Elenco Electronics ST-751 Assembly Instructions Manual page 7

Nut
Cable Notch
Jack Notch
Install the label onto the case. Be careful to place the label on neatly
and correctly. Peel the backing off the expose the glue.
Place the PC board assembly into the case as shown in Figure 6. Use
two #4 screws to hold the case together. DO NOT OVER-TIGHTEN or
the holes may strip out. Tighten the nut down on the earphone jack.
Press the knob onto the gain control shaft.
This completes the assembly. Your unit is now ready for testing.
Jack
Screw
Figure 6
-6-
Label
Case Top
PC Board
Probe
Notch
Screw