how to reduce backlight volts/current JVC LT-49C550

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • jimbofz
    Badcaps Veteran
    • Apr 2013
    • 539
    • uk
    #1

    how to reduce backlight volts/current JVC LT-49C550

    This model had backlight strips replaced 6 months ago and reduced backlight from 10 to 5. You have guesses it, the customer despite my advice turned it back up to 10 so now backlights have failed.
    I have reapired the TV and checked the voltages feeding each strip and I would like to know how to reduce the voltage /current feeding the 2 backlight loops. The chip used on this UMC TV is 0cp8128 please see the enclosed picture of the data sheet.
    Attached Files
    Tags: None
    • jimbofz
      Badcaps Veteran
      • Apr 2013
      • 539
      • uk
      #2
      Re: how to reduce backlight volts/current JVC LT-49C550

      sorted
      i doubled the value of r14 and r9 reducing backlight current by 30% this should stop the leds from being driven flat out
      i still have acceptable pic even with menu set at 6 for b/l
      shame no one seemed interested

        Comment

        Previous template Next

        Related Topics

        Collapse
        • unimatrix93
          Which resistor should I remove/replace to decrease current to backlight leds?
          by unimatrix93
          Dear community, I want to increase the lifespan of my backlight led in my TV by decreasing the current.

          However I need some help identifying the resistor I need to replace to achieve this.

          Thank you!


          ​...
          11-29-2024, 05:05 AM
        • Document Archive
          Texas Instruments bq24745 bq24745RHDR bq24745RHDT Battery Charger IC for Laptop Computers Datasheet
          by Document Archive
          The bq24745 bq24745RHDR bq24745RHDT is a high-efficiency, synchronous battery charger with an integrated input-current comparator, offering low component count for space-constrained, multi-chemistry battery-charging applications. The input-current, charge-current, and charge-voltage DACs allow very high regulation accuracies that can be easily programmed by the system power-management microcontroller using the SMBus interface. The bq24745 charges two, three, or four series Li+ cells, and is available in a 28-pin, 5-mm x 5 mm QFN package.

          The bq24745 features dynamic power management...
          10-23-2024, 02:50 AM
        • Superbee_dad
          Sharp 80” long short flash backlight error - Help
          by Superbee_dad
          Hello Sharp TV experts
          Our Sharp LC-80LE642U displays one short one long flash error code which is a backlight error. I went into service mode and there were 8 lamp error counts recorded. I reset the count to 0 and did a reset. The last monitor error cause was 16 B00014639:12. 16 is the code for backlight error. I tried to power the tv up but went back into error mode.

          > I checked voltages on the power supply board and they all check out .. including 3.28 volts at the error pin.
          > There is power to the cpu and T-CONN and no faults found there. The cpu has a flashing...
          01-24-2025, 11:51 PM
        • DanPoka
          Guide me through repairing a Dell p2210f LCD ccfl backlight monitor
          by DanPoka
          I bought this p2210f dell monitor to fix. Schematic is the same as p2210.
          Behaviour is that monitors comes on but then backlight switches off almost instantly. If I look with flashlight I can still find the "No signal message". So definitely a backlight issue. Trying to advance the issue I proved that the protection circuit is switching off the backlight by shorting out C3 and resistor to disable the INL chip then re enable by removing the short.
          This is where it gets interesting. When I disassembled the monitor to solder leads on c3 capacitor I noticed the backlight flickered...
          02-15-2025, 05:05 AM
        • Mcfeetroy
          Fishing bite alarm drains battery
          by Mcfeetroy
          Good day to all. The bite alarm drains 9-volt Krona batteries. Current consumption when switched on is about 50 mA. I wiped the board from oxides, I will attach a photo (on the board there is a j3y transistor and a 7533 stabilizer, the microcircuit is erased = (the 3.3-volt stabilizer heats up weakly. I replaced it, nothing changed. I unsoldered the microcircuit, the consumption disappeared. The resistance on the pins of the unsoldered microcircuit from the point clockwise is more than 2 megaohms, the 11th leg is presumably ground. I warmed up the microcircuit, the consumption does not change....
          08-01-2025, 03:52 AM
        • Loading...
        • No more items.
        Working...