Solved! Hisense 50K23DG blank screen

Jan 19, 2022
2
0
10
1
my Hisense 50k23dg has a black screen. It was working properly, but went black due to strain on the AC power cord. I pressed the AC cord into the connector on the back of the TV and it came back on for a while. But, after some time the problem occurred again. I repeated this process a few times but eventually it quit working. Now it won't power up.
I took the back off the cabinet to inspect the AC connector, expecting to find it loose or broken. That was not the case, it was solid and looked fine. I plugged the AC cord into the connector and checked for voltage at the pins where the Power Board connects to the AC connector. I have 120VAC at those pins. I tried to turn the TV on using the Power button on the side panel, but no response on the screen. I checked for DC voltage on several of the capacitors on the Power Board, but none anywhere. All components on the Power Board look fine, no evidence of failed components or arcing.
What to check next ?
 
Jan 19, 2022
2
0
10
1
After further troubleshooting I found that the solder connections where the AC plug connects to the Main Power board had issues. I could probe for AC power at the plug connector and sometimes there would be power beyond the solder connections and sometimes not. After looking closely at the solder joints I realized that there were hairline cracks in them. It took a magnifying glass to see them. I re-soldered both connections and retested a couple of times. Problem fixed !!
 
Jan 19, 2022
2
0
10
1
After further troubleshooting I found that the solder connections where the AC plug connects to the Main Power board had issues. I could probe for AC power at the plug connector and sometimes there would be power beyond the solder connections and sometimes not. After looking closely at the solder joints I realized that there were hairline cracks in them. It took a magnifying glass to see them. I re-soldered both connections and retested a couple of times. Problem fixed !!
 

ASK THE COMMUNITY