UMS 1 / UMS 2 Abgleich / Alignment
GRUNDIG Service 2 - 9
Adjustment Preparations Adjustment Procedure
9. Head current
(coarse)
10.Head current
(fine)
11.Bias voltage
(coarse)
12.Frequency
adjustment
during recording
13.Distortion factor
With SVR104 (left channel) and with SVR204 (right
channel) set to test points L. REC und R. REC 6.0mV.
When recording on Fe IEC I-cassettes the voltage must be
4.5mV.
V
o
= 23mV at the test points L. DOLBY and R. DOLBY
during recording.
On playing back the recording made on the cassette
recorder, a voltage level of 23mV ± 0.5dB must be present
at the test points L. DOLBY and R. DOLBY.
If the level differs from the value above re-adjust the head
current control SVR104 (left channel) or SVR204 (right
channel) during recording.
When recording on Fe IEC I-cassettes the voltage must be
23mV ± 1dB.
With Cr-cassettes, set the voltage level to 14.5mV at test
point L. REC or R. REC. with SVR103 (left channel) and
SVR203 (right channel)
With Fe-cassettes the voltage must be 12mV.
When playing back the recording the levels at the test
points L. DOLBY and R. DOLBY must not differ by more
than 0.5dB.
If V
o
f
2
to V
o
f
1
is higher than 0.5dB correct the bias.
Re-adjust with SVR103 (left channel) or SVR203 (right
channel).
V
o
f
2
(12.5kHz)
V
o
f
1
(400Hz)
Distortion analyzer to test point L. LINE OUT or R. LINE
OUT (47kΩ termination).
Function: Playback-Start
Dolby off
Distortion factor measured on playing back the recording
made:
Fe IEC I K
3
≤ 1.5%
CrO
2
IEC II K
3
≤ 2.5%
≈
10k
10k
AUX
L
R
≈
10k
10k
AUX
L
R
≈
10k
10k
AUX
L
R
AF-voltmeter to test point L. REC (left channel) or to test
point R. REC (right channel).
Connect AF-generator to AUX sockets.
V
i
= 50mV, f
= 1kHz.
Switch the bias off by short-circuiting the base and emitter
of transistor T123 (OPT 1).
Insert a recordable cassette, Cr (IEC II).
Function: AUX
Record-Start
Dolby off
AF-voltmeter to test point L. DOLBY (left channel) or to
test point R. DOLBY (right channel).
Insert a recordable cassette, Cr (IEC II).
Connect AF-generator to AUX sockets.
V
i
= 50mV, f
= 400Hz.
Function: AUX
Record-Start
Dolby off
–
Playback-Start
AF-voltmeter with a 1:1000 capacitive voltage divider to
test point L. REC (left channel) or R. REC (right channel).
Insert a recordable cassette Fe or Cr.
Function: Record-Star
AF-voltmeter to test point L. DOLBY (left channel) or to
test point R. DOLBY (right channel).
Insert test cassette 448 A, side B (blank part) Cr (IEC II) or
similar tape.
Connect AF-generator to AUX sockets.
V
i
= 23mV, f
1
= 400Hz, f
2
= 12.5Hz.
Function: AUX
Record-Start
Dolby off
–
Playback-Start
Connect AF-generator to AUX sockets.
V
i
= 500mV, f
= 333Hz.
Insert test cassette 448 A,
side B (blank part) Cr (IEC II)
or similar tape.
Function: AUX
Record-Start
Dolby off
≈
10k
10k
AUX
L
R
= 0dB ± 0.5dB
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