Mechanical Adjustments - Nakamichi BX-125 Service Manual

ees Sanath
2. TEST TAPES AND GAUGES
(1) 400 Hz Level Tape (DA09005B)
(2) 1 kHz Track Alignment Tape (DA09007B)
(3) 15 kHz Azimuth Tape (DA09004B)
(4) 3 kHz Speed and Wow/Flutter Tape (DA09006C)
(5) 10 kHz PB Frequency Response Tape (DA09003B)
(6) 15 kHz PB Frequency Response Tape (DA09002B)
(7) 20 kHz PB Frequency Response Tape (DA09001B)
(8) Tape Travelling Cassette (DA09027B)
(9) Reference EXII Tape (DAO9066B)
(10) Reference SX Tape (DA09025B)
(11) Reference SX-E Tape (DA09086A)
(12) Reference ZX Tape (DA09037B)
(13) Head Alignment Gauge (DA09092A)
3. MECHANICAL ADJUSTMENTS
3.1. Tape Guide Height Check for Record/Playback Head and
Erase Head
With use of a Head Alignment Gauge, tape guide height check
for the Record/Playback and Erase Heads shall be made, wherein
a small block shall be pushed straight down to the base while in
use of the Head Alignment Gauge. Refer to Fig. 3.1.
(1) Record/Playback Head Tape Guide Height
(a) Load the base of the Head Alignment Gauge carefully and set
the cassette deck in Play mode.
(b) Place the small block of the Head Alignment Gauge on the
base.
(c) Slide the small block against the tape guide of the Record/
Playback Head, and check to insure that the block is ac-
cepted by the tape guide,
(d) If not, loosen the screw and insert a shim (either 30 um
(0C80048A), 60 um (0C80038A), or 100 um (0C80039A))
to raise the Record/Playback Head, then tighten and apply a
quantity of lock tight paint to the screw.
(2) Erase Head Tape Guide Height
(a) Load the base of the Head Alignment Gauge carefully and set
the cassette deck in Play mode.
(b) Place the small block of the Head Alignment Gauge on the
base,
(c) Slide the small block against the tape guide of the Erase
Head, and check whether the block is accepted by the tape
guide,
3.2, Head Base Stroke Check
Refer to Fig. 3.2.
{1) Load the base of the Head Alignment Gauge carefully, then
push the base toward the Record/Playback Head to eliminate
the clearance between the reference pin and the base.
(2) Set the cassette deck in Play mode.
(3) Place the small block of the Head Alignment Gauge on the
base,
(4) Contact the small block with the Record/Playback Head
surface and the Erase Head surface, and check whether the
end of the small block is located within the specified toler-
ance as shown in Fig. 3.2,
3.3. Record/Playback Azimuth Alignment and Height Check
Refer to Fig. 3.1.
(1) Connect a VTVM to the Output Jacks,
(2) Load a 15 kHz Azimuth Tape and set the cassette deck in
Play mode,
(3) Turn the Azimuth Alignment Screw until the outputs of both
channels become maximum.
(4) Load a 1 kHz Track Alignment Tape and set the cassette
deck in Play mode,
(5) Check to insure that the readings of both channels on the
VTVM are below —25 dB.
If not, replacement of the Record/Playback Head will be
required.
(6) Apply a quantity of lock tight paint to the Azimuth Align-
ment Screw,
Shim