Teac R-H300 - Playback Frequency Response; Bias Frequency Adjustment; Overall Gain Adjustment; Overall Frequency Response

Gerrits
PLAYBCK
FREQUENCY-RESPONSE
|
*
1. Test equipment connections are shown in fig. 4.
2. Playback the playback frequency response test tape.
3. Check shown in fig. 5 for both L-ch and R-ch.
AC EVM
LINE OUT =n
(Fig 4)
BIAS FREQUENCY ADJUSTMENT
1.
‘Test equipment connections are shown in fig. 6.
2. Load a CrO2 blank test tape.
3. Press the record and pause button.
4. Adjusts T303 for 105KHz frequency counter reading.
OVERALL GAIN ADJUSTMENT
PWN
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®Level up in high frequency range ...
® Level down in — frequency range ...
a
. Test equipment connections are shown in fig. 7.
. Insert the normal reference blank tape.
. Place UNIT into récord mode.
. Supply a 1KHz signal through ATT (- 1008) from AF oscillator
to line in.
. Adjust ATT until monitor level at TP31 (L- ae or TP32 (R-ch)
becomes 180mV.
. Playback recorded tape and make sure that the output level
at L-ch (Line out) or R-ch (Line out) becomes 180mV.
. If measured value is not 180mV, adjust it by using. VR13 (L-
CH) or VR14 (R-CH).
. Repeat from step (2).
OVERALL FREQUENCY RESPONSE
1.
Set a normal blank tape (MTT-5513) and record by apply sig-
nal (100Hz, 1KHz, 10KHz) through ATT-from AF oscillator to
lins in (Line out Level: 33mV).
. Playback the signal recorded in step 1, and check that the
level of each output frequency in within the range shown in
fig. 8 in comparison with the reference frequency (1KHz).
_ If it is not within the standard range adjust the bias current
by using VR31 (L-CH) or VR32 (R- ee so that. the | eaneniey
level is within the standard: :
neecene bias cur-
rent. He te
Decrease the bias
current,
Aiter that, increasé the signal recorded on Cro: blank tape
(MTT-5563) and metal blank tape (MTT-5572) up to 12KHz
and adjust in the same way as mentioned above and check
_that frequency level is within the range shown in Fig. 8.
PLAYBACK FREQUENCY RESPONSE
5dB
5dB
1 I
_ 40Hz 125Hz 10KHz 12.5KHz
chassis § {+
' Digital frequency
~ <Gounter S
LINE IN
AF oscillator
EVM 6° s(Oscilicscope
(Fig. 7)
EVM Oscillescope
dB
ao
63Hz 125Hz TOKH2 12.5KHz
(Fig. 8)
7
SERVICE
MANUAL.
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