I have a Williams Scorpion with missing digits, and the others not displaying the correct numbers. If I check the strobe lines for the displays, strobes 3, 5, 7, 9, 11, 13, and 15 are all stuck high in display test. Those strobes relate to the missing digits. I have checked them back to the mpu, with the 4J5 connector on and off of the master display, with the same results. I have also replaced IC18 the display pia on the mpu. I am guessing that IC6 the 74154 decoder chip on the mpu could be bad.

Am I on the right track or am I missing something?

I have reflowed the 40 pin connector, which looks in very good condition.

ABDED9E1-31CC-4C29-A685-5E59CEB740C6 (resized).jpeg

Thank You Pintec.

I will change IC10 and post back.

I changed U10 on the driver board, and the display issues are repaired.
Thanks Again Pintec.