Akai 1730 SS Service Manual

Page 2

TABLE OF CONTENTS

SPECIFICATIONS ............................... 2
MEASURING METHODS ......................... 3
CONTROL LOCATIONS .......................... 5
DISMANTLING 0F TAPE TRANSPORT UNIT

& AMPLIFIERS ................................. 6
TRANSPORT MECHANISM ....................... 8
MECHANISM ADJUSTMENT ....................... 12
AMPLIFIER ADJUSTMENT ....................... 14
MAINTENANCE PROCEDURES ................... 16
TROUBLE SHOOTING CHART ................... 17
COMPOSITE VIEWS OF COMPONENTS ............ 22

SCHEMATIC DIAGRAM

When placing order for parts, please use Separate
PARTS LIST or PRICE LIST FOR PARTS.

Page 10

" , /" 4. FAST-FORWARD MECHANISM

Turning the FAST FWDeREWIND LEVER (A) to
FAST FWD position, causes cam (B) under the knob
to push up Lever (C) Idler (D) moves into the space
between Plastic Roller (F) above the Take-Up Reel
Spindle and the upper part of the rotating motor drive
bushing to transmit the motor rotation to the take-up
reel spindle. At the same time, Brake Rollers (H) and (I)
come off the reel spindle to free Supply Reel Spindler
(G) and (F), thereby allowing fast winding of the tape
onto the take-up reel.

(See figure 3)

5. REWIND MECHANISM

Turning the FAST FWDAREWIND knob (A) to
REWIND position, causes cam (B) under the knob to
push up Lever (C). Idler (D) moves into the space
between the upper part of the rotating Motor drive
bushing (E) and the Intermediate Pulley (F) to transmit
the high-speed rotation of the motor through the
intermediate pulley to Supply Reel Spindle (G), At the
same time, Brake Rollers (H) and (I) come off the reel
spindle to free take-up reelspindles (J) and (G), thereby
rewinding the tape onto the supply reel at a fast speed.
(See figure 4)

6. STOP CONTROL

Turning the stop lever to STOP" position, causes Brake
Rollers (A) and (B) to depress the reel spindles andstop
rotation.

As the brake rubbers depress the plastic rollers below the
reel spindles, no friction is applied to the tape.

(See figire 5)

Take-up l
Slde Brake ,
l
. Take-up Rewind Take-up 5m ly
Modes of Operauon my, ldlcr Idler side all;
Wheel Wheel Brake B'ak e
3) STOP x x X 1/ 1
(h) FAST-FORWARD x e x x l
m REWIND x x o x t
F1g- 5 WRECORDING ; O x
IlAYBACK l X
A 7

NOTES : X-markx indicules "open" and

rmlukfi engaged"

Page 18

IX. TROUBLE SHOOTING CHART

SECTION A" TROUBLE WITH AMPLIFIER
1. Playback Problems (unit set to play position) ;

Symptom Trouble

Nu sound from Line-Out jack
(No B(+) voltage supply) 1. Silicon diode (10DC71 BLK) defective
2. R402 (18 fl 3 W) or TR401 (250123) defective

(BU) voltage supply) 1. Check transistor TRZOI and TR202
2. Check lC-201 (LB-3141)

3. Playback head coil open or lead wire loose.

No sound from speaker
(No B(+) voltage supply) 1. Silicon diode D401 ~404 (V068) defective
Fuse (0.7 A) defective

3. Check source/Tape monitor switch

(B(+) voltage supply) 1. IC~301 (STK~-011) defective

Sound, but volume insufficient
(Eh) voltage low) 1. Silicon diode D405 (loDC-i BLK) defective
2. R4u2'(ia n 3 W) or TR401 (2513223) defective

(B(+) voltage normal) 1. Dirty head
2. Check transistor (TR-7.01, 202)
3. Check IC-Zol (LD-3l4l)

Loud hum ¥
(Hum is decreased if playback l. Playback head shield or insulation defective

head is grounded)

(Nu rlmugc even when playback 1. Ground wire loose

head is grounded) 2, (3401, 402 (220/50) defective
Loud hum

(Inductive pick-up) 1. Ground the recorder

2. Change the set position of the recorder

Irregular scratching or crackling noise 1. Transistor TRZOI, 202 defective
2. 1c-201 (LB-3141)defective
3. Check playback card (LF-5022)

Squeaking noise 1. Dirty head
2. Tape itself defective

Hissing noise

(Noise present when playing 1. Head is magnetized

tape) 2. Tape itself defectiye

(Not caused by tape 1. Transistor TR-2ol, 202 defective

Lack of treble 1, Poor contact between head and tape (Dirty head or back tension weak)
2. Head angle incorrect
3. Head worn~out
4. Tape itself defective

Sound distorted . Dirty head
2. Defective transistor TR-ZO], 202

3. Head worn out

17