Its hard to tell from a picture since the LED's cycle, but in the manual checkout page C-50 which has a connection diagram for the LED boards. Since its one big serial chain you should see what the last board that is working and its probably the next GI board. From the picture could be board 20 or 21. You can skip a dead GI board which will bring the rest up but they won't have the correct colors. Just a way to verify it is that particular GI board.
Once you find out ping lloyd JJP will send you a new one super fast.

Yours looks like either board 16,17 or 18. You will have to look under the playfield and see. Like I said you can skip it if you don't have a replacement handy until one comes in. The colors may not match but its more playable than having no leds on half the PF

Yeah I'm on GI board number 6. four of them where board #16..put one of the new designs in so far so good.

You can figure it out by looking at page C-50 in the manual. This has a diagram of the serial LED board chain which has arrows directing you from board to board. If one of the boards dies in that chain...everything behind that board will be out. So I would look at that diagram and follow the working LEDs to the first board (which is likely a small GI board) that is not working. Once you find it that's probably your issue. You can skip that board by taking it out of the serial chain... so the output from the previous board would plug into the input (output is green input is red cable end) of the board after the failed one. Basically skip it...the rest of the playfield should come on. As I said the colors won't match but that will verify that board is dead and you can still play.

I would hope JJP would replace your GI boards with the new design. Assuming the small GI boards are the ones always dieing I would think JJP would take care of you. Shoot call Jack directly I bet you get what you need. Good luck I hope you get it dialed in.