Guest
Here's the problem, and what I have seen about it...
Before all, I must say that I did a lot of research on this problem in Sam's
Repair FAQ, and found that the problem is something with retrace lines...
But I don't know what, so I'll ask here...
OK, problem is like this... My monitor was very often online for a few days
(more like week, two or so)... And, since I wasn't at home for a weekend, I
turned it off... And, today, I turned it back on, and here ya go - I see
some lines dancing on the black background...
So far I've seen about these lines - if I lower the brightness to 0, lines
are very visible... And, if I raise brightness to 100, I almost can't see
the lines... I tried whacking the monitor, but no use...
I opened it, used a hair-dryer (hot air) and a rubber stick (bumping
capacitors and other components) trying to locate cold solder joints, but, I
couldn't find any...
So, browsing through www.repairfaq.org, I've found that these could be the
problems (copy paste):
---------------------
Screen (G2) or master brightness/background/bias control - mark setting and
then see if a slight adjustment removes the retrace lines. See the chapter:
"Monitor Adjustments". Of course, if this happened suddenly, the problem is
not due to a misadjusted control though a dirty pot is possible - turn it
back and forth - this might clean it and restore normal operation.
Power supply or connection to CRT neck board - insufficient voltage will
result in the CRT never totally blanking. Check (usually scan derived) power
supply components (from flyback).
General power supply - check B+ for correct value and ripple. A main power
supply fault might result in these symptoms (and usually many others).
Blanking circuit - this may be a part of the video/chroma chip or separate.
Check waveforms to determine if the blanking pulses are making it to the
video output.
---------------------
I didn't try nothing around G2 pot, but I must ask following question... Is
it possible that simply the problem is in this pot, and if I turn it a bit
and return it to it's original position, the problem could be gone? I mean -
I suspect at the worn pot... ?
Power supply - I don't know... I could try with screen breathe tests...
Nothing - the frame is rock-solid... I guess the power supply is not the
problem... Something in horizontal deflection should be the problem, I
guess, because I can see diagonal lines (shaped this way '/')... And some
bacground blinking is visible...
And, yes, sometimes the screen simply goes to some kind of blueish black
background, and blinking is still visible... I don't know how to describe
it... It goes blueish just for a moment, and then goes back to black
background...
Any help to this monitor? I am planning to let the guys from repair-shop
take a look at it... But, I'd just like to know what is happening to ti... I
like this monitor very much, and I don't know if I will find anything
similar if this one dies...(((
Thanks to all good people...
--
"Brezuljkasts li gledalisteu njuku ?" upita kokakolaa pipa skakavacu
komponiru. "Nisam ja nikog bombardiro !" rece Klinton ljubi "Ja samo
snajperisto kolje zagadjenm !" By runf
Damir Lukic, calypso@fly.srk.fer.hr
a member of hr.comp.hardver FAQ-team
Before all, I must say that I did a lot of research on this problem in Sam's
Repair FAQ, and found that the problem is something with retrace lines...
But I don't know what, so I'll ask here...
OK, problem is like this... My monitor was very often online for a few days
(more like week, two or so)... And, since I wasn't at home for a weekend, I
turned it off... And, today, I turned it back on, and here ya go - I see
some lines dancing on the black background...
So far I've seen about these lines - if I lower the brightness to 0, lines
are very visible... And, if I raise brightness to 100, I almost can't see
the lines... I tried whacking the monitor, but no use...
I opened it, used a hair-dryer (hot air) and a rubber stick (bumping
capacitors and other components) trying to locate cold solder joints, but, I
couldn't find any...
So, browsing through www.repairfaq.org, I've found that these could be the
problems (copy paste):
---------------------
Screen (G2) or master brightness/background/bias control - mark setting and
then see if a slight adjustment removes the retrace lines. See the chapter:
"Monitor Adjustments". Of course, if this happened suddenly, the problem is
not due to a misadjusted control though a dirty pot is possible - turn it
back and forth - this might clean it and restore normal operation.
Power supply or connection to CRT neck board - insufficient voltage will
result in the CRT never totally blanking. Check (usually scan derived) power
supply components (from flyback).
General power supply - check B+ for correct value and ripple. A main power
supply fault might result in these symptoms (and usually many others).
Blanking circuit - this may be a part of the video/chroma chip or separate.
Check waveforms to determine if the blanking pulses are making it to the
video output.
---------------------
I didn't try nothing around G2 pot, but I must ask following question... Is
it possible that simply the problem is in this pot, and if I turn it a bit
and return it to it's original position, the problem could be gone? I mean -
I suspect at the worn pot... ?
Power supply - I don't know... I could try with screen breathe tests...
Nothing - the frame is rock-solid... I guess the power supply is not the
problem... Something in horizontal deflection should be the problem, I
guess, because I can see diagonal lines (shaped this way '/')... And some
bacground blinking is visible...
And, yes, sometimes the screen simply goes to some kind of blueish black
background, and blinking is still visible... I don't know how to describe
it... It goes blueish just for a moment, and then goes back to black
background...
Any help to this monitor? I am planning to let the guys from repair-shop
take a look at it... But, I'd just like to know what is happening to ti... I
like this monitor very much, and I don't know if I will find anything
similar if this one dies...
(((Thanks to all good people...
--
"Brezuljkasts li gledalisteu njuku ?" upita kokakolaa pipa skakavacu
komponiru. "Nisam ja nikog bombardiro !" rece Klinton ljubi "Ja samo
snajperisto kolje zagadjenm !" By runf
Damir Lukic, calypso@fly.srk.fer.hr
a member of hr.comp.hardver FAQ-team