Tuesday, July 28, 2015

LG W2243T-PF Monitor (NOT) Fixed

Position of capacitors on the power board
From this ebay listing
This was going to be a success story.  My monitor went dark (well, it just flashes the LG logo, then the display, then goes dark--it does with 2 computers).  This was actually a refurbished model that LG sent me to replace another (different model) that went dark about 3 years ago.  This one was originally manufactured in 2009, according to the sticker on the device.

This repair is something I never would have considered until I began my electronics hobby at Christmas 2013.  I didn't even know how to solder until a few months after that. Now, after numerous blinking light and other educational projects (see the rest of this blog), I had the opportunity to do something useful.

Unfortunately, this repair did not do the trick--so either something else is wrong. or I did not fix it properly (I think the former, because there is no change in the monitor's behavior, but I'm perfectly willing to accept blame.  But this was educational, and only cost me about 50 cents US in parts to apply.

I was aware that faulty capacitors were probably the cause, so I found the ebay listing above, for a "repair kit" and a couple of YouTube videos.  The ones where it all goes smoothly are not very useful, because things rarely go smoothly.  I found one where the author struggled to get the case open and that's the real challenge. Find it here. I killed my fingers, as the author indicated, and the final push required the gentle insertion and twisting of a screwdriver, but I got it open.

Note: the author of that video only wanted to remove the stand.  To someone remove the capacitors after having an easier time opening then monitor, try this one.

Once it was open, the rest was fairly straightforward.  I marked the location of the wires I disconnected, and removed the housing, which was taped on. I was then able to remove the circuit board for the power supply (4 screws), turn it over, and see that some of the capacitors were bulging, showing signs of stress. Since I had appropriate replacement capacitors in the 125 assortment in  this kit on ebay, which cost about the same as the repair it, which only had 6 capacitors (so I still have some subset of the 119 remaining capacitors).
Open, turned over, housing marked to id wires for replacement
Housing opened and turned over
Circuit board removed. Note bulges on some capacitors

The capacitors on the board were 1000uf 16V and 470uf 35V, all 105 degrees C.  Mine were the same, except that the 470ufs were 50V.



Capacitors removed

Desoldered Board

New Capacitors in place