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LCD Screen-black spots

Discussion in 'Electronic Repair' started by Dave_s, Apr 14, 2005.

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  1. Dave_s

    Dave_s Guest

    My 440 Handy Talkee [HT], a Realistic HTX-404, has been sitting without
    operating for 6 months. Now, the LCD display has a cluster of black
    shapes centered vetically and in 3/8 inch from left edge even when the
    HT is off or on. How can I makes these unwanted shapes go away?
    Appreciate any hints. Thanks, Dave_s, 73, W6MIK.
  2. Put sticky tape over the bits that should be there.
  3. Put sticky tape over the bits that should be there.
  4. Guest

    Replaced the damaged lcd display.
  5. Edd Whatley

    Edd Whatley Guest

    Now Dave, are you ‘rat sure that those are positioned “vetically” ? No
    by my being blind to your
    situation , e.g., not having the unit in hand for an eyeball QSO, coul
    you confirm that that
    condition is maintained even when there is no power or batteries in th
    (And even that thought process could be flawed in the respect o
    retentive charge in the ua
    current levels and low voltage levels still being maintained b
    capacitive elements in the radio
    for some time period after unpowering…..still adequate to effect
    display action)
    Also, was there any possibility of errant electrolyte seepage fro
    defunt batteries involved.
    My thinking would lean towards a contamination of a string of pixe
    elements in the LCD array
    to cause that effect. Or, my most common finding is a loss o
    connectivity thru a connector to
    the array.
    This can usually be confirmed by powering up the display and enacting
    moderate pressure to
    the x-y planes of the displays front bezel assembly, hoping that wil
    transfer enough movement
    to the internal connector area to cause a corrective action in portion
    of the display, thus tipping
    you off as to a display connection being the problem. Don’t..rpt…DON’
    exert pressure to
    the threshold of fracturing your displays glass front face, however.
    Also there might be the possibility of pressing on the rear of th
    displays contact area via an
    orange stick, wood dowel, etc., if access was obtained to inside th
    receiver housing after a partial
    disassembly. Should you find a corrective manner by pixels changing i
    that prior probing procedure,
    the most common cause of that condition is the manner of constructio
    and the specific materiel
    utilized in interfacing to the display. If you stored that unit in
    heated environment (sun ravaged
    car or storage building, etc)… is also more abject to failure
    Should this exploratory action have
    changed the display, get back to me and I’ll update you on what
    usually find that fixes the situation.
    73’s de Ed
  6. Dave_s

    Dave_s Guest

    I checked the HTX-404 this morning and found following wrong.
    1. BNC connector is mechanically loose but electrically OK.
    2. TX output is 0.5 watt in Hi PWR mode with 13.8volts power.
    Draws .2 Amps [3.6 watts] to create 0.5 watts RF out.
    3. LCD display has spots but can read most of screen.

    4. 12 hours storage disconnected from BP did not change spots.
    Pressing LDC display glass/bezel did not change spots.
    I did not open case and apply pressure
    to LCD connector area from back of radio.

    I am not going to put the money/labor into repairing this radio.
    It's future use will only be as a receiving scanner.

    Thanks for reply and diagnostic suggestions Edd,

    73, W6MIK, Dave
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