Hi,
My english is too bad to describe the whole process accurately
but shortly:
U15:
PAL16R4
pin1 - always Input, CLK function
Pin2-9 - always Input
Pin 11 - always Input, OE function
Pin 12,13,18,19 - Input or Combinatorial Output
Pin 14,15,16,17 - always Registered Output
The functions of pins 12,13,18,19 should be determined on the basis of the schematic.
In Dot Matrix controller this pins are Outputs (but can be feedback to logic matrix).
Three register cells are used as divider 2/4/8
Pin 15 (12 Mhz)
Pin 14 (N.C, but probably 6MHz)
Pin 17 (3MHz)
This signals are very likely feedback to logic matrix, that is why it is necessary to expand number of input combinations.
You can treat the 3.6/12MHZ outputs as extra inputs.
You have test all input combinations for 8 combination of 3/6/12MHz outputs.
I can prepare list of required input combinations.
In GAL16V8 you can configure pins12..19 as input, combinatorial output or registered output, information about pin type is coded in JEDEC file.
GAL16V8 can replace PAL16L8, PAL16R4, PAL16R6,PAL16R8
JEDEC file for GAL16V8 is other ten for PAL16R4 even both do the same (different fuse maps).
We will do it without the help of chinese company

As a last resort, you can send me these chip to reverse engeenering.
Regards,
up8051 aka JarekC.DIY