Look for bad caps as you can see in my VIEWSONIC VX series albums. Basic LCD monitor and TV troubleshooting guide: Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you. Or www.digikey.com just make sure to use caps with low ESR, 105c, high ripple current, long life rating such as PANASONIC FM or FC series.
If you are going to DIY and already try the monitor with another PC, and have proper tools and know safety precaution then please read on:
Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply (they should be replaced in a set), blown fuses; poor solder joints, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed VIEWSONIC monitors to get some ideas what to look for: http://s807.photobucket.com/albums/yy352/budm/
Post back what you see inside so we can guide you further and it will help out other people in the future also.
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm/
Please leave rating if it helps.
This power supply board is also used in Viewsonic VX2835W. The main problem are 4 bad/defective capacitors and shorted legs due to bleeding of soldering lead (brownish color).
1. 22uf 400v
2. 47uf 50v
3. 1uf 100v
4. 22uf 35v
You can find them near the PWM IC controller (U601). Replaced all these capacitors regardless they look good. I pulled them out off the board and tested them with my Blue ESR and capacitor tester and found 3 were defective.
Next, you need at least 97% Isoprophyl alcohol and toothbrush to clean the soldering paste. Due to overheating on the primary section / HOT section the soldering leads tend to produce brownish paste which is causing the component parts to SHORT. Concentrate at the back of the board, especially at the U102 (16-pin IC) and Q202 by scrubbing these IC and transistor carefully. I used magnifier to make sure the legs are clean and shiny. Clean the rest of the back and some part on top of the board. Let it dry for 2 hours at least. I did 2 times this cleaning to make process.
On my VX2835W main board has 2 bad capacitors at C124 and C126. I replaced them and cleaned also the board with alcohol.
That's it. Good Luck.
Roan Mac
Computer Tech
Chapel Hill, NC
This power supply board is also used in Viewsonic VX2835W. The main problem are 4 bad/defective capacitors and shorted legs due to bleeding of soldering lead (brownish color).
1. 22uf 400v
2. 47uf 50v
3. 1uf 100v
4. 22uf 35v
You can find them near the PWM IC controller (U601). Replaced all these capacitors regardless they look good. I pulled them out off the board and tested them with my Blue ESR and capacitor tester and found 3 were defective.
Next, you need at least 97% Isoprophyl alcohol and toothbrush to clean the soldering paste. Due to overheating on the primary section / HOT section the soldering leads tend to produce brownish paste which is causing the component parts to SHORT. Concentrate at the back of the board, especially at the U102 (16-pin IC) and Q202 by scrubbing these IC and transistor carefully. I used magnifier to make sure the legs are clean and shiny. Clean the rest of the back and some part on top of the board. Let it dry for 2 hours at least and I did 2 times this cleaning process.
On my VX2835W main board has 2 bad capacitors at C124 and C126. I replaced them and cleaned also the board with alcohol.
That's it. Good Luck.
Roan Mac
Computer Tech
Chapel Hill, NC
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