If the display of the 1038/16 Call Module is dead -
First check for 24V DC between 0V and +V of the MP1 terminal block.
Measure on the top of the pins that can be seen through the green connector block, and not on the screw heads.
If there is no 24V DC present then check for 24V DC from the 1038/20 Power Supply.
Note that there may be more than one 1038/20 Power Supply, and so make sure you are checking the unit that is connected to the 1038/16 Call Module in question.
Next try adjusting the contrast control (11) on the rear of the 1038/16 module -
If 24V DC is present between 0V and +V on the MP1 connector block and the contrast control makes no difference, then the 1038/16 Call Module should be replaced.
Please see the document below for a guide on how to replace the Digivoice 1038/16 Call Module