Mechanical Adjustment; General Alignment Instruction; Record/Playback Head Azimuth Adjustment; Am If/Rf Alignment - Sharp GF-4646 Service Manual

Except for the following item, refer to the RD-620/A Service
Manual already issued.

RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT

n
As shown in Figure 5-1, make connection of instrument,
and adjust the head azimuth adjusting screw so that the
output signals from both channels will have maximum
waveform with the same phase in right and left.
Should it become necessary at any time to check the align-
ment of this receiver, proceed as follows;
1. Set the volume control (VR103) to maximum.
2. Attenuate the signals from the generator enough to swing
the most sensitive range of the output meter.
3. Use a non-metallic alignment tool.
4. Repeat adjustments to insure good results.
5. Set the Function Selector Switch (SW102) to "radio"
position.

AM IF/RF ALIGNMENT

l Set the signal generator to produce a signal of 400H2, 30%,
AM modulated.
For adjustments in steps 4, see [Note1 .
l
T E S T FRE- D I A L A D J U S T - REMARKS
IF (As shown in Figure 5-2, make connection of instruments.)
RF (As shown in Fiqure 5-3, make connection of instruments.)
Repeat steps 2.3.4 and 5 until no further improvement
bringing a piece of ferrite (such as a coil slug) near the antenna
loop stick, then a piece of brass. If ferrite increases output,
loop requires more inductance. If brass increases output, loop
requires less inductance. Change loop inductance by sliding the
bobbin toward the center of ferrite core to increase inductan-
ce, or away to decrease inductance.
I
HEAD
Figure 5-l
Figure 5-2
Figure 5-3