3 Internal display black, external workings fine but...
*
iMac working on external display
- problem
- Inbuilt display not working .
- There are only 3led physically present on motherboard No.4 which is mentioned in attached image start with iMac start but turn off automatically after few seconds.(after removal of lcd screen)
- but still external display working fine.
- Very very light display appear sometimes.
confused
- inverter problem?
- lcd to inverter cable problem?
- backlight problem?.
1.1千 
2.6千 
likely you snapped some cable while disassembly. Carefully disassemble and check everything.
> Mac hdd show multiple error message while OS X installation.
Next this happens, use something like http://www.system-rescue-cd.org/ ISO on a USB stick to verify and check HDD/SSD. command: smartctl
Just do not disassemble immediately.
bmx2019 さんによる
- Everything I solved successfully .
- No cable snapped checked twice
- Now facing Only 1 problem screen problem (very light display)
- I know it is inverter or lvds cable or back light or in same cases vertical synchronise cable problem.
- Need help how to diagnosis one by one?
Kailash Kamble さんによる