Hi i'm looking at a PANASONIC TX-L32C3B which won't turn on. It has a solid red light and will only flash in response to using the remote control. It is not giving any flash codes on it's own.
All voltages are present on the PSU board (5vsb and 16v) however i saw that the INV_SOS pin was high (3.3v). In addition, i also saw that the INV_ON signal was low (0v).
To try and prove that the PSU is not at fault, i injected 3.3v into INV_ON and found that the INV_SOS error disapeared (0v). Great! I had to also inject 3.3v into the INV_PWM input of the PSU too to make the backlight turn on, which it did. So this is looking like a mainboard fault. The mainboard is certainly not issuing INVERTOR_ON, but as i'm not that aware of the power sequence for this TV it might be because some other circuit has failed earlier in the chain.
The only problem is that the schematics i could find, use a slightly different main board and it's making things a right headache to try and follow. The mainboard number is TNP8EA112.
I've probed around as many rail voltages as i can find and compared them with a few similar schematics that i could download. It looks like i'm missing two voltages that should appear from a chip labelled bd81021.
Anyone had to repair one of these mainboards before?
All voltages are present on the PSU board (5vsb and 16v) however i saw that the INV_SOS pin was high (3.3v). In addition, i also saw that the INV_ON signal was low (0v).
To try and prove that the PSU is not at fault, i injected 3.3v into INV_ON and found that the INV_SOS error disapeared (0v). Great! I had to also inject 3.3v into the INV_PWM input of the PSU too to make the backlight turn on, which it did. So this is looking like a mainboard fault. The mainboard is certainly not issuing INVERTOR_ON, but as i'm not that aware of the power sequence for this TV it might be because some other circuit has failed earlier in the chain.
The only problem is that the schematics i could find, use a slightly different main board and it's making things a right headache to try and follow. The mainboard number is TNP8EA112.
I've probed around as many rail voltages as i can find and compared them with a few similar schematics that i could download. It looks like i'm missing two voltages that should appear from a chip labelled bd81021.
Anyone had to repair one of these mainboards before?
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