Repairing (again....) lg 32'' LCD tv

[fezder]

Hey guys, figured id ask before i do anything stupid. So, i got this bigger TV, (LG 32LP1RS to be precise) which symptoms seems to be capacitor-based, as it needs to run couple of minutes, before it actually can be turned on. During this period, nothing happens when on/off switch is pressed, not even control signal comes to connector pins when pressed.

No caps are bulged or anything, esr's are in order and such. Of course, they can be leaking, and no surprise, they are chinese SAMXON brand, which is not-the-best, right? and they are right next to heatsink....

after checking service manual, i found out that specific ic, namely KIA7045, is in cooperation with on/off signal, and manual says to test kia's voltage. now this is where it gets interesting, system lets me probe and measure input/vcc side of kia just fine, but when i measure output, tv shuts off. However, when i take dmm/scope probe out of system, it starts again by itself. This confuses me, how come this happens?

any help appreciated, i plan to replace those second-grade caps with better ones, but what do you think? i can post photos if needed

 

[Nigel Goodwin]

That IC isn't a 'regulator', it's a voltage detector, so there's no 'input' and 'output' as such, there's a Vcc pin, gnd, and an 'output' which sinks current to ground.

It's generally used for a 'battery low' indicator, or resetting a CPU.

 

[fezder]

oops, my bad, thanks for correcting

 

[fezder]

Ok, little positive update, i replaced almost all caps from psu board, and it works now.

only 'lytics i didn't touch werew hv-caps.