LG Television - 42LG50-UA

[chrometsuba]

Hi Everyone,

Trying to diagnose a TV that does not power on. The crystal clocking the main application processor looks suspect to me, I have attached a pic of what my scope is detecting on the crystal pins.

This should be a 54mhz device, but obviously isn't running properly.

Before I order a replacement part, is there anything else I should check that might be causing this erratic clock signal?

Thanks

[tesla2020]

Re: LG Television - 42LG50-UA

If you have already checked that all the voltages at the source and they are fine also if you checked all the voltages of the dc-dc converters and voltage regulators of the main motherboard and they are fine then yes

[dick_barton]

Re: LG Television - 42LG50-UA

Using the oscilloscope to measure the crystal I much doubt would work since the scope probe capacitance and impedance will load the crystal.
You could look to see if any of the pins of the IC are clocking a decent waveform.