I’ve stumble upon a fairly common appliance, present in most home, built by million of unit, a TV.
This model is a GRUNDIG 40VLE5324BG with LED backlight: not starting anymore (one could see the “Grunding” logo or “signal not present” when flashing a strong light on it).
After seeking the net for a solution, removing dozen of screws, accessing the 100cm long LCD panel made of ultra thin glass with COG and flex PCB on side, I finally had access to the culprit: No, it was not the capacitor, not the LED driver, not even a LED but a single connector: PCB to PCB connector, designed to decrease assembly time and cost. As these LED string are serial driven (140V @ 400mA), a single failure will render the whole system useless.
![](http://www.dotmana.com/weblog/wp-content/uploads/40VLE5324BG_led_failure-1024x782.png)
Just wiggling the connector would start/stop the backlight:
![](http://www.dotmana.com/weblog/wp-content/uploads/Peek-2020-04-20-09-55.gif)
In this case, slight flex, oxidation or poor connector plating cause the problem, and as the LED as serial connected, the connector is oxidized from long arcing:
![](http://www.dotmana.com/weblog/wp-content/uploads/20200419_155508-768x1024.jpg)
And the connector:
Let’s strap these connector with a piece of wire and fix this stuff!
Cheap 5ct clip will render a 500€/USD TV after few years! Hurray to planned obsolescence and global grow and economy!