problem in sun GDM 20E20

[[email protected]]

i hv two Sun GDM 20E20 monitors sm time ago i got problem in both
monitors.
when it was running suddenly red color go off. there is only blue
color now and in second monitor there is only red color. wht may
be the problem ??
plz help me!!!

 

[James Sweet]

i hv two Sun GDM 20E20 monitors sm time ago i got problem in both
monitors.
when it was running suddenly red color go off. there is only blue
color now and in second monitor there is only red color. wht may
be the problem ??
plz help me!!!

Does red work in the OSD or is it missing there too?

 

[Jerry G.]

This may be a signal loss in one of the video processing stages. You would
have to go through the video paths with a scope to see where the signal loss
is. There are many components that can cause a failure as what you are
describing. The fault can be a failing component or an intermittent solder
connection.

I would suggest giving out the monitor for proper service. Considering its
age, it may not be worth the cost.

--

Jerry G.
======


i hv two Sun GDM 20E20 monitors sm time ago i got problem in both
monitors.
when it was running suddenly red color go off. there is only blue
color now and in second monitor there is only red color. wht may
be the problem ??
plz help me!!!

 

[Andrew]

i hv two Sun GDM 20E20 monitors sm time ago i got problem in both
monitors.
when it was running suddenly red color go off. there is only blue
color now and in second monitor there is only red color. wht may
be the problem ??
plz help me!!!

Probably a dead resistor on the neck board. IIRC there is a divider
resistor for each color on the board. The other less repairable fault is
dead emission in the tube, you can partially bring them back to life
with a regenerator box. tapping the neck and the video drivers can
detect a dry joint which is also a possibility. If you don't have
experience doing HV repair don't touch these monitors.

Andrew

 

[rush14]

Probably a dead resistor on the neck board. IIRC there is a divider
resistor for each color on the board. The other less repairable fault is
dead emission in the tube, you can partially bring them back to life
with a regenerator box. tapping the neck and the video drivers can
detect a dry joint which is also a possibility. If you don't have
experience doing HV repair don't touch these monitors.

Andrew

I had a monitor with the same symptom after it had been in use for
about 2 years. Whacking the side of it would cause the colors to
flicker. Found a transistor with a cold solder joint in the area
Andrew (above) mentioned. Again, be careful around that high voltage.
Rush.

 

[[email protected]]

i hv checked for cold solder but i hvn' found any cold solder .
i gave my monitor for repairing in my city but he couldn't found exact
problem in it .
he told me there is problem in color processing IC. but i don't know
which IC processes the color.

I think tube is ok bcoz i hv changed the board which connected to back
of tube.
when i interchange the board the problem is also interchanged.

Can any buddy tell me which IC may be faulty

thanx in advance every buddy

 

[[email protected]]

red is not working in OSD

 

[James Sweet]

red is not working in OSD

Sounds like this monitor uses an IC to drive the cathodes directly, this IC
has apparently failed. Is there a large heatsinked IC on the neck board?

 

[Andrew]

i hv checked for cold solder but i hvn' found any cold solder .
i gave my monitor for repairing in my city but he couldn't found exact
problem in it .
he told me there is problem in color processing IC. but i don't know
which IC processes the color.

Its a monitor not a TV, so no color processing IC as such. In the ones I
serviced there is basically various boards with the 75 ohm in that would
then connect onto the board at the back of the monitor with various
video amplifier chains some using video amplifier blocks others using
transistors these would then make their way onto the neck board and into
the tube. You can isolate the amplifier chain by swapping the BNC in
lines. And if it is known dead then trace through the above chain with a
color pattern, which you can load off the net.Another resource is the
S.E.R F.A.Q. from this group.

I think tube is ok bcoz i hv changed the board which connected to back
of tube.
when i interchange the board the problem is also interchanged.

Can any buddy tell me which IC may be faulty

thanx in advance every buddy

Andrew

 

[[email protected]]

hello Andrew

there is two IC one is CXA 1907S (SONY) and other is FA1401 (HITACHI)
(with large heat sink)
can be problem in one of them IC??
cause the signal goes to CXA1907S directly
plz tell me abt it.

thanks

 

[Sarason]

hello Andrew

there is two IC one is CXA 1907S (SONY) and other is FA1401 (HITACHI)
(with large heat sink)
can be problem in one of them IC??
cause the signal goes to CXA1907S directly
plz tell me abt it.

thanks

Just redirect the interconnect leads to isolate the problem.

Andrew