JBL Soundbar 2.1 Deep Bass PSU No DC Power Output (Detailed, w/ Schematics)

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  • _AcE_
    Capt. AcEitor
    • Jul 2023
    • 3
    • South Africa

    #1

    JBL Soundbar 2.1 Deep Bass PSU No DC Power Output (Detailed, w/ Schematics)

    I have two of these soundbars, both with the exact same issue. The soundbars were hit by lightning and no longer power on. The PSU does not output any voltage on the DC side. When plugged into mains, the DC output is a stone-cold 0.0 volts. The AC side of the PSU seems to be functioning correctly (as far as I can tell). When checking the plugged-in PSU with my thermal camera, the OB5269CP PWM controller (U1) and the two resistors (R12 and R13) pulse on and off. These run to the positive DC side of the bridge rectifier (among other components along the way).

    There's no physical damage to the board or any of the components. I cannot for the life of me find any issues anywhere on the board. There are no shorts, no blown components/fuses, caps seem fine, resistors and diodes all seem to check out when testing with my multimeter.

    What I've tried replacing (made no difference, so I reinstalled the originals):
    • Replacing the bridge rectifier
    • Replacing the OB5269CP PWM controller
    Looking at pages 23 & 24 (Soundbar Power Board - CIRCUIT DIAGRAM) of the attached schematics, can we all agree that the DC output of the CON2 connector should be 23 volts, right? Push comes to shove, I'd then just replace the dead PSUs with another aftermarket 23-volt power supply with sufficient current ratings. CON2 is where the PSU then connects to the main board in the soundbar.

    I've attached high-res photos, videos, and thermals of the PSU, along with an attachment of the boardview/schematics. If anyone could point me in the right direction, any and all help would be appreciated.

    Full-Res Imgur Photos:
    Attached Files
  • CapLeaker
    Leaking Member
    • Dec 2014
    • 8324
    • Canada

    #2
    If that primary is pulsing, a very good chance there is a short on the secondary of the PSU or there is a short on one of the other boards that is / are connected has a short. There are 2 power supplies, one for the sound bar with 23VDC and another one for the Sub with 34VDC.

    Could be also there is something wrong with the feedback like the optocoupler, voltage reference or that zener.
    First you got to find out if there is indeed a short on the PSU secondary or on the other boards connected to it.
    Also look if the PFC is running on the primary of the PSU. No PFC = no high DC voltage output. Check the voltage on the main filter capacitor. If the PFC booster is working, you should see like 380VDC on the capacitor. What about the gate drive circuit?
    The bridge rectifier isn’t the problem. Also check the primary of the transformer… maybe it is open?

    The deep bass PSU is 34VDC. Makes me wonder if you are looking at the correct PSU?

    Your vid shows the soundbar psu. So something isn’t right.
    Last edited by CapLeaker; 08-10-2025, 11:30 AM.

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