LCD Monitor Problem

[Guest]

Hi.. My ViewSonic LCD monitor was working fine for almost 2 years, recently i switched the location of the PC and had to remove all cables and relocate, now the problem is, i have to turn on and off for at least 5 to 6 times to start the monitor, it appears then the screen goes blank... after five or 6 times. its ok.. but with a buzzing sound from inside the monitor.

 

[paulbtorrent]

Hi,
The CCFL tubes behind the plate are weaking or the circuit providing the current to the tubes has weaken ! The tubes on an LCD require 750v to spark up and then run on much lower ( comparable to starting a car !) see page http://www.byfort.com/ccfllamps.htm and tech page, to fix yourself see page http://www.lcdparts.net/howto/troubleshooting/LaptopCCFL1.aspx. The buzzing is a mini version of the kitchen strip light [===========] when it is failing. Ebay sell the tubes. Sometimes poor earthing can effect equipment, no harm in trying the old settting , just the monitor. If you take it apart and replug back together
less the caseing and plate and plate holder, you will be able to see which of the 4 tubes needs replacing.
240v ---> [inverter]&{========}, & {========} to see which one
pc--> vga cable --->[vga] to stop power save mode switch in and use on/off buttons [oooo].

The inverter has high voltage and current, with large capacitors that hold a charge for days. Though if you just checking and changing tubes there no need to work on it, but keep it on a non conducting surface to stop short circuits and hands to edge of board else !. Else need to discharge the capacitors first using a 30k 10 watt resistor wired to drain charge away
}<--plastic screw driver--30k10watt---plastic screw driver-->{ {} being capacitors, see page http://www.acmehowto.com/howto/appliance/freezer/check/capacitor.php, if you have a voltage meter you can read before and after, ok less than 1 volt.
To open caseing after removing any screws use a plastic phone card to slide between the [|] save on screwdriver damaging casing, can be difficult, but does work.