In addition to this, the fuse on the SDB is supposed to protect the display, so check to see if it's blown.
Quoted from Quench:
RE: displays, what DC voltage do you measure at test points TP4 and TP2 on the solenoid drive board?
Note1: these are typically high voltages in the range of 180 - 240 volts so take care measuring.
Note2: you'll need to set your multi-meter to the 600V DC scale.