Denon DR-M22 - Electrical Section Adjustments

a
8. Adjusting the Reel Thrust Movement
Check to make sure that the reel thrust movement is
within 0.2—0.4 mm.
9. Checking the FF and REW Torques
* When using the cassette type torque meter.
Check to make sure the torque meter indicates more
than 70 g-cm at the end of FF and REW.
“When using a modified cassette half.
Load the modified cassette half; hook the end of the dial
tension meter (full scale 100-300 g) onto the triangle
section. In the FF (REW) mode, feed the tape in at a
rate somewhat slower than the take up speed. Check
to make sure the dial tension meter reads more than 60
g-cm.
10. Checking the Back Tension Torque During
Record/Playback
Load the cassette type torque meter; check to make sure
the torque meter reads between 7 ~ 13 g-cm during play-
back and that there is no unevenness.
If it is not within this range, check the section on adjust-
ing the reel trust movement; or replace the spring 109.
11.
Checking
the
FF
and
REW
Times
Load
a
C-60
cassette
tape;
check
to
make
sure
the
tape
is
fast
forwarded
or
rewound
within
70-110
seconds.
If
it is not
within
this
range,
check
sections
8
and
10.
12.
Checking
the
Operation
of
the
Erase
Preven-
tion,
Metal
and
Chrome
Switch
Operation
Arms
Check
to
make
sure
the
operation
arms
58,
59
operate
the
switches
positively,
depending
on
whether
or
rot
there
are holes.
13. Checking the EJECT Switch 75
To
check
the
operation
of
the
EJECT
SW
with
only
the
mechanism
unit,
make
sure
the
angle
205
operates
the
switch
positively
when
the
hook
lever
203
is
operated.
14. Checking the Gap Between the Pulse Detection
LED and the Reel Ass’y
Check to make sure the gap between the surface of the
shutter section of the reel ass'y and the LEDs is approxi-
mately 1mm.
25 Reel Ass’y
LED
{
Approximately 1 mm
~114~—
| ADJUSTING THE ELECTRICAL SECTIONS
@ Measuring instruments necessary for adjustments
(1) Audio signal generator
(2) Variable resistance attenuator
(3) Electronic voltmeter
(4) Oscilloscope
(5) Frequency counter
(6) Adjustment screwdriver
(7) Trap coil adjustment square stick
(8) Test tapes (TEAC MTT-111, MTT-114, MTT-150 )
(A-BEX TCC-262)
(DENON DX 3, DXM, DX7/50N, LX)
(9) Transport Check cassette tape
(SONY MC-112C) Mirror tape
® Cautions on adjusting
(1) Before adjusting, clean the head surface, capstan anc
the pinch roller with a gauze or a cotton swab moisten
ed with alcohol.
(2) Demagnetize the R/P HEAD and the E. HEAD with ;
head eraser.
(3) Completely demagnetize the adjustment screwdriver
(4) Unless instructed otherwise, set the various control
as follows:
— INPUT volume ...............0.0. maximun
— OUTPUT LEVEL volume .......... maximun
— DOLBY NR switch .......... 0.00.00. OFF
— MONITOR switch ........... 0.0.00. TAPE
1. Tape Transport Check
Load the transport check cassette. In the operatior
mode, illuminate the fixing guides of the R/P HEA
with a lamp and check to make sure the tape edge do
not come in contact with the tape guidesection.
The tape transport is the most important element in ¢
terming the performance of a cassette deck.
Avoid
moving
the
various
adjustment
screws,
nuts,
etc.,
much
as
possible.
The
M-300
Tool
Plate
is
a
tool
used
pr
marily
for
precisely
adjusting
the
height
of
the
tape
guic
attached
to
a
tape
head.
This
tools
is
indispensable
in
repairing
various
heads,
whe
replacing
heads,
and
for
design
purposes,
in
order
to
dete
mine
the
location
measurements
for
mechanical
attact
ments.
Even
when
the
height
of
the
tape
guideis
accurately
mea
ured,
during
actual
tape
play,
the
tape
may
sometime
warp.
This
is
due
to
slight
errors
in
dimensiyms
of
those
part
which
actually
come
in
contact
with
the
tape,
such
as
ca:
sette
halves,
heads,
pinch-rollers,
capstan
shaft,
etc.
There
fore
a
mirror
tape
is
used
to
confirm
proper
running
of
th
tape.
In
this
way,
the
M-300
Tool
Plate
and
mirror
tape
are
bot
used
to
insure
good
tape
running.