You're missing other things... I would post a pic of the entire MPU. Multiple 40 pin ICs MPU/PIAs are missing in that pic. I'm assuming you didn't pull them or the missing interconnect pins?

See page 5 here for Tri-Zone IC details:

https://www.ipdb.org/files/2641/Basic_instruction_manual_Tri_Zone.pdf

You may be ok with 4,5 6,7 (according to THAT manual page at least).

Boards of that era sometimes had a single combo ROM at IC14, and sometimes multiple game ROM chips at the other locations of U26, U22, U21. It's not uncommon to see multiple variations for a single title. All depends on what was available at the time. U21,U22,U26 are earlier style masked ROM chips which were being phased out at the time, the combo EPROM at U14 is the preferred option.

-Hans

This is the correct set up for Tri Zone mpu with Bipolar Roms the pads should be filled at IC 26 and IC 14 (install a socket at 14) to allow a secure thru hole connection

Rom at IC 14 Use:

Remove J4 and connect J3

Remove Prom's at IC 22 and IC 21

Fill in solder pads at IC 26

Install socket at IC 14

Suggest replacing socket 17 and 20

Flipper rom set: if they cannot be tested replace roms 17 and 20 along with IC 14

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