Westinghouse LTV-32W3HD Project....

Discussion in 'The Projects Forum' started by SolomonMan, Jan 24, 2012.

  1. SolomonMan

    Thread Starter New Member

    Jan 24, 2012
    21
    1
    All,
    I have a Westinghouse LTV-32W3HD that when I turn it on the power light on the side quickly turns to blue from orange/yellow, flashes a few times and then stays blue. There is no picture at all. The same thing happens whether the remote or power button on the side of the TV is used.
    I have taken a few electronics course - college level - but they were entry 100/200 level and about 15 years ago. I have read a little on how to test LCD TVs but I am open to any suggestions on troubleshooting (really Open to Learn). I have the user manual and the Westinghouse service manual (no electronic schematic just block schematic), after looking closely on the webpage for it ..the disassembly/block schematic is found here;
    http://elektrotanya.com/?q=showresult&what=Westinghouse%20LTV-32W3HD&kategoria=tv&kat2=all
    I opened the unit up and started with the power supply looking for bad caps with a magnifying glass and everything looked good. There was a light discoloration around one electrical component on the AC side of the Power Supply which I believe is a Triac. I found a website that talked about testing Triacs by using a OHM meter. I did the test and it passed (I believe) from what they suggested. Not sure if the website or I was 100% correct on endeavor. The printed number next to that electronic component (triac?) on the board was Q601.
    I have the below power supply in this TV.
    http://www.shopjimmy.com/westinghouse-psm217-404-r-power-supply-unit.htm
    I tested the following Voltages on the Power Supply while plugged in; (According to what I can make out on the board)
    Standby 5vdc, switched 5vdc, 12vdc, and 24vdc. All voltages tested as expected.
    I inspected the main board and nothing looks out the ordinary, Capacitors look fine nothing looks burned, loose, or discolored.
    There appears to be 3 LEDs spread around the main board. Two are close together (D44/D45) and the last one is D17. The D45 is not on. D17 and D44 are red and on when the TV is powered on.
    I have the following main board;
    http://www.shopjimmy.com/westinghouse-55-3zx01-001-main-unit.htm
    Not knowing if the LEDs mean anything, I moved on to the Inverter board. The VBLs connections all read 24 volts. The BLON reads 5 Volts. I believe the I_PWM gave me a reading of .8 volts one time but to be honest my online reading only mentioned BLON and VBLs being important so I did not focus much on the I_PWM, E_PWM,SEL, and IL_SEL values. I can retest if needed. Can someone clarify what these (I_PWM, E_PWM,SEL, and IL_SEL) connections represent or could be doing.
    I have the the following Inverter Board;
    http://www.shopjimmy.com/cmo-27-d004821-backlight-inverter.htm
    I moved on to the BackLight output from the inverter board. I get nothing, tried another multimeter to make sure, at the highest Volts AC the meters could handle. I backed the meters down... same result. I moved in a ways to the 4 Large Capacitors on the board they all read 24 volts. The two inboard fuses on the inverter board (I believe from memory were 4A/160V) were not blown.
    So being inexperienced, I am not exactly sure how to test the Voltage coming in to what I believe are transformers. There is also a connector (CN11) above the Large "CMO" label (all the way to the one side of the board) that hosts 2 wires. I have no idea what it is or if it could be some other influence that could be affecting the Backlight output not to occur. I believe CN11 Connection wires goes under the display metal encasement. The wires are not as thick as the other wires. I do not get any voltage reading from them as well.
    So in short I am trying to confirm if the Inverter Board is the problem or if I should dig further into the Tv to check out the TCon Board. The TCON board I know is at least connected to the main board from what I can see currently in the disassembly process.
    Could also someone confirm if, I know this may be a "duh" question, the Tv has to be connected to a (cable,antenna,computer) input source to have the inverter board to supply power to light the backlights.

    Any help is greatly appreciated,
    Chris
     
  2. PaulEE

    Member

    Dec 23, 2011
    423
    32
    Look! Huge paragraphs! Instant turn-off on a forum. Try starting with, "hey, this thing's broke, can you help?" :)

    Without reading much of any of the above, look for bulging filter capacitors in the main power supply. These love to go bad in Westinghouse (anythings) with LCDs...and in cheap electronics, in general. The reason I ignored all the other stuff is because - if these are bad, the whole monitor may or may not work, and if it does, not well. If those caps aren't preventing ripple - think of all the sad logic circuits!

    Check those first. Are they good to go?

    If you did that, then hmm...
     
Loading...