Bias Oscillation Frequency Adjustment; Recording Bias Adjustment; Recording Level Adjustment - Pioneer XR-A6800 Service Manual

XR-A6800, XR-A4800
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Recording Adjustment

(1) Bias Oscillation Frequency Adjustment

Input Signal/
Step Mode
Test Tape
Load the STD-632 test
1 REC tape and set the
recording mode.

(2) Recording Bias Adjustment

• Since this adjustment affects recording bias, prevent distortion from increasing due to underbias.
Step Mode Input Signal/Test Tape
Input a 315 Hz signal to the
1 REC
AUX terminal and set the input
selector to AUX.
Load the STD-632 test tape and
REC → record/playback the 315Hz and
2
10kHz signals
PLAY
(see the Note below)
Note : Set the 10 kHz input signal level to the same value as the 315 Hz input signal level of step 1.

(3) Recording Level Adjustment

TE
L 13942296513
Step Mode Input Signal/Test Tape
Input a 315 Hz signal to the
1 REC
AUX terminal and set the input
selector to AUX.
Load the STD-632 test tape and
REC →
record/playback the 315Hz
2
PLAY
signal.
(4) ALC Operation Check
Step Mode Input Signal/Test Tape
Input a 315 Hz signal to the
1
REC/
AUX terminal and set the input
PAUSE
selector to AUX.
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Adjusting Points
Deck ΙΙ
L2801
Deck Ι
(AF Assy)
Adjusting Points
Deck ΙΙ
Deck Ι
Input signal level
Deck ΙΙ
VR2801 (L ch)
Deck Ι
VR2802 (R ch)
Adjusting Points
Deck ΙΙ
Input signal level
Deck Ι
Deck ΙΙ
VR2301 (L ch)
Deck Ι
VR2302 (R ch)
Adjusting Points
Input signal level
Set to a level + 10dB above the
input level at step 1.
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Measurement Adjustment
Points Value
Oscillation
frequency to be
Between A
105.0kHz ±
point Fig. 7
2kHz.
and GND
Measurement
Points
TAPE TEST
POINT (L, Rch)
(AF Assy)
TAPE TEST
POINT (L, Rch)
(AF Assy)
Q Q
3 6 7 1 3 1 5
Measurement
Points
TAPE TEST
POINT (L, Rch)
(AF Assy)
TAPE TEST
POINT (L, Rch)
(AF Assy)
Measurement
Points
TAPE TEST
POINT (L, Rch)
(AF Assy)
co
.
9 4 2 8
Remarks
If the REC/STOP button for four
seconds while the power is in STAND
BY mode, the frequency will decrease
2 to 3 kHz.
Adjustment Value Remarks
– 23.7 dBV
Repeat adjustment until playback level
of the 10kHz signal is within 0 ± 0.5 dB
from that of the 315Hz signal.
0 5 8 2 9 9 4 2 8
Adjustment Value Remarks
– 7.7 dBV
Repeat recording, playback and
adjustment until playback level of the
315 Hz signal becomes – 7.7 dBV.
Adjustment Value Remarks
– 8.2 dBV
Confirm that the reading is
– 2.2 ± 2.5 dBV.
m
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