Samsung UN65NU6950 edge lit TV LED bar after 10k usage hours

[howardc64]

Edge lit LED TV has 1/4 section backlight out. Replaced the LED bars and sharing the findings on the original 10k hour LED bar.

These are 6V LEDS (reads ~5.4+ on my LED tester) New bars read about 147V per 1/2 of each bar. Clearly original LED bar has some problems

• One section is 153v with a dead LED so clearly built up resistance
• One section flickers but magically fixed itself after driving individual LEDs. All done with an LED tester so don't know if would work driven by PSU backlight circuit and how long it would last
• Connector pin to test pad resistance is nearly 0 ohms. This is the highest current flow section on the bar since entire 1/2 of each bar's LED + and - are supplied through just 2 small solder point. 0 ohm indicate the connector solder joints don't have problem on this 2018-19 era TV with its lead free solder formulation. I've fixed many Apple Thunderbolt Displays LED bars in this exact section. 2000-2010+ era lead free solders had longevity problems (also fixed many similar era Car ECUs TCMs with same problem) In general, leaded solder handles thermal cycling and vibration much better than lead-free (gets brittle with cycling) I heard NASA only send lead soldered electronics into space

Hardest part of the whole repair effort was getting rid of the LED thermal tape stuck on the chassis. Its critical to have a clean new LED bar mounting surface for 2 reasons

• New LED bar thermal tape makes good contact for best thermal transfer
• Edge lit diffuser fits directly and tightly on top of the LEDs. No extra space. If New LED bar mounted on top of old thermal tape, probably difficult to reinstall edge lit diffuser.