Sony TC-K670 - Mechanical Adjustment Procedures; Pinch Roller and Head Height Adjustment; Head Declination and Azimuth Adjustment; Tape Path and Waveform Check

Adjustment Method :
Supply Pinch Roller! :
Note: Only perform this adjustment when the supply
TC-K670/K877ES
pinch roller is to be replaced.
Insert the mirror cassette and put the unit in
record/playback mode.
Check to see whether the tape is curling at the
record/playback head guide or the pinch roller
guide.
If it is curling, remove the curl by adjusting the ®
tape curl adjustment screw. Then, check that the
tape is running past the middle of the erasehead.
Record/ playback Head
Note: Only perfom this adjustment when the record
/playback head is to be replaced.
Insert the mirror cassette and put the unit in
record/ playback mode.
(Height Adjustment) Check to see if the tape is
curling at the tape guide of the head. If it is
curling, tighten screws @, ©, and @, respectively
by the same angle, moving the head so that it
remains at the same angle throughout the
procedure. If it curls on the bottom side of the
mirror cassette (actually the inner side), tighten
all the screws equally; but loosen them if the
tape begins to curl on the top side (outer side).
ane = , Outside
normal Curling on the Curling on the
(record/playback head inner side. outer side.
as seen from the side Tighten screws Loosen screws
of the erasehead.) 4, ©, and @. @,®, and @.
(Declination Adjustment) While in the record/
playback position, set the back tension to 0 (wind
the supply reel with something thin like a pencil
in a counterclockwise direction) and make sure
there is no curling or shifting (shifting up/
shifting down) at the guide of the record/
playback head.
Because shifting can only occur due to a difference
in the width of the tape and that of the tape guides
(curling will otherwise occur), it is necessary to pay
close attention since it can be easily overlooked.
When there is a shift, tighten screws © and @ equally
and change the declination of the head. If the tape
is shifting up, tighten the screws, and if it is shifting
down, loosen them.
Repeat the adjustments in steps 2 and 3 and fine
adjust the height and the declination.
(Preliminary Azimuth Adjustment)
After demagnetizing and cleaning the adjustment
head, play back WS-48B (3 kHz, 0 dB).
Turn screw @ so that the reading on the level
meter of the unit or that of the level meter
connected to LINE OUT is maximized.
If the screw is turned at least half a revolution,
repeat the adjustments from step 1.
(Tape Path Check) Connect the oscilloscope to
LINE OUT and play back P~4-A100 (10 kHz, -10
dB) to display a resurge waveform. After 20
seconds of record/playback (after the tension
within the loop has been increased sufficiently),
make sure the variation in the resurge is within
+ 90 degrees (within +45 degrees is desired).
If the variation is greater than this, it is because
the declination and/or the height adjustment is
not perfect. Repeat the adjustments from step 1.
test tape
P-4-160
(10 kHz, ~10 dB) Oscilloscope
L-CH 47kQ
LINE CUT
Oscilloscope Resurge Waveform
OOAOOQV®
In Phase 45° cases 180°
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