LG DIGITAL BUS CHASSIS. NO PICTURE. NO SOUND . NO STANDBY LIGHT [LG DIGITAL BUS CHASSIS TVs. [USED ICs- 5W973CD0 & LA76810]

The fault is with power supply regualtor section.

The power supply section of this TV, is transistorised SMPS,
Possible cause of power supply failure.

[1] Main rectifier diodes [shorted].  If rectifer diode has been shorted, it will blow up the fuse too.  so if the fuse is found opened, check these diodes first.

]2] PTC short.  If positive thermistor connected to degaussing coil shorted, the fuse will blow up.

[3] C902 & C901 [disc ceramic capaitors connected in parellel with two main rectifier diodes] short.  the fuse will blow up.

[4] Q904 [D2498]; main switching power transitor short [collector to emitter].  fuse will blow up.

[5] C821 [2K7 PF 2KV] connected to main ground and SMPS ground short. Fuse will blo up]

If blown up fuse noted, never insert an other fuse, until the fault has been detected and rectified.
When SMPS supply section is under suspection, check this section only after isolated it from the rest of the circuit. Replace all the transistors [both small signal transisors*3 and switching power tranistor] at the same time.  If C906 [47MFD] electrolytic capacitor connected to the base of the main switching power transistor is faulty, the power regulation to the SMPS will be poor, resulting low or high voltages at the output. Repalce this capacitor and D912(9V Zener diode) too.

Check the resistance value of [R917-39 Ohms 5W] & Capacitiance value of [C917-2K2Pf 2Kv].  If any one among these two components have any fault, the power sitecing transistor will blow OFF as soon as you switch ON it.

The two voltage outputs from this power supply section are 110VDC  and 20VDC.