Akai GXF 95 Service Manual

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Akai GXF 95 Service Manual

Extracted text from Akai GXF 95 Service Manual (Ocr-read)


Page 42

6. VERIFICATION OF ACTION OF AUTO
TAPE SELECTOR

Prepare a normal tape, CrO2 tape and metal tape with
a detection notch and verify that switching is auto-
matically made to the appropriate mode for the
specific tape set on the deck. Note that the tape
selector switch must be set to AUTO.

If the selector malfunctions, then adjustments de-
scribed in items 4 and 5 must be made once again.

7. BRAKE PLUNGER INSTALLATION
POSITION ADJUSTMENT (Refer to Fig. 54)

With the brake off (for example during REW), adjust
the brake plunger’s position with the installation
screws (21), (b) so that the distance between the tip
of the brake slide and the sub frame is 10.5 i 0.1 mm.

8. PINCH ROLLER PRESSURE
MEASUREMENT (Refer to Fig. 55)

Put in PLAY mode. Push pinch roller arm down with
the spring gauge, push the pinch roller 1—2 mm from
the capstan and release slowly.

Read the spring gauge at the moment the pinch roller
touches the capstan and begins to ratate. Specified
contact pressure measurement of 380 i 50 gm. If no
measurement is obtained, replace the pinch roller
spring.

9. WINDING TORQUE MEASUREMENT
IN EACH MODE

Insert cassette torque meter and measure in each
mode.
For fast forward and rewind measure at the end
of the tape when the tape has stopped running.
The specified torque is:
Playback : 30 to 50 g-cm.
Fast Forward,Rewind : 70 to 120 g-cm.

41

Page 46

REAR

Fig. 61 Syscon P.C Board (CU-5214A)

MORE THAN 4V

W_—_t

LESS THAN IV

Fig. 62

3. PHONO COUPLER LEVEL ADJUSTMENT
(Refer to Figs. 61, 62)

1) Connect an oscilloscope to TH and tum VRl
(500 ohms) on the Syscon P.C Board fully clock-
wise.

2) Remove tape from a cassette pack and prepare an
empty pack.

Set it on the equipment and turn the MODE
switch to F. FWD.

3) Confirm the waveform on the Oscilloscope is as
shown in Fig. 62.

4) If the High Level is not more than 4V, adjust VRl
(500 ohms) to get the High Level of 4V.

45

Page 51

. Test Tape Adjustment
Step Adjustment Item Supply Signal Mode Point Result Remarks
Normal
VR4 50K
12 Recording Level #0233: REC/ CrO2 :3; 311:")
Adjustment {6' d. PLAY VRS 50K '41‘ 0 m
cor mg Metal ( mV)
VR6 50K
Distortion 1,000 Hz REC / Normal: Less than 0.7%
13 Factor —5 .5 dBm PLAY CrO; : Less than 0.6% Refer to NOTE 8.
Confirmation Recording Metal : Less than 0.6%
. 19 kHz Minimum AC MPX Filter to ON.
14 IZEEIEESI from an REC DOSE?” K Voltmeter Refer to NOTES
J Oscillator indication 9, 10.
NOTES: 1. Output Level Control should be at maximum.
2. Because each of these adjustments are vital to perfect Dolby NR circuit operation, be sure that they are

carried out with as little error as possible.
Set Auto Tuning Mode Selector to REFERENCE Mode.
. Except for Step 14, set MPX Filter Switch to OFF Position.
. Use the following cassette measuring tapes:
Normal Tape : Maxell UD C-6O
CrO; Tape : TDK SA 060
Metal Tape 2 TDK MA-C G60
6. Stop the recording bias oscillator while making record peaking adjustment (Refer to Figs. 65, 66).
7. As the same earth line is used for both the Lch and Rch, adjust the Lch with the Rch lead wire (PNK)
detached and the Rch with the Lch (WHT) lead wire detached.
8. If it does not comply with the specifications, repeat Steps 8 to 11 and readjust.
9. Adjust the oscillator’s frequency to give a frequency counter reading of 19.00 kHz.
10. Unless the core is moved unintentionally this adjustment is not necessary.

arr-hf»

50

Page 52

. BAR METER ADJUSTMENT (Refer to Figs. 64, 67)

AC VOLTMETER
Lch Rch

GX‘F95 ,, a n O
L, L
L
OSéIlIiTRTOR '—m5 “333? Ch
( | KHZ) Rch
GND T.P(Rch) T.P(Lch) ,
>
" o " 0
Lo Lo ‘
L ch R ch
DIGITAL VOLTMETER
Fig. 67 Instrument Connection
Adjustment . Adjustment
Step Item Supply Signal Point Result Remarks
1 Input Level 1 kHz from LINE REC 251% 23%
Setting an oscillator Volume
(LINE OUT)
Set the PEAK/VU button to VU.
VU M0“ 1 kHz from VR7 100K (L611) 1.52v i 0.05V Connect a Digital Voltmeter
2 DC Voltage an oscillator VRS 100K (Rch) (TP Out ut) between TP4 (uh) and TPS
Adjustment (Tuning PCB) p (Rch)
B“ M?" 1 kHz from VR9 20K _ 9 dB. Tum °ff the. ”35““ °f0 “.3.
3 Sensmwty an oscillator (Tunin PCB) Indication once and adjust it to the posmon
Adjustment 3 (Bar Meter) where it completely lights.
_ Set the PEAK/VU button to
Peak Mode 1 kHz from VR8 500K (Lch) -7 dB PEAK. Turn off the segment of
4 Sensitivity an oscillator VR6 500K (Rch) indication —7 dB once and adjust it to the
Adjustment (Tuning PCB) (Bar Meter) position where it completely
lights.

NOTES: 1. Adjust when 3 secs have elapsed after the power is switched ON.
2. Put the monitor switch to SOURCE and the output volume to Maximum.

51