Adjustment Procedures - Grundig Fine Arts M 100-A Servicehandbuch

Abgleichvorschriften / Adjustment Procedures
GB

Adjustment Procedures

1. Tuner (only M 100-R)
Test Equipment:
Sweep generator, Test generator, Stereo coder, AF-generator, Oscilloscope, Digital voltmeter, AF-Voltmeter, Distortion meter
Note:
Layout of adjustment controls see page 2 - 3.
The frontend is a completely preadjusted module. Only the IF filter must be adjusted to the IF amplifier (1).
The values of the tuning voltages are as follows:
87.5MHz = typ. 1.6V min 1.3V
108MHz = typ. 8.0V max 9V
Adjustment
1. IF Filter FM, 98MHz.
Sweep generator 98MHz to aerial socket. Level approx.
100µV / 75Ω.
Oscilloscope to testpoint B .
2. Demodulator FM, 98MHz
Test generator 98MHz to aerial socket. Level approx.
100µV / 75Ω, ∆f = ± 40kHz.
Distortion meter to AF output.
3. Field strength FM, 98MHz.
indication Test generator 98MHz, U
Digitalvoltmeter to testpoint F .
4. Station search FM, 98MHz.
Test generator 98MHz, U
Digitalvoltmeter to testpoint G .
5. Stereo Crosstalk FM
Stereocoder, left channel modulated, to aerial socket.
AF voltmeter to AF output, right channel.
6. Adjacent channel FM
AF generator 114kHz, approx. 100mV to the input of F2 D
filter
(Pin 2).
AF voltmeter to the output of F2 D
7. 38 kHz Filter FM
Test generator to aerial socket; FM, f
AF voltmeter to AF output.
8. 19 kHz Filter Test generator to aerial socket; FM, f
AF voltmeter to AF output.
9. MW Oscillator MW, 531kHz
Digitalvoltmeter to testpoint E .
10. MW RF Circuits MW
Test generator via 120-150µH parallel to frame aerial; AM,
U = 3µV, m = 30%, f
RF
AF voltmeter to AF output.
2. Amplifier
Test Equipment: Digital voltmeter
Adjustment
Quiescent current No Input Signal. Volume to minimum.
(Amplifier Board Turn on the set for at least 2 minutes.
left channel and
Amplifier Board Digital voltmeter between MP
right channel) or between MP
2 - 2
Preperation
= 300µV / 75Ω to aerial socket.
RF
= 100µV / 75Ω to aerial socket.
RF
D D D (Pin 4). D
= 38kHz.
mod
= 19kHz.
mod
= 1kHz.
mod
Preperation
a b
and MP
c d
and MP .
Adjustment Procedure
Adjust F1 a to maximum and symmetry.
Adjust F7 i to K
min
Adjust R119 F to 1.5V + 0.05V.
Adjust R123 S to 1.2V + 0.05V.
Adjust R69 C to minimum.
Control the left AF output with modulated right channel.
Adjust F2 D to minimum.
Adjust F9 J (left channel) and F11 K (right channel) to
minimum.
Adjust F9 G (left channel) and F11 H (right channel) to
minimum.
Adjust L18 to 1.1V.
VI
Adjust C3 and F6
IV
558kHz to maximum. Repeat the adjustment reciprocally,
end with 1449kHz.
Adjustment Procedure
Adjust with R109 for 9.4mV
,
M 100-A / M 100-R
(typ. 0.12%, max. 0.2%).
at 1449kHz and L1
VII III
±
0.5mV.
GRUNDIG Service
at