Non - working CRT viewfinder - any experts out there?

[Salar Ghazi]

Hi,
I got a CRT viewfinder from the very first HD-Cam from Sony (HDC-100 from 1986), which I want to use with my XH-A1.
This viewfinder has no designation, but resembles the Betacam viewfinders. It was used as a secondary viewfinder for the HDC-100 (which had a HD viewfinder by default) but the CRT´s resolution (from Matsushita) is SD.
Funny BTW, this viewfinder was used vertically, like a periscope, I had do flip
the screen 90 degrees to use it on the hotshoe of my XH-A1.
Now, everything is prepared now, but I get the same "garbled" image through the composite input from the Canon or any other source:
The image looks "combed" or "hacked" with thick scan lines and is repeated several times along the horizontal axis, but is relatively steady on the vertical axis.
I fed the viewfinder with several formats, NTSC-SD and PAL-SD and also HD1080-50I, but I always get the SAME result!?
I have the circuit diagram and board layout, there are two boards in this viewfinder called VF-9 and VF24.
But I do not know, wether the signal of the cam was delivered in SD or HD to the viewfinder. Any ideas?
All the best,
Salar Ghazi