Repair of an LG split AC system indoor unit PCB

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • ngml
    New Member
    • Aug 2020
    • 4
    • Belgium
    #1

    Repair of an LG split AC system indoor unit PCB

    I am trying to repair an LG split AC indoor unit, which does not start and gives a CH05 error code.
    This indicates an error in the communication between the outdoor and the indoor unit.
    The outdoor unit is fine, so the problem is the indoor PCB.
    The indoor unit is an LG PC09SQ NSJ (3SNM09JA2FA), and the PCB has the following type number: EAX35907219-1.2 (see photo1)
    I changed optocouplers ICO1X & ICO2X and the NPN transistor S9013 which drives optocoupler ICO2X (see photo2), but this did not remedy the fault.

    Does anybody have the schematics of this board, and is willing to share?

    Any other input/advise regarding troubleshooting, is also much appreciated.

    Thanks in advance


    2 Photos
    Tags: None
    Previous template Next

    Related Topics

    Collapse
    • salah11
      No Ringer Sound in Intercom outdoor panel (Voice Communication Works)
      by salah11
      Hello everyone,
      I have a persistent issue with a commercial intercom system (likely made in Turkey, based on the unit). Voice communication (audio) works perfectly, but the outdoor panel did not return the ring when the call button is pressed.
      Whell the system consists of three main circuit boards (see attached photos):
      A. Board 1: Power Supply / Ringer Generator (White Board) with LS1240A, BD442 and BD140 Power transistors for ring amplification.
      B. Board 2: Handset (Indoor Unit) Role: Contains the microphone, the speaker/baffle, the manual hook switch, and the open-door...
      11-21-2025, 01:08 PM
    • domix
      LG Air Conditioner AC unit bypass
      by domix
      Hello,
      i have Lg AC indoor unit connected to heatpump warm water. To flow thru unit. I have it to heating up garage. I have previus old indoor ac unit. It was only connected to power supply and is was woking.

      Now i have new one which has a problem, it needs outdoor unit. It has error, 5 blinks which means that outdoor unit is not connected.

      how can i bypass this :/

      I need only to turn on and i need only fan to blow, and adjust speed od fan. To blow over a warm pipes....
      2 Photos
      11-25-2025, 02:54 PM
    • Gjackson
      Understanding air conditioner PSU logic
      by Gjackson
      Hi all,

      I have an air conditioner outdoor control board that I'm trying to understand how it functions. In short, the board takes in 240VAC and splits it into 4 other wires, 2 of these go to power the indoor unit and another 2 go to power the outdoor unit module board. the 310VDC capacitor bank on the outdoor control board get charged up from a rectifier on the outdoor module board. Now what I can't wrap my mind around is the fact that there is a relay in between the 2 mains wires that go from the outdoor control board to the outdoor module board which is normally open, what this...
      11-25-2022, 10:45 AM
    • dicky96
      Air Con PCB repair : some general question
      by dicky96
      Hi guys
      I've been getting more air con controller boards of various brands for repair - mainly the ones from the outdoor compressor unit and I realise I have a lot of gaps in my specific knowledge, while being pretty good at electronic repair in general.

      Does anyone know of any good resources for information on this sort of repair? I'm hoping here there will be some guys who are experienced in this. I'd specifically like more info on how the controller PCB works, because I expect they are all pretty much the same, and especially how it communicates with the indoor unit (protocols,...
      11-22-2024, 04:40 AM
    • otoluk
      Auriol weather station humidity sensor
      by otoluk
      I have two Lidl LD6273 Auriol units with DCF77 radio for time update.
      I really like the idea but the cheap moisture sensor(guess HR202L) inaccuracies make the device unreliable. Also not clear why indoor and outdoor unit sensors being same type doesn't match. For example I place both units on same table and indoor unit shows 23% humidity while outdoor sensor shows 39%. What I found out is that I get better readings if cleaning the solder points of sensor inside with isopropyl alcohol.
      Looking for replacement sensor which I could solder in place of HR202L resistive sensor but need...
      1 Photo
      11-06-2024, 07:57 AM
    • Loading...
    • No more items.
    Working...