I have a TCL 55P6US with sound and backlight but no picture. This model does not have a T-CON board, and the right (rear perspective) panel board is fed from the left panel board. I have not been able to induce any change by disconnecting the secondary panel board or the tape cut-off method on the primary board.
There are a bunch of voltages missing on the panel boards. I can't find any shorted caps of the panel boards, and all of the missing voltage rails read in the kiloohms, which leads me to suspect the issue may lie on the circuit board, rather than a short in the panel.
Below are test point readings:
I've been using this site as a reference https://pcbartists.com/design/power-...matic-tft-lcd/ (please suggest a better resource if you know of one).
I can't find a test point for VGH, but VGHF is not getting boosted at all from 12V VIN. And VGL is obviously missing too.
There is no rail labelled AVDD on this board. Is that the same as VAA? If so, I have no idea why HVAA is negative.
I think chip U2 (photo #4) is what is responsible for generating these voltages. It's labelled 17500G 2510S, but I can't find any datasheet for it.
The main BGA chip is labelled CSQ13-C4N K6952 1801-AB. It gets quite hot, but it came with thermal pads on both the top and bottom of the board, so I am not sure if this temperature is abnormal. The RST signal next to the BGA is stuck at 3.25V, which I find somewhat concerning. The other side of the resistors driving this signal (LOCKN and HTPDN) read Low, so it seems RST is being pulled High from the chip itself.
Does anyone have any ideas? I really don't know much about these panel boards, but I'd love to learn more. There are so few resources available though.
There are a bunch of voltages missing on the panel boards. I can't find any shorted caps of the panel boards, and all of the missing voltage rails read in the kiloohms, which leads me to suspect the issue may lie on the circuit board, rather than a short in the panel.
Below are test point readings:
| VIN | 11.90V |
| VDD33 | 3.29V |
| VDDD12 | 1.24V |
| VDD18 | 1.80V |
| VGHF | 11.67V |
| VGL | 0.19V |
| VAA | 1.07V |
| HVAA | -0.17V |
| VSS | 0.57V |
| VREF | 1.07V |
| VCOM | 0V |
| RST | 3.25V |
| SPI_EN | 3.25V |
I can't find a test point for VGH, but VGHF is not getting boosted at all from 12V VIN. And VGL is obviously missing too.
There is no rail labelled AVDD on this board. Is that the same as VAA? If so, I have no idea why HVAA is negative.
I think chip U2 (photo #4) is what is responsible for generating these voltages. It's labelled 17500G 2510S, but I can't find any datasheet for it.
The main BGA chip is labelled CSQ13-C4N K6952 1801-AB. It gets quite hot, but it came with thermal pads on both the top and bottom of the board, so I am not sure if this temperature is abnormal. The RST signal next to the BGA is stuck at 3.25V, which I find somewhat concerning. The other side of the resistors driving this signal (LOCKN and HTPDN) read Low, so it seems RST is being pulled High from the chip itself.
Does anyone have any ideas? I really don't know much about these panel boards, but I'd love to learn more. There are so few resources available though.
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