Philips 32PW6305/21 in standby -no CRT "gong"/RC/b

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Philips 32PW6305/21 3years

Hi,
when switching to EXT1, TV went to standby, red power button.

Sound works.
Standby LED lights red when mains button powered on.

No response from IR nor channel selection button on top.
No classic power on CRT "gong" sound.
TV is black.
Power to "main motherboard" is ok (but not sure of what voltage).

Does anyone have an idea of what may be wrong?

IR preamp?
Transistor to power unit?
Painter IC?
Driver transistor?

Thanks