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Abgleichvorschriften / Adjustment Procedures
Adjustment Procedures
GB
1. Main Board
Test equipment: DC Voltmeter, Test Generator, AF Voltmeter, Stereo Coder
After repairing the RF or IF Part the adjustment of Signal Level Offset (para 8) must be done.
Adjustment
1. Oscillator (AM and
FM;
FM)
Connect a DC Voltmeter to FMP16.
2. AM IF
Connect a Test Generator to aerial input; LW; Frequency
153 kHz; no modulation; E´ = 50µV (34dBµV).
Connect a DC Voltmeter to FMP108.
3. FM Pre Stage
Connect a Test Generator to aerial input; Frequency
88.0MHz; no modulation; E´ = 3µV (10dBµV).
Connect a DC Voltmeter to FMP108.
4. FM Band Pass
Connect a Test Generator to aerial input; Frequency
88.0MHz; no modulation; E´ = 3µV (10dBµV).
Connect a DC Voltmeter to FMP108.
5. FM IF
Connect a Test Generator to aerial input; Frequency
88.0MHz; no modulation; E´ = 3µV (10dBµV).
Connect a DC Voltmeter to FMP108.
6. FM Demodulator
Connect a Test Generator to aerial input; Frequency
88.0MHz; f
Connect an AF Voltmeter to Loudspeaker Output.
7. Sliding Stereo
Connect Test Generator with Stereo Coder to aerial input;
Mono Transition
Frequency: 88.0MHz; E´ = 100µV (40dBµV); f
dev. 22.5kHz; Pilot dev. 7.5kHz.
Connect an AF Voltmeter to Loudspeaker Output.
8. Signal Level Offset
Connect a DC Voltmeter to FMP108.
AM: Connect a Test Generator to aerial input; Frequency
1008kHz; no modulation; E´ = 16µV (24dBµV);
FM: Connect a Test Generator to aerial input; Frequency
95.0MHz; no modulation; E´ = 7µV (17dBµV);
Calling up parameter sets:
Switch off the unit. Hold button
switch on the unit. Release button
was heard (abt. 5 seconds).
Press button
(abt. 7 seconds).
Press button
second).
AM: With buttons r
e.g. 00 1700 . Note the value U
FM: With buttons r
e.g. 02 1640 . Note the value U
Calculating the Offset Value W:
AM: U
FM: U
Offs
If U
Offs
if U
Offs
4
Preparation
= 1kHz; dev. = 22,5kHz; E´ = 2µV (6dBµV);
mod
¢ ¢ ¢ ¢ ¢
RADIO
¢ ¢ ¢ ¢ ¢
RADIO
again, until 2 peeps could be heard
¢ ¢ ¢ ¢ ¢
RADIO
¢ ¢ ¢ ¢ ¢
until 1 peep could be heard (abt. 1
TP
t select parameter 00:
TUNING
(here e.g. 1700).
AM
t select parameter 02:
TUNING
(here e.g. 1640).
FM
= U
- U
(in millivolts)
Offs
AM
FS
= U
- U
(in millivolts)
FM
FS
U
Offs
is negativ: W = 256 +
(see example 1);
20
U
Offs
is positiv: W =
(see example 2).
20
Align alternating with L06 at 87.5MHz for 2.0V
with C29 at 108MHz for 6.0V
Align with F603A for maximum Voltage.
Align with L02 for maximum Voltage.
Align with L04 for maximum Voltage.
Align with F101 for maximum Voltage.
Align with F106 for maximum AF Voltage.
Modulate left channel and adjust with R206 for 6dB cross-
: 1kHz;
talk attenuation in the right channel.
mod
Measure Voltage (U
Example 1:
depressed and
U
= 1700; Measured Voltage U
AM
only after 1 peep
U
= U
- U
Offs
AM
As U
is negativ: W = 256 +
Offs
W = 256 + (-7) = 249
Example 2:
U
= 1640; Measured Voltage U
FM
U
= U
- U
Offs
FM
As U
is positiv: W =
Offs
AM: With buttons r
e.g. 50 174 . Briefly press button
With buttons r
(e.g. W = 249: 50 249 ). Briefly press button
FM: With buttons r
e.g. 51 14 . Briefly press button
With buttons r
(e.g. W = 21: 51 21 ). Briefly press button
Adjustment Procedure
±
±
100mV.
in millivolts) and note it.
FS
= 1842mV;
FS
= 1700 - 1842mV = -142mV.
FS
U
Offs
= 256 +
20
= 1220mV;
FS
= 1640 - 1220mV = 420mV.
FS
U
420
Offs
=
= 21
20
20
t select parameter 50:
TUNING
.
¢ ¢ ¢ ¢ ¢
TP
t now set the calculated value
TUNING
t select parameter 51:
TUNING
¢ ¢ ¢ ¢ ¢
.
TP
t now set the calculated value
TUNING
¢ ¢ ¢ ¢ ¢
GRUNDIG Service
SEAT 3301
20mV and
-142
20
¢ ¢ ¢ ¢ ¢
again.
TP
again.
TP
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