no picture(black screen) but has sound

Discussion in 'General Electronics Chat' started by Tetsu, Feb 4, 2005.

  1. Tetsu

    Thread Starter New Member

    Feb 4, 2005
    4
    0
    [attachmentid=383]hey guys, im hoping someone will be able to help me out. someone gave my neighbor a huge 32 inch (i think) tv its and rca (i heard bad things about rca but i still like them. well i tried the tv out and i heard it click on i was so happy but as time went by the picture never showed up but i could heard the static of the station( i didnt have any cable hooked up) i opened the tv up and looked around, i only seen one wire that wasn't connected it had a white thing at the end that looked like it pluged into something but i looked everywhere and could not find where it went. the wire is connected to a big round red copper looking wire in the shape of a cirlce which is located below the light tube or whatever its called. i checked the fuse and all that and didn't see any burn marks so if anyone can think of anything to why it is doing this please lemme know, i would really like to get it fixed if its not that expensive. thanks in advance

    Tetsu :ph34r:
     
  2. n9xv

    Senior Member

    Jan 18, 2005
    329
    1
    Hi,

    try hooking some type of antenna to it. Some sets have a video squelching circuit that makes the crt go "black" when no signal is present. The wire you described sounds like a grounding/degaussing ring but that wont keep the crt from lighting up. Other than that, sounds like a classic high voltage/sweep circuit problem. if you have a high voltage probe, check to see if you have any trons on the big wire going to the picture tube. - - - BE EXTREEMLY CARFULL! - - - there could be 15 to 35,000-Volts DC on this wire. Another way to detecting sweep output; hold a small transistor radio near the wire (6" to a foot should do) and you should hear a bunch of hash. Sounds like a dozen saw mills in operation at the same time. Anyway, its a starting point.
     
  3. Tetsu

    Thread Starter New Member

    Feb 4, 2005
    4
    0
    I tried plugging the Tv into a cable source but it still has that static sound and no picture. im only a beginner at Television electronics so i don't really know how to do voltage checks all to well. of this were my amp that went to my car i could probably fix it lol. anyways i was thinking of just sending it to a shop any idea how much something like this would cost to fix? :ph34r:
     
  4. n9xv

    Senior Member

    Jan 18, 2005
    329
    1
    Without knowing anything else about the set, it "should be" within $50.00. In any case a shop would probably diagnose it for $10.00 or so and then apply it to the actual repair bill if he proceeded to fix it.
     
  5. Tetsu

    Thread Starter New Member

    Feb 4, 2005
    4
    0
    Hey, i was looking over board and realized there was something missing i looked over this little piece of paper that explains what everything is and i found out that im missing a degauss thermistor in its place are 2 metal wires sticking straight up. if anyone could explain what this is and how i go about getting one please lemme know.
     
  6. mozikluv

    AAC Fanatic!

    Jan 22, 2004
    1,437
    1
    hi tetsu

    as what "n9xv" suggested, i second that recommendation. there's no point in getting yourself electrecuted just to save a few bucks. a tv is not an experimental set for beginners.

    as i also suspect base on your description the tv is having a high voltage shutdown or a defective picture tube or video if you have the presence of high voltge. :)

    that degaussing thermistor or coil operates in the low voltage power supply and has nothing to do with your tube not lighting up.

    the chassis # you mentioned are the early 90s models.

    have attached a schem on how that degaussing therm is connected.
     
Loading...