Adjustment Procedures - Grundig GDM5051 Serviceanleitung

Abgleichvorschriften / Adjustment Procedures

Adjustment Procedures

1. Tuner
Measuring Instruments: Signal generator, Sweep generator, Oscilloscope, Digital voltmeter.
Service works after replacing the FM tuner:
The FM tuner is a completely adjusted module.
Adjustment is not necessary.
Adjustment
1. AM IF Couple in a sweep signal of 450kHz to L110 (ferrite aerial)
via a loop aerial.
Oscilloscope to testpoint TP4 (IC102 Pin 18).
Band switch: MW
2. MW Oscillator MW, 522kHz
Digital Voltmeter to Testpoint TP3 (C104).
Band switch: MW
3. MW Aerial MW 588kHz, MW 1440kHz
bandpass Couple in a standard signal to L110 (ferrite aerial) via a
loop aerial, f
that the signal is just visible.
Oscilloscope to AF output.
Band switch: MW
4. 19kHz Filter FM 88MHz
Couple in a standard signal to aerial input (CN101A),
f = 19kHz.
mod
Oscilloscope to TP5 (left channel) and TP6 (right channel).
Band switch: FM
TC161
T163
2 - 4
Preparation
= 1kHz, m = 30%, U as low as possible, so
a
mod
CN101A
FE101
TP3
C104
IC102
T101
Pin18/TP4
Adjustment Process
Adjust to maximum with T101.
±
At 522kHz adjust to 1.7V 0.1V with T163.
Check: At 1611kHz <10V.
At 588kHz adjust to maximum with L110 (move MW aerial
coil).
At 1440kHz adjust to maximum with TC161.
Repeat this adjustment alternately.
Adjust to minimum with T103 (left channel) and T104
(right channel).
T104
T103
TP6 TP5
CDM 900
GRUNDIG Service