Abgleichvorschriften / Adjustment Procedures
PA 6
2 - 5
GRUNDIG Service
Tape Deck
Measuring instruments / equipment:
Frequency counter, AF voltmeter, AF generator, Wow and flutter meter, Cr test cassette, Torque test cassette.
With adjustment control R482 (Logic board) set the fre-
quency to 3150Hz
±
1.0%.
On START, the torque should be 30 to 60 x 10
-4
Nm
≈
40g-cm.
Deviation
≤
0.1% (IEC wtd).
Playback measuring time
≥
30 seconds.
Tape direction: "Normal"
With the head adjustment screw
E
set the left or right
channel to maximum level.
Then connect the left channel in parallel with the right
channel (AUX OUT). By minimum readjustment of the head
adjustment screw
E
set the output level to maximum.
Turn around the test cassette.
Tape direction: "Reverse"
Adjustment with head adjustment screw
F
for the same
level as in the "Normal" tape direction.
Set the playback level with the adjustment controls R135
(left) resp. R136 (right) to 490mV
±
0.5dB.
When using a test cassette with 200nWb/m set the playback
level to 388mV
±
0.5dB.
The oscillator frequency should be 85kHz
±
10kHz.
Adjust with L111.
Erase current: 150mA
±
10% measured at R263
= 150mV
±
10%.
Adjust for minimum RF with F111 at test point TP3 (left
channel) and F112 at test point TP4 (right channel).
Set the input level during Record so that at 315Hz the
voltage measured at the test points
D1 and
D2 is
388mV (= 0dB).
At 19kHz: U
o
≤
12mV (
≤
–30dB).
Adjust with F101 (left channel) resp. F102 (right channel).
Open wire bridge B407.
If the levels between V
o
f
1
(250Hz) and V
o
f
2
(12.5kHz) at
D1 and D2 differ by more than + 1.5dB cut the bridges
B1 (C101), B2 (C103) left channel, or the bridges B3
(C102), B4 (C104) right channel.
V
o
f
2
(12.5kHz)
V
o
f
1
(250Hz)
Adjustment
Preparations
Adjustment Procedure
Frequency counter to AUX OUT.
Insert test cassette.
Play back 3150Hz.
Load the torque test cassette.
Function: Start.
Wow and flutter meter to AUX OUT.
Load test cassette.
Play back 3150Hz.
Connect AF-voltmeter to AUX OUT L (left channel) or to
AUX OUT R (right channel).
Load test cassette, play back 10kHz.
AF-voltmeter to test point D1 (left channel) or D2
(right channel).
Insert test cassette.
Play back 315Hz (250nWb/m).
Dolby off.
Frequency counter to test point L1 (R263).
Insert a recordable cassette with CR tape (IEC II).
Function: Record-Start.
AF-voltmeter to test point L1 (in parallel with R263).
Insert a recordable cassette with CR tape (IEC II).
Function: Record-Start.
Connect the AF-voltmeter to test point TP3 (left channel)
or to test point TP4 (right channel) on the audio circuit
board.
Insert a recordable cassette with CR tape (IEC II).
Function: Record-Start.
Connect the AF-generator (f
1
= 315Hz, f
2
= 19kHz) to the
AUX IN sockets.
Close wire bridge B407.
Connect the AF-voltmeter to the
test points D1 (left channel)
or D2 (right channel).
Insert a recordable cassette with
CR tape (IEC II).
Function: Record-Start, Dolby off.
AF-voltmeter to test point D1 (left channel) or test point
D2 (right channel).
Insert test cassette.
Play back the 250Hz / 12.5kHz frequency recording on the
tape.
Dolby off
F
E
Tape run
"Reverse"
Tape run
"Normal"
1. Tape speed
2. Take-up torque on
Start
3. Wow and flutter
4. Head gap angle
(Azimuth)
5. Playback level
Reference tape
scanning
(Dolby level)
6. Erase frequency
7. Erase current
8. Record blocking
circuits
(bias filter)
9. MPX-filter
(19kHz stereo pilot
tone)
10.Frequency
response on
Playback
≈
10 k
10 k
AUX IN
= 0
±
0.5dB
Dolby noise reduction under license from Dolby Laboratories Licensing Corporation.
„DOLBY“ and the double D Symbol
g
are trademarks of Dolby Laboratories Licensing Corporation.
NR = Noise Reduction.
