Tuesday, April 3, 2018

Trouble Shooting LA78040

IC LA7804X is a very popular vertical ic and can be found in various TV brands, this is already supports the bus control and can also work with single power supply and dual power supply, and the supporting components are not much so make it easier to repair in case of damage. Here's the LA78040 IC legs arrangement for single power supply:
  1. -in (This pin is connected to the control size circuit)
  2. Vcc (Power Supplay)
  3. Pum Up (connected to V-PROT circuit)
  4. Gnd
  5. Out (towards deflekksi)
  6. Vcc out
  7. + in VRAMP_OUT +

Chronology of damage:
  1. Vertical is not open or just a horizontal line
  2. Vertical Amp and Linearitation Defect Vertical, vertical can not be full top or down, vertical widen the top or bottom only, vertical shrinking the top or bottom only.

Handling:
  1. To handle a vertical that can not be opened first Please measure voltage on pin 2 is LA78040 if voltage drop / check check Elco C511, if Normal check voltage Pin no6 -> if Normal check VRAMP OUT, If Less checks D505, If all voltages Normal Check or replace Vertical IC LA78040.
  2. Vertical defects Amp and Linearity. Adjust Vertical Size. (data bus), if after adjusting can not normal, check R503, R515, R513, R514, R520 and C515. View this brought a picture.
Trouble Shooting LA78040
Trouble Shooting LA78040

Block Vertical LA7804X
Solution:
Replace broken parts with new components, before trying to turn on the tv check and make sure everything is installed, and not something that can cause a short.