Grundig Studio RPC 100/a Serviceanleitung Seite 7

b) Electrical: Record,playback,(right-left-identification)
oscillator switch, tape type selector switch, variable
fade Wout when recording.
h) Checking the active S kHz-filter
All programme buttons released
Feed in R 1088 (12 kQ) approx. 100 mV,ms
(Rgp,t 200 Q). Measure on the hot end of the LS-con-
trol.
Refcronce frequency I kHz O dB
Measuring frequency 2.5 kHz 4- 2.5 dB
Measuring frequency 5 kHz —12.5dB
IV. Adjustment of tuning voltage
Switch on UKW (FM) and sensor "U"
AFC "off"
Digital voltmeter to M 2
Rotary capacitor open
n.djust voltage IJI with R 1103to 30 V ± 100 mV
Potary capacitor closed
Adjust voltage I-J2 with R5001to 2.7V ± 50mV (note meter
errors).
V. FM-IF-RF-alignment
Before aligning set controls R 1035/ R 1046 to middle,
R1049 to left end stop.Core @to inner maximum.
VHF wobbulator via balun (240 Q) to aerial sockets.
Receiver to "VHF" (FM) and sensor "U" on, "AFC" and
"muting" off.
Scale pointer to 88 MHz-mark
VVobbulator-scope with AF-probevia 47kQ to point V.
Wobbulator to 88 MHz mid-frequency. The alignment is
carried out with the lowest possible RF-voltage. Trace the
signalwith cores@ , and (sequence i s impor-
tant). Note image and other multiple disturbing frequencies.
With core @ ull the curveto the 88MHz mark.Now
align circuits O, and @ for maximumand
symmetry.
Scale pointer to 106 MHz mark. Wobbulator to 106 MHz
Tracethe signalwith trimmer@ and adjustthe curveto
the 106 MHz-mark on the scope.
Thenaligntrimmer@ and for maximum andsym-
metry.
At 88MHzalign with@ , and , and at 106MHz
alignwith@ @ and . Repeat a lignments s everal
timesandterminate with@ and
Cores:@ innermaximum
@ outermaximum
VI. Demodulator alignment
The alignment is carried out with lowest possible RF-
voltage. Wobbulator-scope with AF-probe via 47 kQ to
pointV. Alignwithcircuit@for symmetrical S-curve.
Core: inner maximum.
VII. AFC centre tuning
Receiver and wobbulator as in paragraph V, but set to
small deviation (40 kHz); AFC still "off". Connect a DC
millivoltmeter with 0-centre indication (± 50mV) between
andV.
T e middle frequency of the wobbulator must be identical
to the IF and demodulator alignment.
With R 1046 adjust for OV indication on the millivoltmeter.
AFC check:
Detune receiver and switch in AFC. The signal must be
pulled in from the left and right Of the main frequency.
VIII. Alignment of the tuning meter
VHF generator with 40 kHz deviation at f 88 MHz to
aerial sockets. Set scale pointer of receiver to 88 MHz-
mark. With a signal voltage of 1 mV adjust R 1035so that
the pointer of the meteris over the markingpoint near8.5.
Stereo decoder alignment
For alignment the following instruments are required.
Stereocoder SC5, oscilloscope G 10/13 (or similar) with
test probe TK8/9 (RE 10MQ), low pass filter fg 15 kHz,
AF-voltmeter MV5 or similar. Receiver to VHF, stereo.
Connect 4 Q load resistors to LS-sockets. Volume control
to first tap, set amplifier for linear frequency response.
Signal level 200ltV/240Q, tune receiver accurately and
switch AFC "on".
a) Alignment of the 19 kHz-circuits 09223-647.22
and09223-648.22 0
Scopewith probe 10: I to point V. Modulatesignal
with 19kHz pilot, 100/0pilot deviation 7.5kHz de-
viation). Alignment and for maximum oscillo-
gram height.
Core positions: Outer maximum
b) Alignment O fthe38kHz-circuit 0 9223-649.22@
Scopewith probe10: I to point V. Signalsame asfor
IXa). A lignment (D for maximum o scillogram height.
Core position: Outer maximum
Alignment o f thesideband-circuit 09223-650.22 @
c)
Scope withprobe 10:1 to pointV. Align@
for
maximum amplitude and sharp cut-off points.
(R — pilot Off.
Core position: Outer maximum
d) Pilot phase alignment
Connect AF-voltmeter to the left hand channel loud-
speaker output via the low pass filter fg =
15 kHz. Gen-
erator: Modulated with I kHz "S", pilot on (10% de-
viation
Align H for maximum AF-output voltage.
e) Stereo sensitivity adjustment (R 1049)
Generator as under IX a) but with 5% pilot deviation
3.75 kHz). R 1049 right end stop, stereo lamp ex-
tinguishes. Slowly turn to the left until the lamp just
illuminates.
f) Cross-talk damping (R 306, 307)
Stereocoder SC 5, 100/0pilot deviation, I kHz.
Depress button "R". Connect AF-voltmeter via low pass
filter (fg 15kHz) to left channel loudspeaker output
and adjust with R306/R307 to minimum. Depress but-
ton "L" and measure right channel, if necessary adjust
with R 306/R 307.
RFstereo sensitivity adjustment
g)
Generator with 6-7.5 kHz pilot deviation, level 20 gV
on 240 Q, tune receiver accurately, AFC "on"
R1033 to right end stop, lamp extinguishes. Slowly
turn to the left until the lamp illuminates. Reduce RF
level by approx. 20 dB, lamp must extinguish again.
X. AM-IF-alignment
The alignment should be carried out with smallest pos-
Sible voltage.
Wobbulator t o V. Scope to V.
The middle frequency is determined by the ceramic filter.
Aligncircuit and@ for maximum andsymmetry.
Core positions: Outer maximum
AM-oscillator and input circuit alignment
Range Image
Frequency Input Sensitivity Rejection
Pointer Pos. Oscillator Circuit
160 kHz @ Max. 9 3260
@ Max.
LW
290 kHz (D Max. 15 3780
560 kHz Max.
O Max. 15
MW
@ Max. (D Max.
1450 kHz 26
6.1 MHz O Max. 10
(D Max.
(SW)
15 MHz @ Max. @ Max. 11 8.5
XII. Alignment of the tuning meter (AM)
At approx. I MHz and 500mV generator output voltage
(fmod1 kHz 30%), adjust R1032so that the pointer of the
meter is over the marking point near "8.5". With RF-volt-
age switched off adjust R1038 to that the pointer is over
the "O" mark. One adjustment affects the other, therefore
repeat alignment if necessary,terminate with R 1032.
Osc. voltage
on Point 4
TCA 440 Remarks
79 mV
96 mV
Ali n alternating L and C, finish off with
C-a%ignment.
I-side: Pointer to zero-marking.
66 mV
Core positions: Outer maximum.
90 84 mV
6 dB
25 78 mV
82 mV
Remarks:
For the cassette unit CB 200 separate service manual
(CB 200 / CB 210) is available.