Martel Electronics 235 - Manual (Page 82)

Fuse Replacement
Should it become necessary to change a fuse, take the following steps:
1.
Turn the calibrator OFF.
2.
Remove the 4 screws located at the corners on the bottom of the
unit.
3.
Raise the cover at the top of the calibrator (end with the display)
until it clears the power supply and LCD display and then move
the entire top towards the bottom about 1-2 inches. This will
allow you to reach inside with your fingers and disconnect the
keypad tail from the printed circuit card.
4.
Determine the blown fuse from the table below and extract the
fuse using a small screwdriver or paper clip. All input/output
fuses are located in the area of the input/output jacks, while the
two main power fuses are located in the area of the battery
charger jack. See page 80 for diagrams of the fuse areas.
Service Information
230/235 77
Read the following procedure fully and carefully before opening
the case for fuse replacement. Damage to the keypad and/or
keypad connector can occur if you do not follow these instructions.