Proms are both ST M27C1001-70F1
128k x 8, 70 nS, UV Erase

Low PROM Label
----------------------------
4031 100 53270
PM6681 REV15
L              V1.09
----------------------------

High PROM Label
----------------------------
4031 100 53270
PM6681H REV15
H                V1.09
----------------------------
