Picture goes out
This problem is a widespread one with the Sharp LC-32D40U and has apparently been acknowledged in a Sharp Service Bulletin (which I have not seen). 6 screws that attach the inverter board to the LCD gray metal bottom loosen over time, causing the TV to periodically lose video while retaining audio. Sometimes turning the TV off and on again restores video, sometimes not. The problem gradually gets worse making the TV unusable.
The best solution for most TV owners is to get Sharp Customer Service to send someone out to fix this problem free of charge, as reported by FixYa's kmhav52 and sz422 (10/16/2008). kmhav52 says that his TV was out of warranty, but Sharp still agreed to fix it. I don't know whether this is Sharp's current policy, and it might take some pressure and a number of calls to get this outcome.
If you decide to fix the TV yourself, as I did, the good news is that there are no parts to buy and the fix is easy and quick, . The bad news is that disassembling/reassembling the TV is neither easy nor quick. The following instructions, however, should help make your disassembly/reassembly much easier than mine was. I am writing them from memory, so don't be surprised if they are not exactly correct or I miss something.
My first advice is to obtain a copy of the LC-32D40U Service Manual. I got mine as a PDF document from Manualsparadise.com for $25. You only need 3 pages: J-1 and J-2 give Mechanical Exploded View diagrams and K1-1 gives the Mechanical Replacement Parts List that tells you the name of the part referred to in the Exploded View diagrams. For easier reading I scanned the diagrams on J-1 and J-2 and expanded them onto 5 separate pages. Each page I created shows in order a different step of the disassembly.
1) Stand Assembly - the top middle and left diagrams of J-2
2) Back Cabinet Assembly - the top diagram of J -1
3) Angle Back Assembly - the top right diagram of J-2
4) LCD Cover Assembly - 2nd up from the bottom diagram of J-2
5) LCD Bottom with Inverter Board - the bottom diagram of J-2
Lay the TV face down on a table covered with soft material.
1) Stand Disassembly
Remove the 4 screws holding the stand on with a hex driver. Remove the stand.
2) Back Cabinet Disassembly
Using a #1 Phillips screwdriver (preferably magnetized), remove the 16(?) screws around the edge of the back cover indicated by arrows molded into the cover. The Exploded View diagram labels them 208s. Remove and keep separate the two screws in the center of the back cover (a different size labeled 204s). Remove and keep separate the screw holding the on/off button unit (different size labeled 205). Lift off and remove the back cover.
3) Angle Back Disassembly
I hoped to see the inverter board when I removed the back cover. No such luck. Next you need to remove angle backs 2 and 1. The angle backs are the metal parts that support the stand and run down the middle of the TV. Each is labeled with a stamp in its metal. Four 202 screws hold down angle back 2. Three 202 screws up top and 2 209 silver-topped screws hold down angle back 1. Also in the back two 202s hold angle back 1 in from the side. Remove both angle backs.
4) LCD Cover Disassembly
We are getting close, but this is the most challenging disassembly step. Loosen but don't remove the four 207 screws that hold in the side spring clips. Remove the eight 209 silver-topped screws that hold the cover down. Remove the 2 screws holding down the on/off button unit and remove the unit itself. This exposes a 202 screw coming in from the side. Remove it and the 3 other 202 screws coming from the side, 2 on top and 2 on the bottom.
The LCD cover should now be free, but it cannot be removed without undoing some connections. Remove or cut the grey tape (labeled 124 in the Exploded View) on the top side middle that seals the cover to the LCD. The three wires to the bottom left speaker must be disconnected. Pull out the white plug connecter. Slide off the red and blue wires by depressing the little metal tab that locks them in. There are two ribbon connections in the middle of the LCD cover that also must be disconnected and pushed down through the metal **** in the cover. One requires that you cut the cable tie that connects it to a black plastic ring. Pull it off gently and slide it down the ****. The other is very thin but also pulls off. Now the cover can be lifted off and moved about 8 inches to the right.
5) LCD Bottom with Inverter Board
Once the LCD cover is removed, on the left side you can see the metal cover of the inverter board and the six screws holding it down, the very screws that we have been looking for! Remove the six screws and the metal cover. Without disconnecting any of its connections, rotate the inverter board up and to the left to expose the bottom of the inverter board as well as the gray metal bottom of the LCD to which the inverter board is attached and grounded. Note the 3 copper rectangles on the bottom of the inverter board surrounding the 3 screw holes away from the left edge towards the middle of the TV. These are the grounding strips that lose their connection.
Using contact cleaner (I got mine at Micro Center) clean off any black burn marks from these connectors. Also clean all black marks from the grey metal bottom that they contact. Clean carefully and thoroughly. You might need to scrape lightly to remove all marks.
Rotate the inverter board back in place. Line up the metal inverter board cover. You can either use the 6 existing screws (I did) or purchase replacement screws (I was told that the improved screw part number is LX-BZ2315TPZZ). Using a removable threadlocker (I used Loctite Blue from Home Depot) coat the screw threads of one screw. Tightly screw in the middle edge screw first. Follow this by the edge top and bottom screws, then the middle inner screw, and finally the top and bottom inner screws, using the threadlocker on all 6 screws. Verify that all screws are tight.
Reassembly is the reverse of disassembly with the advantage that you have been there once before. As long as you have kept all your parts separated and follow the exploded view diagrams, it should be easier and quicker than the disassembly. Remember to reconnect all the connections that you disconnected. I used a new cable tie to replace the one I cut. Be sure that all screws return to their proper places.
7) If your experience is like mine, you will discover that the problem is fixed. My set used to go black several times an hour. And sometimes it was hard to get it to show video again. So far this week after fixing it it has not gone black once.