Re: LG 50PZ550 plasma help with diagnostics

Thanks for all of the help. I tried reflowing the main BGA chip using the recommended flux, temp sensor, and tried to follow one of the reflow curves that came with the flux (one of the higher ones that maxed out at about 245C), and at first I thought I had been victorious ... TV booted up properly 9 times in a row, but on the 10th attempt it was back to its old tricks. Took out the main board again, slathered it with a thick line of flux around all 4 sides of the BGA, and reflowed even hotter and longer ... figured I had nothing to lose....

Re: LG 50PZ550 plasma help with diagnostics

My flux and thermometer should arrive soon. What temperature should I try to maintain during the 3.5 minutes of reflow? Obviously it should be above 218 C but how much above? Wikipedia mentions "20-40 degrees C above liquidius". Perhaps I should try to maintain ~250 C? [url]https://en.wikipedia.org/wiki/Reflow_soldering[/url]Re: LG 50PZ550 plasma help with diag...hould be above

Re: LG 50PZ550 plasma help with diagnostics

OK thanks. I guess I will invest the $30 USD for the temp probe plus the recommended flux (I have an ancient tube from Radio Shack that predates the invention of SMD I think), and that temp probe looks like it could come in handy in the future. Thanks also to tvtimmy for your reply. I will let you all know how it goes once I have the equipment. Looks like that temp probe has a long lead time right now from Amazon.

Re: LG 50PZ550 plasma help with diagnostics



Hi, thanks much for the reply! Thanks for advice on pre-heating the whole board.

3.5 minutes? sounds like a long time but I have little to lose since I'm ready to toss this TV if I kill it. To be clear, I don't have actual SMD solder equipment ... I am using a heat gun designed for stripping paint, etc. I wonder if its way hotter than proper SMD rework equipment? Looks like my heat gun offers 750 degrees F and 1100 degrees F (400/600 C)...

Re: New Members - please post your introductions here

I guess I should be sociable and introduce myself. My immediate goal is to give a shot at repairing my flaky old Plasma TV before I junk it. Mixed emotions, as I hate to junk a TV that cost a fortune back in the day ... yet I could replace it with a nice 4K TV for only a few hundred bucks.

I am a life-long electronics tinkerer though my professional background is more on the software/system architect side of engineering. I am involved in research, design, and productization of "enterprise" electronics...

Re: LG 50PZ550 plasma help with diagnostics



Thanks for the reply! The problem my TV has is that sometimes when I press the "power" button on the remote or the power button on the TV itself (which is a capsense button), I hear a click but the screen never turns on AND the Red "standby" light on the front never turns off. I do see the screen turn a little "milky" and I see a faint ghost image of whatever was there before it went to standby, but the screen doesn't light up. When it gets in this mode, pressing the power button again does...

Re: LG 50PZ550 plasma help with diagnostics

Sorry if this is the wrong place to post this (just joined), but can anyone point me to a list of the error codes indicated by the flash pattern of the green LED on the logic board for this TV? (LG 50PZ550)