Tascam 246 Portastudio Service Manual

Page 2

246

1.
2.

3.
4.

(DmVGIO'I

TABLE OF CONTENTS

SPECIFICATIONS AND SERVICE DATA ..... 2 N 3
CIRCUIT DESCRIPTION

2-1 Outline ............................ 4
2-2 Control Circuit ....................... 4
23 Record, Playback Circuit ............... 12
MAJOR PARTS LOCATION ................ 15
MAINTENANCE

4-1 Adjusting Tools and Equipment ........... 17
4-2 Definition and Measurement Conditions ..... 17
4-3 Disassembly of Major Parts ............. 17

4-4 Check and Alignment of Tape Deck Section. . . 18
4-5 Signal Path and Response Check

of Mixer Section ..................... 21
4-6 Record/Playback Amplifier Checks
and Adjustments ..................... 27
. EXPLODED VIEWAND PARTS LIST ...... 33'\,42
. PCB BOARDS AND PARTS LIST ......... 43 N 66
. BLOCK DIAGRAM ...................... 57
. LEVEL DIAGRAM ...................... 69
. IC INTERNAL CIRCUIT .................. 71
PRECAUTIONS

Value of "dB" in the Data refers to 0 dB (1V), except
where specified.

The AC voltmeter used in the procedures must have an
input impedance 011 M-ohms or more.

Resistor values are in ohms (It = 1,000 ohms. M =
1,000,000 ohms).

All capacitor values are in microfarads (D = Dicofarads).
A parts marked with this sign are safety critical com»
ponents . They must always be replaced with identical
components - refer to the TEAC parts list and ensure
exact replacement.

Improvements may result in Specifications and Service
Data changes.

dbx noise reduction system made under license from
dbx, incorporated. The name "dbx and thedbx symbol
are trademarks of dbx, Incorporated.

1. SPECIFICATIONS AND
SERVICE DATA

MECHANICAL CHARACTERISTICS

Tape

Track Format
Head Configuration

Motors

Tape Speeds!)

Speed Accuracy
Pitch Control
Fast Wind Time

Pause Start Time

Dimensions (W x H x D)

Weight (net)

Compact cassette,
70115, Hi-bias (Type II) tape
4-track, deltannel

1 Erase, 1 Record/
Reprodua

1 FG Servocontrolled
DC Capstan;

1 DC Reel; 1 DC
ancillary

3-3/4 ips (9.5 cm/s) and
1-7/8 ips (4.8 cm/s)
21.0 16 deviation

:12 %

Approx, 85 seconds for
C-60

Less than 0.5 sec. to
reach standard Wow and
Flutter

500 x 401x 123 mm
(19-11/16 x 15-13/16"
x 4-13/16")

10.3 kg (22.7 lbs)

ELECTRICAL CHARACTERISTICS

MIXER SECTION

MIC/LINE Input
Input Impedance
Source Impedance
Nominal Input Level

Maximum Input Level
LINE B Input
Input Impedance
Nominal Input Level
Maximum Input Level
PGM Buss Input
Input Impedance
Nominal Input Level
Maximum Input Level
INSERTION
SEND (Tip)
Output Impedance
Nominal Load Impedance
Minimum Load Impedance
Nominal Output Level
Maximum Output Level
RECEIVE (Ring)
Input Impedance
Nominal Input LavaI
Maximum Input Level

100k ohms, unbalanced
Lessthan 10k ohms
>60dBVI1mVl.

MIC (Trim max.)

-10 dBV (0.3 V).

LINE (Trim min.)

+15 dBV (5.6 V)

28k ohms
-10 dBV (0.3 V)
+15 dBV (5.6 V)

22k ohms
-10 dBV (0.3 V)
+15 dBV (5.6 V)

1000th
10k ohms
1.7k ohms
-10dBV (0.3 V)
+15 dBV (5.6 V)

68k ohms
-10dBV (0.3 V)
+15dBV (5.6 VI

PGM/EFFECT/MONITOR Output

Output Impedance
Nominal Load Impedance
Minimum Load Impedance
Nominal Output Lavel
Maximum Output Lavel
HEADPHONES Output
Nominal Load Impedance
Maximum Output Level

100 ohms
10k ohms
1.7 kohms
-10dBV (0.3 V)
+15dBV (5.6 V)

8 ohms. stereophones
100 mW/ch. (8 ohms)