Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

[GoneGault]

When I got this monitor, the blue power light would come on, but there was no display. When I checked the power supply, there was the usual group of suspects...several obviously bad Xunda capacitors. I could replace them, but I am concerned about the scorch marks on the board; I have never fixed one with so much heat marks. Are the heat marks anything to be worried about?

[budm]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Bad caps causes the inverter circuit to run hot due to high frequency AC ripple.
You need to check the SMD MOSFET Q6, Q6 to see if they are not shorted out or has low Ohms (<100), especially the Source and Drain pin.

[GoneGault]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Thanks for the reply BudM. Q5 and Q6 readings are 146 Ohms.

[budm]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Between Source and Drain? If that is the case, you will have to remove them off the board and measure them again.

[momaka]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Let's see... 9 capacitors and two (possibly) bad MOSFETs.
Worth saving?
- I sure think so .

...
Oh yeah, there's also a ceramic fuse you need to check. It's more or less in the center of that first picture you posted - just above the heat sink, and right below jumper JP1. It's marked as "T3.15A/250Vac". If it's blown (that is, you don't get any continuity across or you get a high resistance), the MOSFETs may be bad too.

Still a fairly easy fix, though.

[GoneGault]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Not all of my efforts have a positive outcome, but I replaced the bad capacitors and it started right up! Thanks for the info guys!

[budm]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Good news.

[momaka]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Yay!
Enjoy

[Keiningham]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

I too have a KDS 22 inch monitor (actually two) - K-2237MDWB not functioning correctly - similar problem to GoneGault. The problem is identical on both but occurred at different times. I changed their us from a PC computer to a Mac and in the beginning they were working fine. However, I went in the system settings and forced the monitor to turn off and it never came back on. The same happened on the 2nd monitor. The monitors turn on (blue light) but they do not detect an incoming signal on any input. I would like to save them, if it is a simple and reasonable repair. Any thoughts?

[momaka]

Re: Worth saving? KDS K-22MDWB 22" widescreen LCD monitor

Hi, Keiningham. Welcome to badcaps.net

Since your monitor appears to be a different model, I suggest you start a new thread and post some pictures of the boards inside it. This is the best way for us to tell what the problem might be. Most monitors require just a recap job, which is fairly simple.