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11ak30 chassis

Discussion in 'Electronic Repair' started by b, Sep 26, 2006.

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  1. b

    b Guest

    Hi there,

    vestel 11ak30 tv.
    here's the story so far...set had a shorted HOT (would not come out of
    standby, if keys pressed set just chirped and red led stayed on). Set
    powered up fine without HOT in place. Connecting bulb across c-e showed
    b+ OK. No obvious solder problems, just resoldered one or two slightly
    suspect joints.

    Now for the annoying bit: Replaced BU808DFI HOT and c618 (according to
    schematic,7n2). New transistor blows out immediately. Now suspecting
    LOPTX shorted internally, before I replace it though, has anyone seen
    this problem before on this chassis?

    best regards,
    Ben
     
  2. b

    b Guest

    b ha escrito:
    For the record:
    replaced HOT BU808DFI, and LOPTX (HR 7950), also 10uF 63v horiz drive
    cap and 8n2 cap across HOT. Set now works.

    -B.
     
  3. jonhyr19

    jonhyr19 Guest

     
  4. jonhyr19

    jonhyr19 Guest


    hi I am newby in tv repair, sory for stupid questions, what did you
    meen when you say HOT?
    and when you say : cap and 8n2 cap across HOT.

    Thanks....


    jonhyr19
     
  5. jonhyr19

    jonhyr19 Guest


    hi I am newby in tv repair, sory for stupid questions, what did you
    meen when you say HOT?
    and when you say : cap and 8n2 cap across HOT.

    Thanks....


    jonhyr19
     
  6. b

    b Guest

    jonhyr19 ha escrito:
    no need to apologize. if everyone simply asked for information or help
    whenever they didn't know or weren't sure about things, the world would
    be a better place!

    Thr HOT= HORIZONTAL OUTPUT TRANSISTOR aka LINE OUTPUT TRANSISTOR.
    CAP= capacitor, in this case i changed two. One electrolytic type in
    the horizontal drive circuit (apparently prone to failure on this
    chassis) and also another polyester film type, value 8n2 , connecetd
    c-e across the aforementioned HOT transistor.
    see

    http://www.interq.or.jp/japan/se-inoue/e_capa.htm

    and
    www.repairfaq.org
    tv troubleshooting section.

    going back to the above parts, I usually test or change these parts
    first of all in any set with shorts or other problems in the horizontal
    stage, before moving on to the more expensive transformer. They suffer
    a lot in use and are generally (relatively) cheap and easy to get hold
    of.

    hope this helps.
    -B.
     
  7. jonhyr19

    jonhyr19 Guest


    Hi again

    I have two tvs with problems one with 11ak30 and 11ak30-1

    on 11ak30-1 i replaced HOT BU808DFI, and LOPTX (HR 7950), and all ok
    problem resolved

    on 11ak30, nothing apend, the aparent problem, the tv stay on standby
    and the red light flash, and a sound with the flash, if you toutch in
    any boton the light pass to green and again in red, and noting apend.

    HOT BU808DFI, and LOPTX (HR 7950) are ok, what seems to be the
    problem?

    jonhyr19
     
  8. b

    b Guest

    jonhyr19 ha escrito:
    sounds like there is something shutting down the power supply.
    first, check the voltage on the HOT. unsolder the HOT and connect a
    60-100 watt bulb across c-e terminals.switch the set out of standby to
    ON, see if the bulb lights and is steady.

    -Set your voltmeter to DC and put the red probe on the c, black to e.
    measure the voltage (should be between 115 and 130v depending on size
    of screen). try replacing the 160v capacitors in the b+ line from the
    power supply if it is not.These sometimes fail causing this problem.

    -try also unsoldering the outputs from the line transformer, and power
    supply transformer one by one to see if there is one shorted bringing
    down the power supply. (vertical, RGB, etc etc.)

    note that these are all very general tests, see www.repaifaq.org for
    more details. it's a bit hard to be more specific over the internet,
    without seeing the TV set!

    regards,
    B.
     
  9. jonhyr19

    jonhyr19 Guest

    When i put the bull in c and e something in HOT die and the light of
    standby desapear..

    jonhyr19
     
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