2.4 TAPE TRANSPORT ADJUSTMENT8. When the FM waveform breaks in the level varying proc-
ess, subtly adjust the height of guide rollers at every
In most cases the deck section is in need electrical ad-
breaking point so that the waveform varies as flat as pos-
justment, it results from replacement of worm mechanical
sible.
parts or video heads. In the event of malfunction with elec-
Repeat the above steps 6. and 7. several times to con-
trical circuits, troubleshouting with the aid of proper test in-
firm that the waveform is flat as a whole.
struments most be done first, and then commence neces-
sary repair, replacement and adjustment, etc.9. Playback the SP stairstep signal of alighment tape and
adjust the tracking control to maximize the FM wave-
2.4.1 Back tensionform, confirm that FM waveform variation is always flat.
1. Set a cassette torque meter onto the deck and measure10. Record the signal and play it back in both of the SP and
LP modes, and confirm that the FM waveform is flat in
the back tension in standard REC mode to confirm that
-3-3both modes.
the back tension is 0.7x10 � 1.37x10 NYm.
2. If not, replace the tension band.Note:Among the above-mentioned adjustment steps,
When the value widely fluctuates in the measurement,the items of No.9 and No.10 are needed for the
replace the supply reel disk.LP model only.
3. With the cassette torque meter, confirm that the play
torque is 1.47x10-3 � 2.45x10-3 NYm.
CH-2
If necessary, replace the center pully unit.
1 field
Back tension
0.7x10-3 - 1.37x10-3 NYm
Flatten waveform.
(7-14gfácm)Play torque
1.47x10-3 - 2.45x10-3 Nám
(15-25gfácm)
Causer by wrong height
Caused by wrong height
of supply guide roller
of take-up guide roller
Fig. 2-4-2 FM waveform-1
Correct variation of waveform
Fig. 2-4-1 Cassette torque meter
2.4.2 Tape patternBad variation of waveform
1. Remove the Cover (JIG) shwon on Fig. 2-6-1 (Page 2-
10).
2. Connect the jig connector cable to CN25 on the MAIN
board as shwon on Fig. 2-6-1 (Page 2-10).
3. Observe signal at V. TP FM with external trigger from V.Fig. 2-4-3 FM waveform-2
FF on the jig connector cable.
4. Playback the SP stairstep signal of the alignment tape
and maximize the FM waveform by the tracking button.(P)
5. Set the tracking control to the center position by simul-
taneously pressing the tracking (-) and (+) buttons and
maximize the FM waveform by the tracking button.
6. If the observed FM waveform is not flat, adjust the height
of the supply of take-up guide roller with the roller driver.
Note:To prevent the tape from damage, turn the guide
rollers slowly.
7. By operating the tracking button (both in + and � direc-
tions) in the manual tracking mode, vary the output level
of the FM waveform from maximum to minimum and vice
versa to confirm that the waveform varies nearly in a flat
shape.
2-7 |
ACEC
