Radio Shack 120-2130A - Manual (Page 9)

3. Position the stereo in the dashboard as follows:
a. Place one supplied nut and washer on each shaft and tighten the
nuts about halfway up the shafts.
b. From behind the mounting surface, insert the shafts through the
mounting surface.
c. Adjust the nuts on the shafts until the stereo's front panel lines
up properly with the dashboard. Insert the supplied gasket if
additional front panel support is needed.
d. Place another supplied nut and washer on each shaft and tighten the
nuts to secure the stereo against the dashboard.
4. Place the trim plate and shaft-spacing adapters over the shafts.
Select the shaft-spacing adapters that fit over the shafts and into
the cutouts in the trim plate.
5. Place the remaining washers and nuts on the shafts and tighten the
nuts against the shaft-spacing adapters.
Note: To further secure the stereo, if your vehicle's dashboard space
permits access to the back of your stereo, attach one end of the
metal strap to the bolt on the back of the stereo. Then attach
the other end of the strap to a solid metal part of the vehicle
using an existing bolt or the supplied self-taping screw. This
strap also ensures that the stereo is properly grounded.
6. Place the inner and outer knobs on the shafts.
7. Reconnect the wire harness and antenna.
8. Reconnect your vehicle's negative (-) battery cable.
Using The Line Level Components
This stereo has preamp outputs (phono connectors) for low-noise connection
to an optional equalizer/booster, power amplifier, or other device that
has line-level inputs.
To ensure a low-noise connection, connect a ground wire between the stereo
and any additional component.
Note: When connecting an equalizer/booster not sold by RadioShack, refer