No sound on Sharp Aquos 37' LC-37D4U
Almost all intermittent audio or audio failure problems with Sharp Aquos LC**D4U, LC**D5U, LC**D6U, and LC**D7U televisions are the result of a relatively simple design flaw involving the heatsink pad compound used on the Tripath TA-2024 amplifier chip (IC2502) found on the A/V board. This compound has a fairly low melting point and, over time, tends to seep out from between both top and bottom heatsinks onto the legs of this chip as well as onto circuitry immediately surrounding it. Further, over time the seeping compound also becomes somewhat conductive creating bridges which short the audio amplifier circuit causing everything from intermittent audio to complete audio failure.
Fortunately, in almost every case audio can be completely restored by cleaning the old compound from both top/bottom heatsinks and from both sides of the PC board in the area immediately surrounding the chip (I used rubbing alcohol which worked quite well). Sharp has issued a service bulletin addressing this issue (LCDTV-194) wherein a ‘2502 Heat Kit’ is specified. This kit is Sharp Part Number: PSPKIT663WJZZ and is available from circuitcity.partsearch.com for $19.95. However, it’s entirely possible to get by with the heat pad only, Sharp Part Number: PSPAZA663WJKZ for only $9.95. Please note that board replacement for this problem is almost never necessary, so if you’re working with a repair technician be sure and insist that he/she be certain to try cleaning the old board and replacing the aforementioned heatsink pads before charging you for a new board.
If one is reasonably familiar with electronics disassembly/reassembly and is willing to take their time, this can even be a DIY project. It is possible to find ‘important service references’ by simply entering LC26D4U (the 5, 6, and 7 series are very similar, and this information covers all screen sizes) into the search field at eserviceinfo.com. This will greatly aid in disassembly/reassembly of the TV, as the A/V board is somewhat ‘buried’ under other boards. Please refer to post # 373 at avsforum.com/avs-vb/showthread.php?t=647174&page=13 for pics of the information detailed here.
Particular thanks are owed ‘Aureius’ of the AVS forums for his research efforts concerning this issue !
Jan 25, 2009 |
Sharp LC-37D4U 37 in. LCD Television