Tascam Porta One Ministudio Service Manual

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TASCAM

TEAC Professional Division

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SERVICE MANUAL

MINISTUDIO
PORTA ONE

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$99} $8.2m; mm
55% WEB/MN My ' I
.- 5§,_EARI$-.~ mug, 2:139 a

/ Effective: December, 1984 5704023200

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MINISTIDIO
PORTA ODE
CONTENTS
1. SPECIFICATIONS AND SERVICE DATA ............................................... 3
2. FEATURES AND CONTROLS ...................................................... 4
3. CIRCUIT DESCRIPTION .......................................................... 13
3-1 Genera! ................................................................ 13
3-2 Control Circuit ........................................................... 15
3-3 Power Supply Circuit (Power Mute Circuit) ........................................ 17
34 Mixer Circuit ............................................................ 18
3-5 Record and Playback Circuit .................................................. 20
4. MAJOR PARTS LOCATION ............. , 24
5. MAIN MAINTENANCE EQUIPMENTS ................................................ 25
6. MEASUREMENT CONDITIONS FOR MAINTENANCE .................................... 26
7. REMOVAL OF MAJOR PARTS .................................................... 27
8. MECHANICAL CHECKS AND ADJUSTMENTS ........................................ I. . 28
8-1 Capstan Assembly Thrust .................................................... 28
8-2 Pinch Roller Pressure ....................................................... 28
8-3 Take-up Torque .................................... . ..................... 28
84 Tape Travel ............................................................. 29
8-5 Head Azimuth ............................................................ 29
8-6 Tape Speed ............................................................. 29
8-7 Wow and Flutter .......................................................... 30
9. MIXIER SECTION SIGNAL CHECKS AND ADJUSTMENTS ................................. 30
10. RECORD/PLAYBACK AMPLIFIER CHARACTERISTICS ............................. ...... 32
10-1 Playback Level ........................................................... '33
10-2 Playback Frequency Response ..................................... ' ............ 33.
10-3 Dummy Coils ............................................................ 33
10-4 Bias Trap ............................................................... 33
10-5 Bias Voltage ............................................................. 34
10-6 Record Level ............................................................ 34
10-7 Overall Frequency Response .................................................. 34
10-8 Overall Distortion ......................................................... 34
109 Overall SN Ratio .......................................................... 35
10-10 Erasing Ratio ............................................................ 35
10-11 Crosstalk Between Channels .......................... h; ..................... 35
10-12 Sync Crosstalk .................................. '. f:'-. ..................... 35
10-13 Voltage of DBX Amplifiers ................................................... 35
11. EXPLODED VIEW AND PARTS LIST ................................................ 36
12. IC INTERNAL CIRCUIT ......................................................... 44
13. PC. BOARDS AND PARTS LIST ................................................... 45
R/P Ampl. P.C.B. Assy, Control P.C.B. Ass'y
Mixing Ampl. P.C.B. Assy, Tape Cue Ampl. P.C.B. Ass'y, Switch P.C.B. Ass'y
Schematic Diagrams ............................................................ Attached