BTW, another small discovery: in -SC model machines there's a converter board between the motherboard and the new LED display, it has a FPGA and a LED backlight driver on it. in the early reply of this topic, a friend seems like find that this board has another kind of signal, because he/she cannot use this FPGA board in older Tek scopes which using KCS057 balabala displays. but what I found is, the motherboard outputs the exact same signal, and the -SC model scopes can totaly use older 15pins KCS057 CCFL displays.
However, that FPGA board has some very strange behaviors: it won't work if u not connect the backlight power of the FPGA board, this board will just refuse to work, even sometimes turn it on without connetc that will cause some strange damage to the board. Also, this board seems like very fragile, my scope and other some selling broken -SC scopes have these kind of FPGA board, and display some very strange frames, some are like old crts lose their H-sync or V-sync. Dont know how to repair now.