electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
pls help nokia and samsung monitor problems

 
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs
View previous topic :: View next topic  
Author Message
eusus



Joined: 12 Nov 2007
Posts: 2

PostPosted: Mon Nov 12, 2007 1:39 pm    Post subject: pls help nokia and samsung monitor problems Reply with quote

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?
Back to top
View user's profile Send private message
torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Tue Nov 13, 2007 9:01 am    Post subject: Reply with quote

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.
Back to top
View user's profile Send private message
eusus



Joined: 12 Nov 2007
Posts: 2

PostPosted: Tue Nov 13, 2007 9:05 am    Post subject: Reply with quote

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
Back to top
View user's profile Send private message
torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Tue Nov 13, 2007 9:42 am    Post subject: Reply with quote

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.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs All times are GMT
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


eServiceInfo on FB - Service Manuals Free Download - Service Diagrams

Free TV Schematics Download - HARDW.net - Pinout Master - Jabse Service Manual Search - Jabse.InK  - onTap.bg

SnimkiOt.com - Poblizo.com : пътешествия