Viewsonic VX2718-PC-mhd SG2701B01-8

[StefanNg]

Hi, Badcaps.

I am troubleshooting a monitor
Viewsonic VX2718-PC-mhd.
Panel model SG2701BSG2701-8
Symptoms is no image.

This panel has 2 panel board connected by a U-ribbon.
When I disconnected the ribbon, I get a perfect half screen image.
I took some test point voltage, when ribbon disconnected.
HVAA 8.38v
FVDD12 1.21v
FDD33 3.3v
VIN 11.79v
VAA 16.85v
VGHF 30.16v
VGL -8.02v
CK1_I ~ CK8_I 1.403v
CK1_L ~ CK8_L 8.26v

When I connect both panel board
HVAA, VGHF, and CKx_L all dropped to 0v
VAA dropped to 1.094v

I want to trace where the short.
I need guidance and thank you in advance.

[StefanNg]

Updates

The U-ribbon supply clock signal from right panel board to the left panel board. I am able to get a full image after block clock signal using tape (STV, CKVs, VSS, LCs)

However, full image I get has some visible horizontal line, caused by some line is dimmer, refer photo.

Turning on the monitor, I measure CKV of the good side compared to the faulty side.
CKV voltage of the good side is stable at 8.2v, while the faulty side voltage is fluctuating from -0.5v to 2.5v (each line varies)

Is there any suggestions can improve image quality?
Is it safe if I connect/joint all the CKV test point on faulty side?
But I am interested to know what causing the CKV voltage fluctuating. I disconnected it from the U-ribbon, but it shows there is voltage.