Romal RB-981 Service manual

Quality Uncompromised

Wiring Diagram

®

Technical

Manual

Table of Contents

Specification.....................................1

Wiring Diagram ................................2

Parts List ..........................................3

Adjustment .......................................4

PCB Assembly .................................5,6

Schematic Diagram..........................7,8

Specification

STEREO POWER AMPLIFIER

RB-981

Continuous Power Output (20-20 kHz, ≤ 0.03%, 8 ohms) 130 watts/ch.
(20-20 kHz, ≤ 0.05%, 4 ohms) 170 watts/ch.
Bridged Mono Power Output (20-20 kHz, ≤ 0.1% THD, 8 ohms) 360 watts
Total Harmonic Distortion (20 Hz-20 kHz, 8 ohms) ≤ 0.03%
Intermodulation Distortion (60 Hz : 7 kHz, 4:1) ≤ 0.03%
Frequency Response 10-100,000 Hz,±1 dB
Damping Factor (20-20,000 Hz, 8 ohms) 500
Speaker Impedance (Normal mode) 4 ohms minimum
(Bridged mode) 8 ohms minimum
Signal to Noise Ratio (IHF A network) 120 dB
Input Impedance/Sensitivity 33 k Ohms/1.0 volt
Power Requirements 115 Volts, 60 Hz or
230 Volts, 50 Hz
Power Consumption 400 Watts
Dimensions (W, H, D) 440 x 121 x 327 mm

17.38 x 4.76 x 12.87"
Weight(net) 10.3 kg., 22.66 lb.

BUNZAN-SHINSEN-BLD. 4F 10-10 SHINSEN-CHO, SHIBUYA-KU,
TOKYO 150-0045, JAPAN

Serial. NO.
Begining

2

Parts List Adjustment

SYMBOL PARTS NO. DESCRIPTION SYMBOL PARTS NO. DESCRIPTION

X–1240–01 PCB ASSEMBLY

C601,602 041 50BGF4R7M
C603,604 044 TFKP2–100V681H
C605,606 044 LFSC160V221H
C607,608 041 25BGF100M
C609,610 044 LFSCl60V331H

C611,612 041 50BGF10M
C613–616 044 LFSC160V561H
C617,618 044 LFSC160V471H
C623,624 044 MKT18–100V104K
C802 041 GS25V101–B

C803 041 GS63V221–D
C804 041 GS63V220–B
C901–908 043 LTC500V103
C909–912 041 ALC20S1023XX
D601–608 034 LT1N4148–86

CAP, ELEC. 50V4. 7UF
CAP, FILM 100V680PF
CAP, STYROL 160V220PF
CAP, ELEC. 25V100UF
CAP, STYROL 160V330PF

CAP, ELEC. 50V10UF
CAP, STYROL 160V560PF
CAP, STYROL 160V470PF
CAP, FILM 100V0. 1UF
CAP, ELEC. 25V100UF

CAP, ELEC. 63V220UF
CAP, ELEC. 63V22UF
CAP, CERA. 500V0. 01UF
CAP. ELEC. 63V10000UF
DIODE

R661 054 LTMK2018KFECZ
R801 054 1WS2. 7KJF
R802 053 CR14–101J–A
R803 053 CR14–104J–A
R804 053 CR14–224J–A

R805 053 CR14–104J–A
R806 053 CR14–333J–A
R807 053 CR14–104J–A
R808 053 CR14–272J–A
R809, 810 054 1WS6. 8KJF

R811, 812 053 CR14–104J–A
R813, 814 053 CR14–183J–A
R815, 816 053 CR14–392J–A
R817, 818 053 CR14–273J–A
R819 054 1WS6. 8KJF

R, METAL 1% 18K
R, METAL 1W 2.7K
R, CARBON 100R
R, CARBON 100K
R, CARBON 220K

R, CARBON 100K
R. CARBON 33K
R. CARBON 100K
R, CARBON 2.7K
R, METAL 1W 6.8K

R, CARBON 100K
R, CARBON 18K
R, CARBON 3.9K
R, CARBON 27K
R, METAL 1W 6.8K

Instruments : DC milli–voltmeter
Notes : Prior to Bias Adjustment, run about 5minutes with rated output(8ohms) and

Step

Plus Lead

1

2

warm up Power Transistor and Heat Sink. Set input off.

Coupling

Location Adjust Adjust for

Minus Lead

TP1–1

TP2–1

TP1–2

TP2–2

X–1240–01 PCB

X–1240–01 PCB

VR601

VR602

DC milli–voltmeter reads 5mV

D609–612 034 LT1N4003–TB
D80l 034 LT1N4148–86
D802 034 TRD6. 2JST1
D803–806 034 LT1N4003–TB
D807,808 034 LT1N4148–86

D901,902 034 LBR84
F601–604 036 5ST5
PJ1 066 L4TR–2487#8
PJ2 066 L4TR–2487#7
Q601–606 033 LT2SC2362KAA–FG

Q607–612 033 LT2SA1016KAA–FG
Q613,614 033 L2SA1209–ST
Q615,616 033 L2SC2911–ST
Q619,620 033 T2SC3478T–LKU
Q621,622 033 T2SA1376T–LKU

Q801–803 033 LT2SC2362KAA–FG
R601,602 054 LEE10–102
R603,604 054 LEE10–333
R605,606 054 LEE10–471
R607–610 054 LTMK201K5FECZ
R611,612 054 LTMK2220RFECZ

R613,614 054 LTMF1/4–5600F
R615–618 054 LTMK201K5FECZ
R619,620 054 LTMK2220RFECZ
R621,622 054 LTMK2047KFECZ
R623,624 054 LTMK2100RFECZ

DIODE
DIODE
ZENER DIODE
DIODE
DIODE

POWER DIODE
MINI FUSE 250V5A
1P PIN JACK(WHT)
1P PIN JACK(RED)
TRANSISTOR

TRANSISTOR
TRANSISTOR
TRANSISTOR
TRANSISTOR
TRANSISTOR

TRANSISTOR
R, METAL 1K
R, METAL 33K
R, METAL 470R
R, METAL 1% l. 5K
R, METAL l% 220R

R, MRS25 560R
R, METAL l% l. 5K
R, METAL 1% 220R
R. METAL l% 47K
R, METAL 1% 100R

RY801 063 EG2–24NU
S601–603 068 TD–03SG
SP1 067 C–4493A00
TH601, 602 034 TD5C350D
VR601, 602 051 LVM6CKPV1S2.2K

019 TO–126
069 C–3417A

X–1240–02 PCB ASSEMBLY

C001 044 DE7150F472M
S00l 061 LC–4176A02

HEAT SINKER ASSEMBLY

Q617, 618 032 2SD1953
Q623, 624 033 2SC4381–OY
Q625, 626 033 2SA1667–OY

Q627–632 033 2SC3856 –OPY
Q635 –640 033 2SA1492–OPY
019 TO–220

019 TO–3P
017 RM4–08B00

OTHERS

011 TFP–801A
012 L4TQF–15
014 C–4550A13
014 L4TR–2797#3
014 RM4–07A00

RELAY
3P CONNECTOR WAFER
SPEAKER TERMINAL
THERMISTER
SEMI–FIXED RESISTOR

INSULATION SHEET
FUSE CLIP

SPARK KILLER
POWER SWITCH

TRANSISTOR
TRANSISTOR
TRANSISTOR

POWER TRANSISTOR
POWER TRANSISTOR
INSULATION SHEET(S)
INSULATION SHEET(L)
HEAT SINKER BOARD

FRONT PANEL ASSY
POWER BUTTON 14X14
UPPER COVER
ORNAMENT SIDE BOARD
BOTTOM BOARD

E

C

B

2SA1376
2SC3478
2SA1209
2SC2911
2SA1016K
2SC2362K

B

C

E

2SA1667
2SC4381

E

C

B

2SD1953 2SA1492

B

C

2SC3856

E

R625,626 054 LTMF1/4–6801F
R627,628 054 LTMF1/4–3901F
R629,630 054 LTMK2100RFECZ
R631,632 054 LTMK2001KFECZ
R633,634 054 LTMK2047RFECZ

R635–646 054 NIR2–0. 22JF
R647,648 054 2WS10JF
R651,652 054 LTMK2018KFECZ
R653,654 054 LTMF3300
R655–658 054 LTMK2220RFECZ

R, MRS25 6. 8K
R, MRS25 3. 9K
R, METAL l% 100R
R, METAL l% 1K
R, METAL l% 47R

R, METAL 2W 0.22R
R, METAL 2W 10R
R, METAL l% 18K
R, METAL 330R
R, METAL 1% 220R

015 RP–334
019 L4TSH–19#2
019 4TR–2823#2
022 T–1052W04
072 L4TR–670#5

072 LC–3763
072 C–4572A0l
072 C–4573A01
081 LTZ–183
081 RM4–11B00

REAR CHASSlS
PLASTIC FOOT 50F
PLASTIC FOOT 24F
POWER TRANSFORMER
AC CORD for STD

AC CORD for AUSTRALIA
AC CORD for UK
AC CORD for CEE
STYROL SIDE MOULDING
INSIDE CARTON

43