LEDS on the motherboard? I only find 4, not 5, MB or bad Display?

I was upgrading RAM to 16GB, upgraded to a new SSD, copied a;; over using CCC.Ran the new SSD on my own iMac and it works fine. After putting all back together ,on the bench iMac no display backlight or image. If I plug in my external SSD, the external operated like it is ok (the drive clicks and get to a stable place). So my thought is a bad monitor. Yes, I changed the cable, no I don't have an external to check with Attached the LED photos from MB. .All the 4 visible LEDs are lighted when power is on. Any ideas? This is not a retina display. One photo shows lighted, one is just board

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2.3GHz i5 (HDD) , 21.5" mid 2017 iMac18,1. EMC 2068 Model A1418. Motherboard 820-00629-A

Turns out there are only 4 LEDS on the MB, not 5. In this repair job, it was the video GPU that went out. New GPU and things working fine. Thanks to everyone who read this. Carl