Apparently some units had an issue with the front panel locking up,
which this rev fixed.   I am using the earlier code, and have never
seen this problem.

V3.01 Lower EPROM checksum is 8470.   This is a 27C512 120 nSec EPROM.
V3.01 Upper EPROM checksum is 8269.   This is a 27C010A-12 or 27C1001-12 EPROM.

