When the CPU locks up the blanking circuit is supposed to trip and turn off the solenoids and lamps. This circuit is far from fool proof and a crashed CPU can leave the blanking high and solenoids and lamps locked on. When the lamp column drivers lock on the 27R resistors on the driver board will get smoking hot to the point they burn open circuit or even desolder themselves off the board. The run hot normally, but if they literally smoking hot, it probable have a locked on column driver.

The blown solenoid fuse is typical too. Blanking fails to detect a locked up CPU, solenoids lock on, sol fuse blows, lamp drivers lock on, 27 ohm resistors burn. Fix the locked up CPU before diving down lamp column issues.

Kind of looks like a segment decoder issue to me. left side of the display schematic or BCD connector on MPU. It goes PIA -> encoded data out J5 -> into Master Display -> 4543 decode segments. Make sure MPU J5 does not have any broken solder joints.

OR maybe is digits getting enabled at the wrong time showing junk data?