essentially all you get is a rainbow (not
nearly as bright as the one in the picture BTW, I increased the
contrast of the photo so it would be better visible).

Any input as to what the problem may be then?

writes:

Nope, the screen keeps displaying an image similar to the one I posted
a link to. There is nothing even resembling the image that should be
on-screen.

The color patterns change slightly when connected to a pc set to
display different images, but essentially all you get is a rainbow (not
nearly as bright as the one in the picture BTW, I increased the
contrast of the photo so it would be better visible).

OK, it has nothing to do with degauss. If the only problem were incorrect
or lack of degauss, the display would have wrong colors that varied across
the screen, but there would still be a recognizable picture.

Can you take a photo of the entire screen?

Do the user adjustments do anything?

From the photo you provided, I can't even tell if it's got a raster or just
some random blotches of color.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

Here are some better pictures. I marked the corners of what should be
the viewing part of the screen with red crosses. The patterns are only
clearly visible in a dark room, so it's not that easy to make a clear
picture of them.
http://img465.imageshack.us/my.php?image=img32677qn.jpg
http://img465.imageshack.us/my.php?image=img32668qv.jpg
The screen alternates between these two patterns with the d-sub cable
disconnected. According to the manual the screen should be performing
some self-test when disconnected from the computer, I'm assuming that
those alternating patterns correspond with different output I should be
seeing during the self-test.

Jindrich

wrote in message
oups.com...
Hi,
I 've got a Samtron 78E 17" CRT monitor standing around here. The only
thing it does is faintly displaying random color gradients.
I've uploaded a picture he
http://img297.imageshack.us/my.php?image=monitor7zj.jpg

Hard to say, but for want of a better explanation it looks like the CRT's
vacuum could have been lost. If so, the monitor is scrap. Has the monitor
been dropped or roughly handled? It's a long shot but I've seen a similar
thing once before.

Dave

I forgot to reply about the user controls: they are all controlled by
an OSD menu on this monitor, and I can't see it. I pressed the 'menu'
button for 10 seconds, which should have reset the monitor to factory
defaults according to the manual. I think that's all I can do for now
about the user adjustments.

wrote:
Nope, the screen keeps displaying an image similar to the one I posted
a link to. There is nothing even resembling the image that should be
on-screen.
The color patterns change slightly when connected to a pc set to
display different images, but essentially all you get is a rainbow (not
nearly as bright as the one in the picture BTW, I increased the
contrast of the photo so it would be better visible).

Any input as to what the problem may be then?



Sounds like a deflection circuit failure is causing the beam to hit the
inside of the tube somewhere rather than the screen.

wrote:
I forgot to reply about the user controls: they are all controlled by
an OSD menu on this monitor, and I can't see it. I pressed the 'menu'
button for 10 seconds, which should have reset the monitor to factory
defaults according to the manual. I think that's all I can do for now
about the user adjustments.




No matter, the monitor is broken and will need to be fixed before the
user adjustments are of any use.

"Sam Goldwasser" bravely wrote to "All" (19 Jan 06 11:44:08)
--- on the heady topic of " CRT Monitor with weird random colors"

SG From: Sam Goldwasser
SG Xref: core-easynews sci.electronics.repair:355807

SG writes:

Nope, the screen keeps displaying an image similar to the one I posted
a link to. There is nothing even resembling the image that should be
on-screen.

The color patterns change slightly when connected to a pc set to
display different images, but essentially all you get is a rainbow (not
nearly as bright as the one in the picture BTW, I increased the
contrast of the photo so it would be better visible).

SG OK, it has nothing to do with degauss. If the only problem were
SG incorrect or lack of degauss, the display would have wrong colors that
SG varied across the screen, but there would still be a recognizable
SG picture.
SG Can you take a photo of the entire screen?

SG Do the user adjustments do anything?

SG From the photo you provided, I can't even tell if it's got a raster or
SG just some random blotches of color.


It could be an open or a short either inside the CRT or in the
FBK/Focus/Divider. A nearly impossible thing is that the yoke might
have slipped off or a rubber wedge fell off tilting it.

A*s*i*m*o*v

.... You mean 15" sparks are SUPPOSED to come out of this thing?!?

Kinda looks like the rainbow pattern ya get when you loose vertical
deflection on the some of the Philips TV's.

The beam scatters along the edge of the CRT and creates a similar pattern
like yours.



--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

========================

wrote in message
oups.com...
I forgot to reply about the user controls: they are all controlled by
an OSD menu on this monitor, and I can't see it. I pressed the 'menu'
button for 10 seconds, which should have reset the monitor to factory
defaults according to the manual. I think that's all I can do for now
about the user adjustments.