LG 42PJ350N completely blown Y-SUS

[PowerAmpFreak]

WOW! Checked a "clicking LG" today and the Y-SUS was completely blown.
Nearly all power semiconductors had gone into heaven.
As a power electronics designer, I begin to wonder what these guys are doing in terms of "circuit protection". Common sense tells that a failure in one stage should be isolated and won't take other stages with it in the dark.
Appearently these guys are not paid to provide this kind of protection, probably module swap is the only solution these days.

[tom66]

Re: LG 42PJ350N completely blown Y-SUS

What semis failed? LG label them. If for example the SUS UP FET failed (connect output to VSUS) then the SUS DN could fail too... but the ER UP/DN and the RAMP UP/DN should survive, because they're rarely active and they don't have direct paths for the SUS voltage to go.

Quite a common problem is the firmware, which controls the FETs, can go bad or crash, causing an anomalous condition. Or, the firmware doesn't include any method for detecting a fault, leading it to continue to operate, damaging more stuff.

[Vesku]

Re: LG 42PJ350N completely blown Y-SUS

SYS_UP's and SYS_DN's shorted on my case. I can't find anything else wrong on the board with a quick look.

I ordered new FET's, but just wondering has anyone else had a go, did the FET's help or is there some underlying issue that causes the failure in the 1st place?