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eusus
Joined: 12 Nov 2007 Posts: 2
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Posted: Mon Nov 12, 2007 1:39 pm Post subject: pls help nokia and samsung monitor problems |
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hi everybody, i need help with 2 monitors, one with a more serious problem
NOKIA 446F (NOKIA 446 PRO)
at first the image began tu shrunk vertically, i openned the monitor and saw that stv9397 VERTICAL DEFLECTION
BOOSTER was giving the problem. as i was moving the part, th image came back to normal. still the image wa blurry a
bit. anyway i looked for the part , replaced it and...the monitor doesnt turn on anymore. i mean the led in front
tunrs green for a sec or two and then back red. what seems to be the problem?
and the second:
SAMSUNG SYNCMASTER 900IFT
there were some problems with the socket where the cable from the video signal enters the monitor, the colors were
chenging from time to time. i checked the soldering , fixed and for some days it was ok. now it does the same thing,
only that to a smaller scale. i mean the colors affected are less obvious i mean like light blue turns white or
viceversa, could be the same thing? and morething whics dazzles me. as i was washing the screen with a piece of
cotton and plain water i discovered that the protecion pelicula on the screen comes off. i mean, im not scrubbing or
smth, and it comes off...that would be ok but i discovered that the screen produced an electrical shock of a medium
intensity, What should i do? what is that thing that comes off? some kind of a protection? |
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torbjorn
Joined: 07 Jun 2007 Posts: 370 Location: Sweden
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Posted: Tue Nov 13, 2007 9:01 am Post subject: |
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Most strange faults on Nokia monitors are caused by bad solder joints that often are difficult to see. For example, cracks in the joints of SMD resistors and capacitors are common. If you don't want to resolder the whole chassis, do a thorough inspection with very good light and a magnifying glass. If the PCB is dirty (flux residues etc), it might be a good idea to wash it with methylated spirits and a stiff brush before the inspection. On some of them (particularly, the older ones made in Finland), bad electrolytic capacitors are also common.
The coating on the screen of the Samsung monitor is intended to deviate the electric surface charges to the grounded fixing frame of the CRT, in order to avoid dust accumulation on the screen and to comply with the radiation regulations (MPR-II, TCO etc). That coating is there on almost all CRTs for computer monitors manufactured from the early nineties and to today. But i have never heard of a such coating flaking off before!
As a comparison, CRTs for televisions don't have a such coating. |
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eusus
Joined: 12 Nov 2007 Posts: 2
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Posted: Tue Nov 13, 2007 9:05 am Post subject: |
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thanks for the answer, but still...why is sending electric shocks when i touch the screen? when i turn off the monitor i see the current flowing for about 1 inch in different places on the left side. if i touch it i feel it, nor verry intense like 220, but strong. what can i do? is the monitor useless? is theree anyway i can fix that?
thanks |
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torbjorn
Joined: 07 Jun 2007 Posts: 370 Location: Sweden
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Posted: Tue Nov 13, 2007 9:42 am Post subject: |
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The reason for the shocks is that the inside of the glass is charged with the monitor's EHT (around 25-30 kV).
You will experience the same shocks off the screen of an ordinary television, immediately after switching it on or off.
A older monitor (manufactured before about 1991) also gives shocks in this manner even if everything is in order.
I think you can continue using the monitor, just don't touch the screen and keep small kids away from it.
I have heard of antistatic sprays that are claimed to be useful to fix such problems, but never tried them. |
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