Adjustments - Panasonic KX-G8300 Service Manual And Technical Manual

KX-G8300
Local Ocillator Tuning Control Circuit (IC604, Q611)
The frequency of the local oscillator contained in MIC is adjusted using the tuning knob on the display
unit. The voltages of the tuning signals (fine tune, coarse tune) from the display unit are converted by an
adder circuit IC604 and transistor Q611, and a DC output of between about 3V and 22V is obtained.
The tuning control voltage is supplied to the tuning pin of the MIC and it is used to control the oscillator
frequency of the local oscillator in the MIC.
Tune Signal Rese
to MIC
Tune Fine =
Tune cena a
T 5V
Tuning Indicator Circuit
Part of the IF preamplifier output is sent to narrow band amplifier Q606 via T601. Q606's collector circuit
is connected to a 60 MHz tuned circuit (C626, T605). The IF signal from the tuned circuit are detected by
the diode detector circuit (D605, 606) and sent via Q607 to the display unit as the tuning indication signal.
When the IF signals have a frequency of 60 MHz, the output level of the tuning indicator reaches its peak
(approx. 2 VDC); when the frequency has shifted by about 2 MHz, the output voltage decreases to half
level. In the display unit, the tuning condition is indicated on the display on the basis of this voltage.
Reso
+12V
TUNE IND
R654
ADJUSTMENTS
General
Table 1 lists the adjustment Method required for the adjustments below which are to be performed in ad-
dition to the adjustments undertaken when the radar system is installed.
'These adjustments should be made when;
a. Major components have been replaced
b. An adjustment error is suspected to be the cause of trouble