64x64 ABCDE - black horizontal bar problem

[olablt]

Testing chain with 3 LED panels:

sudo ./clock -f ../fonts/10x20.bdf -d "%H:%M:%S" --led-brightness 50 --led-cols 64 --led-rows 64 --led-chain 3 -y 25 -x 50 --led-slowdown-gpio=4

Result:

I am using passive adapter https://github.com/hzeller/rpi-rgb-led-matrix/tree/master/adapter/passive-3 and modified as per instructions:

#360 (comment)

Back of my panels:

What could be the problem?

[Feuerflamme]

i have the same problem

[olablt]

soldered active board, problem gone