Re: Philips 190S LCD power problem

I have been given a freebe monitor. With all freebe's come problems. My display will turn on for 4 seconds but then the backlights turn off. I can see the icons on the desktop with a flashlight. I would think it is an inverter problem. What does the board think????

Re: Viewsonic VP201b power supply option

Replaced caps on the power supply. Got correct voltage out. Back lights come on and I get a solid blue screen with no graphics or characters displayed. Reseated ribbon cables to no avail. The monitor worked before repairing the power supply. After repair and reassembly I now get a solid blue screen. Getting aggravated with the display. Any ideas. Has to be logic board.

Re: Viewsonic VP201b power supply option

C108 is reading low as well. This display is 5years old after all. I guess all the years of use has taken its toll on the caps.

Re: Viewsonic VP201b power supply option

The resistor checked good @.4ohm rated 0.36ohm. c105 reads 15uf should be 22. and c101 reads 127uf should be 150uf. Checked my meter with some new caps in my shop it seemed to be accurate. Fluke 179 has always worked good for me. C106 is a surface mount, just don't think that i will be able to take that one off to check.. Thanks for the tips. All these caps reading low might just be my problem? maybe? got a reading of 2.5vdc when power supply was loaded and it ramped up to 18vdc when unloaded. Please excuse my A.d.d When a thought comes to...

Re: Viewsonic VP201b power supply option

The caps measured as follows 150uf =127uf 47uf=30uf 150uf=127uf 680uf=621uf taicon and nichison caps

Re: Viewsonic VP201b power supply option

A little help please with locating the components. Current sense resistor, power cap, starter cap.

Thanks...

Re: Viewsonic VP201b power supply option

Thanks for some direction. I will check those readings tomorrow. A bad cap might just explain the fact that the output voltage slowly ramps up when a/c is applied. Again thanks for the direction! I will report back with what I find.

Re: Viewsonic VP201b power supply option

I would like to repair the supply. When I checked the caps the values were within about 10%. The shockley diodes checked good as well. Kinda of stuck at this point, that's why I was going to rig up an external supply. Any pointers would be appreciated!

Trying to troubleshoot the power supply on this display. No power out of the switching power supply. Removed all caps and checked and found all in specs. The specs for the power supply are 18vdc 3.3a. I found a 18.5vdc 4.9a external supply. Would this fry the other boards in the display if I were to use it? I have a bench power supply to test the display and it worked great on 18vdc bench power. Just worried about the extra .5v