LG 55EC930V power supply problem

[R_J]

Re: LG 55EC930V power supply problem

chassis ground for the relay coil

This is wrong, one side of the coil is connected to HOT ground, You need to use HOT ground to measure the coil voltage on this power supply, using cold ground is why you measured 170v
Your power supply is working according to your voltage readings (+12,+24 etc.) If the inrush relay is not clicking I suspect whoever opened it has damaged it. Check the coil resistance, it should be around 200~300Ω

[xmandarkx]

Re: LG 55EC930V power supply problem

after close inspection i seen the relay winding's are damaged/broken and getting 80Ω

would that be the cause for it not powering the screen up?

[xmandarkx]

Re: LG 55EC930V power supply problem

thanks for the help so far, i will get the relay replaced and see what happens next.

[R_J]

Re: LG 55EC930V power supply problem

80Ω might be ok, remove the relay and check it again. What is the number on the relay and what is its coil voltage?

[xmandarkx]

Re: LG 55EC930V power supply problem

this is the relay

https://uk.farnell.com/oeg-te-connec...10a/dp/1892000

i wont be able to remove the relay until i get to work tomorrow. hopefully i will have a replacement for it there too

[R_J]

Re: LG 55EC930V power supply problem

80Ω is too low for the coil resistance, it should be 267Ω, so if its not the coil it could be something else in the circuit causing the lower resistance
Relay# SDT-S-112DMR 12volt

[xmandarkx]

Re: LG 55EC930V power supply problem

the coil is definitely broken, i have an end and loose wires!
i will get it changed over and see what that does. if i dont have one at work ill get it ordered and will report back.

[xmandarkx]

Re: LG 55EC930V power supply problem

the relay has been replaced but the only thing its doing new is clicking when i power it on, still no screen coming on

[R_J]

Re: LG 55EC930V power supply problem

What do you mean clicking, when the tv is turned ON the relay should click ONCE. I don't think the problem is with the power supply, It is likely with the t-con, panel or main board
Have you checked the other threads for this model?

[xmandarkx]

Re: LG 55EC930V power supply problem

yeah it clicks once when the power button is pressed, and again when is turned off.

ive not checked the other threads as i was lead to believe it was just a power board fault.

can you recommend any threads that may help or should i just have a search?

[xmandarkx]

Re: LG 55EC930V power supply problem

ive just noticed a heatsink type thing on the main board and it is really hot to the touch, i think that may be the area i need to look at first

[R_J]

Re: LG 55EC930V power supply problem

OK that is normal, when the tv is turned ON the relay shorts out the inrush thermistor, thats all it does. When the tv is turned OFF the relay opens and the power supply goes to standby and only a small amount of current flows through the thermistor to maintain the standby voltage.
Check this thread:
https://www.badcaps.net/forum/showth...light=55EC930V
This thread has a service manual and a training manual on how to test things

[perrier]

Re: LG 55EC930V power supply problem

Hello, can you give me the references of the transistors Q151 and Q153 and the value of the resistor R174. Thanks in advance