Akai UniBass UB1 User manual

SERVICE MANUAL 1
UB1
Functions: ......................... SELECT - ADD LOWER 4TH, SOLO, ADD UPPER 5TH SWITCH MODE - LATCH,
UN LATCH
Connectors: ...................... INPUT (Input impedance: 500k ohms or more)
MIX (Output impedance: 1k ohms or less)
EFFECT (Output impedance: 1k ohms or less)
DC IN (9 Volts)
Controls:............................ INPUT LEVEL, TONE, DISTORTION, OUTPUT LEVEL, NOISE GATE THRESHOLD,
SWITCH MODE, SELECT, FOOTSWITCH (EFFECT on/off, MODIFY on/off) x 2
Indicator: ........................... LED x3 (Input Level)
LED x2 (Effect on/off, MODIFY on/off)
Power requirements: ........ 9V DC/140mA, AC adaptor MP-9
Accessories: ..................... Operator’s Manual, AC adaptor MP-9
Dimensions: ...................... 140 (W) x 175 (D) x 61 (H)mm
Weight:............................... 720g
• Specifications are subject to change without notice.
Harmonized Bass Distortion
MODEL UNIBASS UB1
SPECIFICATIONS

SERVICE MANUAL
2
##
##
#SAFETY INSTRUCTIONS ##
##
#INFORMATIONS
SYMBOLS FOR PRIMARY DESTINATION
Unit destinations are indicated with letters as shown below.
Symbols Principal Destinations
A U.S.A
BU.K
C Canada
E Europe (except U.K)
J Japan
S Australia
V Germany
U Universal Area
Y* Custom version
1. Parts identified by the }symbol are critical for safety.
Replace them only with the parts number specified.
2. In addition to safety, other parts and assemblies are
specified for conformance with such regulations as those
applying to spurious radiation.
These must also be replaced only with the specified
replacements.
Examples : RF converters, tuner units, antenna selector
switches, RF cables, noise blocking capacitors,
noise blocking filters, etc.
3. Use specified internal wiring. Note especially :
1) Wires covered with PVC tubing
2) Double insulated wires
3) High voltage leads
4. Use specified insulating materials for hazardous live parts.
Note especially :
1) Insulation Tape
2) PVC tubing
3) Spacers (insulating barriers)
4) Insulation sheets for transistors
5) Plastic screws for fixing micro switches
5. When replacing AC primary side components (trans-
formers, power cords, noise blocking capacitors, etc.), wrap
the ends of the wires securely around the terminals before
soldering.
6. Make sure that wires do not contact heat producing parts
(heat sinks, oxide metal film resistors, fusible resistors,
etc.).
7. Check that replaced wires do not contact sharp edged or
pointed parts.
8. Also check areas surrounding repaired locations.
9. Make sure that foreign objects (screws, solder droplets,
etc.) do not remain inside the set.
SAFETY CHECK AFTER SERVICING
After servicing, make measurements of leakage-current or
resistance in order to determine that exposed parts are
acceptably insulated from the supply circuit.The leakage-
current measurement should be done between accessible
metal parts (such as chassis, ground terminal, microphone
jacks,signalinput/outputconnectors, etc.)and theearthground
through a resistor of 1500 ohms paralleled with a 0.15 µF
capacitor, under the unit’s normal working conditions.
The leakage-current should be less than 0.5 mA rms AC.The
resistance measurement should be done between accessible
exposed metal parts and power cord plug prongs with the
power switch (if included) “ON”. The resistance should be
more than 2.2 M ohms.

SERVICE MANUAL 3
SUPPLEMENTARY INFORMATION
About the UB1 test mode
This test mode is used to confirm operations from the SWITCH MODE and SELECT switches up to the micro
computer (IC4 HD6433641RB15H).
Test mode operation
While pressing down on both foot switches, turn on the power. (Plug in the DC power plug). All LEDs will flash 4
times and the test mode will then be engaged.
Points to be confirmed
SWITCH MODE
LATCH: Confirm that the ON/OFF LED lights (red)
UNLATCH: Confirm that the MODIFY LED lights (green)
SELECT
ADD LOWER 4th: Confirm that the INPUT LEVEL LED lights (green)
SOLO: Confirm that the INPUT LEVEL LED lights (yellow)
ADD UPPER 5th: Confirm that the INPUT LEVEL LED lights (red)
• To cancel the test mode, unplug the DC power plug.

DCIN
SELECT
SWITCH MODE
OUTPUT
LEVEL
DISTORTION
NOISE GATE
THRESHOLD
INPUT
LEVEL
TONE
UB1
SCHEMATIC DIAGRAM
MODIFY
ON/OFF
4

5

SERVICE MANUAL
6
PARTS LIST
HOW TO USE THIS PARTS LIST
1. This Parts List lists those parts which are considered necessary for repairs.
2. Parts not shown in the Parts List will not in principle be supplied.
3. How to read the Parts List.
The available PC Board Blocks are listed separately.
WARNING
}}
}}
}INDICATES SAFETY CRITICAL COMPONENTS. FOR CONTINUED SAFETY, REPLACE SAFETY CRITICAL
COMPONENTS ONLY WITH MANUFACTURER'S RECOMMENDED PARTS.
AVERTISSEMENT
}}
}}
}IL INDIQUE LES COMPOSANTS CRITIQUES DE SÉCURITÉ. POUR MAINTENIR LE DEGRÉ DE SÉCURITÉDE
L'APPAREIL, NE REMPLACER QUE DES PIÉCES RECOMMANDEES PAR LÉ FABRICANT.
ATTENTION
1. When placing an order for parts, be sure to list the Part No., Model No. and the description of each part.
Otherwise, the non-delivery of the part or the delivery of a wrong part may result.
2. Please make sure that Part No. is correct when ordering.
If not, a part different from the one you ordered may be delivered.
3. Since the parts shown in Parts List or Preliminary Service Manual may have been the subject of changes,
please use this Parts List for all future reference.
Symbols for primary destination
[A] : AAL (U.S.A) [S] : SAA (Australia)
[B] : BEAB (England) [U] : U/T (Universal Area)
[C]: CSA (Canada)
[E] : CEE (Europe) [V] : VDE (Germany)
[J] : JPN (Japan) [Y] : Custom
SP (Service Parts) Classification
These reference symbols correspond with
component symbols in the Schematic
Diagrams.
a) Mechanism Block
2.HEAD BASE BLOCK
SP (Service Parts) Classification
This number corresponds with the indi-
vidual parts index number in the figure.
Ref. No. Part. No. Description
1 BH-T2023A320A HEAD BASE BLOCK
2 HP-H2206A010A HEAD R/P PR4-8FU C
3 ZS-477876 PAN20↔03STL CMT
4 ZS-536488 BID20↔08STL CMT
5 ZG-402895 SP CS ANGLE ADJUST
b) PC Board
2.MAIN PC BOARD
Ref. No. Part. No. Description
IC1 EI-324536 IC HD14049BP
IC2 EI-336801 IC MB8841-564M
C1A EC-338399 C MMY V 223M 250AC [U,E,B,S]
C1B EC-350949 C MMY V 223M 250DC [J]
C1C EC-338397 C MMY V 223M 125AC [C,A]
X1 EI-318384 OSC X'TAL NC-18C

SERVICE MANUAL 7
1. PC BOARD BLK UB1
Ref. No. Part No. Description
1 BA-L8012A020A PC(#) UB1 BLK UB1
PC(#)UB1BLKCONSISTSOF FOLLOWINGPCBOARDS
•PC MAIN BLK UB1
•PC OPERATION BLK UB1
2. PC MAIN BLK UB1
Ref. No. Part No. Description
IC1 EI-438318J IC NJM78L05AT1 T05
IC2 EI-438318J IC NJM78L05AT1 T05
IC3 EI-431113J IC M51953BFP-73A FP73AT12E
IC4 EI-813210J IC HD6433641RB15H UB1
IC5 EI-811878J IC AK7712AVT
IC6 EI-812883J IC HM6264BLFP-8LT
IC11 EI-813022J IC NJU7032M FPT1T08
IC12 EI-403306J IC NJM4558L
IC13 EI-403306J IC NJM4558L
J1 }EJ-812072J SOCKET DC HTJ-020-05A 1P
J2 EJ-812069J PHONE J HTJ-064-13H 6.3
J3 EJ-812069J PHONE J HTJ-064-13H 6.3
J4 EJ-812069J PHONE J HTJ-064-13H 6.3
TR1 ET-842477J TR FET 2SK2880 C,D,E T05
TR2 ET-362847 TR 2SA1317 S,T,U T05
TR3 ET-362198 TR 2SC3330 R,S,T,U,V T05
TR4 ET-362847 TR 2SA1317 S,T,U T05
TR5 ET-394735J TR 2SC3792 T05
X1 EI-812885J OSC X’TAL HC-49/U 10000KHz
X2 EI-811908J OSC X’TAL HC-49/U 18432KHz
2. PC OPERATION BLK UB1
Ref. No. Part No. Description
D1 ED-386225J D SILICON 1N4002 T26 100/1.0A
D2 ED-811455J D SILICON H 1SS133T-77 T26
D10 ED-811455J D SILICON H 1SS133T-77 T26
100 SE-812673J SPACER LED L=12
200 SE-812672J SPACER LED L=8.5
D201 ED-812086J D LED L-934SGD GREEN
D202 ED-813021J D LED L-934SYD YELLOW
D203 ED-812087J D LED L-934SRD-G RED
D204 ED-812087J D LED L-934SRD-G RED
D205 ED-812086J D LED L-934SGD GREEN
SW201 ES-812125J SW SLIDE SSSS913Z-4C2-0* 01-03
SW202 ES-812886J SW SLIDE SSSS912N-4C2-0* 01-02
TR201 ET-842477J TR FET 2SK2880 C,D,E T05
VR201 EV-812076J VR ROTARY RK09L1140 L12.5 B103
VR202 EV-812076J VR ROTARY RK09L1140 L12.5 B103
VR203 EV-812076J VR ROTARY RK09L1140 L12.5 B103
VR204 EV-812076J VR ROTARY RK09L1140 L12.5 B103
VR205 EV-812887J VR ROTARY RK09L1140 L12.5 A104
2. PC FINAL ASSEMBLY BLK UB1
Ref. No. Part No. Description
1 SP-812829J PANEL MAIN UB1
2 SK-812205J KNOB SLIDE
3 SM-812280J MASK KNOB
4 ES-812893J SW PUSH SB-221(METAL) 01-01
5 ZW-812439J SW120STL CMT
6 ZW-812440J PW122X160X050STL NI3
7 ZS-376521 BT BID30X08STL CMT
8 SP-812211J COVER BOTTOM (A)
9 SA-812237J FOOT
10 SK-812204J KNOB VOL
11-A }AX-812121X2 AC ADAPTER L8006 J (PLUG IN)
[J]
11-B }AX-812122X2 AC ADAPTER L8006 C,A (PLUG IN)
[A]
12 }AX-812123X2 AC ADAPTER L8006 E,V (CORD IN)
[E,V,B]
13 }EJ-428247N PLUG ADAPTOR ECPL01BKR5
BS5733 [B]

SERVICE MANUAL
8
FINAL ASSEMBLY BLK UB1
12
9
7
9
7
9
7
13
11
8
7
7
5
4
6
1
10
3
2

SERVICE MANUAL 9
1-3, Hiranuma 1-Chome, Nishi-Ku, Yokohama, Japan
SERVICE SECT. PHONE : [phone] FAX : [phone]
Printed Date : Oct 6, 2000
Printed in Japan
ABBREVIATIONS FORTHE SERVICE MANUAL
ABBREVIATION EXPLANATION ABBREVIATION EXPLANATION
MINI MINImum
MIX MIXer
MOD MODulation / MODulator
M.WHEEL Modulation WHEEL
OSC OSCillator
PLD Programmable Logic Device
RAM Random Access Memory
RD ReaD
REG REGulator
RESO RESOnance
RL ReLay
ROM Read Only Memory
SCSI Small Computer System Interface
S/H Sample and Hold
SIMM Single Inline Memory Module
SMPTE Society of Motion Picture & Television
Engineers
SW SWitch
THRU THRoUgh
TRANS TRANSpose
U Upper
VA Voltage Analog
VCA Voltage Controlled Amplifier
VCF Voltage Controlled Filter
VR Variable Resistor
VREF REFerence Voltage
WR WRite
AMP (Amp) AMPlifier
BBD Backet Brigade Diode
BCD Binary Code Decimal
B.DOWN Brake DOWN
B.UP Back UP
CE Chip Enable
CH CHannel
COMP COMParator
CONT CONTrol
CV Control Voltage
D/A Digital to Analogue
DIR DIRectory
DMA Direct Memory Access
DSP Digital Signal Processor
EG Envelope Generator
EXT EXTernal
FREQ FREQuency
HPF High Pass Filter
INH INHibit
INT INTerrupt
INV INVerter
LLower
LAN Local Area Network
LFO Low Frequency Oscillator
MAX MAXimum
MEMO MEMOry
MIDI Musical Instrument Digital Interface