On Wednesday, March 3, 2021 at 10:28:20 AM UTC-5, Stu jaxon wrote:
Hi Group, can someone help please, I replaced the main board 3655-0342-0150(41)... on a Vizio M550SV, the hdmi ports do not work. I resoldered the pins, and followed the suggestions in coppell tv repair video for a short did not find one,,,.. https://www.youtube.com/watch?v=8U-01HUx0qY. any help in this matter will be taken seriously, Thanks,

Your replacement board is bad..

There are *two* HDMI problems on that Am-Tran main: the first is a bad HDMI transceiver chip. If the TV catches some lightning back through the cable box, the HDMI chip will die. If the chip gets hot to the back of a finger within 15 seconds or so it's bad. The second problem is that the ball grid chip under the heatsink is either bad or needs a reflow. Reflows last 1-3 years by my estimation before the problem returns, and assuming of course you don't toast the BGA while reflowing it.