Intro: How to Repair a Westinghouse L1975NW 19" LCD Monitor
The Westinghouse L1975NW monitors seem to have a common failure point and this Instructable will show you have to repair this problem. If your monitor has either a blinking power LED or no power at all then this should be the solution to get it back up and running. To complete this repair you will need the following:
Tools:Phillips screwdriver, flat blade screwdriver, soldering iron, de-solder braid and a pair of tweezers.
Parts: Qty 2 40T03GP MOSFET, Qty 2 220mf 25v capacitor, 1 4amp pico fuse (surface mount)
We have a kit of all parts needed on our web site http://www.ccl-la.com/catalog/product_info.php?cPath=21_35&products_id=28
If you don't have a monitor to repair check Ebay.com, you will find them for sale usually for less than $30 in as-is condition, just be sure the screen is not cracked.
This repair guide also works for the Acer AL1916 and the Gateway Gateway FPD-1830 as these are the same monitor on the inside.
Step 1: Back Cover Removal
First we need to remove the back cover. You can start by removing the stand, pull the little cover off the screws and remove the 4 screws under the cover. Next remover the signal cable. Now remove the 4 screws one in each corner as shown in the photos. The next step is separating the two halves of the case. Start on the side of the screen and insert the flat blade screwdriver between the front and back halves. If you apply a little pressure with the case should separate a little bit, now just work your way around the monitor. When you get to the bottom you will need to unplug the two speakers from the control board before the case will separate.
Step 2: Getting to the Electronics!
Now that the plastics have been removed we need to get to the power supply board. Turn the monitor over face down. Remove the ten screws and nuts as indicated by the yellow arrows, and unplug the backlight tubes - red arrows and remove the metal shield. You will see the power board on the left and the driver board on the right. Unscrew the power supply board and remove it from the reset of the unit.
Step 3: Lets Do Some Soldering!
With the power board out we can see the blown capacitors that are the cause of the problem ( the 2 parts marked by yellow squares on the right side). When the capacitor go out the damage the MOSFET transistors and that causes the fuse F200 to blow. If you look at the top of the capacitors you should see s slight bulge, that is the easiest way to find damaged capacitors. You will need to replace the capacitors and MOSFETs and the fuse on the bottom of the board. When inserting the capacitors be sure to replace them with the polarity correct, you can see the negative stripe on the side of the capacitor. After the caps and MOSFETS are replaced you will need to turn the board over and replace the fuse marked F200 on the bottom. This where you will need the tweezers because this is a very small fuse, about half the size of a grain of rice.
Step 4: It Works! ! !
After all of your bad parts have been replaced just re-assemble the monitor and test your work. If everything goes as it should then you now have a working monitor.
Be sure to check out our web site at :http://www.ccl-la.com/monitor_repair.htm for repair guides for other monitors. We are adding guides as soon as we get them laid out.
With luck your monitor should now last many more years.
If you have questions please contact me at: