Monitor Problem

[johnc12]

Helow guys,

i have here in our office an AOC 14" color monitor model 4vn. the screen suddenly turns white and blurred when use for at least 45mins. one of my friend told me to replace the cap near the flyback. so i replaced the 47uf 200V cap to which i think is the problem. after that i tried to connect it back to my cpu but a new problem occur. the monitor turns on but the power led suddenly turns orange (means off). the other 8 leds is just blinking. what could have cause the problem.... ???? i hope someone can help me. i also try to find some service manual and schematics on google but the picture is so unreadable. any help is appreciated... if you have some question please do ask. thanks... 

 

[ante1]

Hi John,

An orange power led often means

 

[ante1]

Hi Doc,

Yeah, hungry for current!  ;D

 

[johnc12]

i'll try checking the supply and feed it... haha thanks ante

 

[johnc12]

by the way. i didn't touch any component in the PSW. The one I replaced in on the flyback the capacitor 47uf 200V on pin 3. When i turned it on not connecting the video cord on my cpu the monitor power led and other 8 leds are all in standby mode. But when I connect the video cord on my motherboard the problem that I stated on my first post occur.... I hope this doesn't sound confusing guys. hehe.. ante? hehe

 

[ante1]

Try to measure the Mosfet sitting close to the flyback!

 

[johnc12]

hmm... ante i found the mosfet near the flyback and but  i'm kinda confuse on how to test the irf630a while it is on the pcb. I'm also afraid to desolder it using my handheld pump and 40w iron. Hope you could help a newbie... 

 

[ante1]

If you

 

[johnc12]

Yah thanks for that. I was planning to use my broken tip 60 watts solder on it. And i'm kinda hesitant to do so. I also found some site that shows a particular problem like mine, but the monitor model is different. The problem is pointing to the same parts as what you've said. It says that I have to check IRF630A (problem shorted), capacitor 150uf 400v caps and R720 (9.3k) but my R720 is 100k near the flyback and see if it is burned but it is not.  ;D

I don't know if it still has something to do with my video cable not connected or connected to the cpu.  ??? I'm still confuse of it.. But thanks for the help ante... 

 

[ante1]

If your monitor has a second input connector of some kind you can try another input source. This way you can establish if the problem has to do with the input or not.

 

[johnc12]

ante, what do you mean by input connector? All I have here is a video in and AC power in.  ???

 

[srich70546]

In the past I have found that the caps in the 160v line will cause many out of the ordinary probolems.

 

[ante1]

Well, I mean like a CVBS (composite video) or other besides the standard 15-pole connector.

 

[johnc12]

mr rich did you mean all ceramic and electrolytic caps near the flyback????

ante, do you want me to replace CVBS and check video in circuit in the monitor right?

i'm still working in the flyback area and havent replace anythin yet. But I will post any progress. I'm off every sat and sun.... I cant work it this days....  ;D

 

[ante1]

I meant try to use another signal source (if you got an input for some) to establish if the problem is still there!

 

[johnc12]

yes i tried it with my old motherboard and also with new ones... and the same problem  occurs... I still  haven't tried  to replace the mosfet... I think tomorrow and I will post here what happend....