Try use WD utility from WD web site. Check it. If it not help then use WINHEX trial version and check if you can see hard drive like physicl device. Try use R-STUDIO program also . it may help restore data. In Case If your drive size “0” or it asking you reformat it then use some WD data recovery service like : www.datarecoverywesterndigital.com
For divorced, Corrupted or broken Apple Fusion Drive first of need use tools : R-Studio or UFS Explorer. It support it and can help very well. In some very difficult cases if it not help you then you can sent it to me . I will help.
I got my friend monitor LG 31MU97 with the same problem no power and LED light. I just use PIN point test use service manual for LG 31MU97. And i found what CPU stuck in boot loop with error report. So i just updated Firmware in ROM in IC205 (MX25L8006E) it have error checksum before. It is 1 Megabyte rom. And after update everything works again. I did it with two my friend monitors. It is common problem how i see.