Question about Revell Control Board

[magcalus]

I am trying to upgrade an unused RC car from Revell with a raspberry pi. For radio rx, servo and motor control, it has a proprietary pcb from revell (revell 46722). I want to replace the radio control with signals from a raspberry pi.
With an oscilloscope, I found some PWM like signals, but have trouble understanding them. I probed the IC U11 the marked pins (green and yellow):

With these signals:

The period of the green signal is around 1.8kHz, the length of the green signal around 100us.
Neither the yellow nor the green signal change when using the remote control. The servo is moving though.

Does anyone know how to hack this board?

Cheers!

 

[STONER RC]

Oh man only one I know to answer that one hasn't been around.. I wouldn't even know where to begin with that one bud sorry.