A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\MAINA.SCH Drawn By:

CMOD220p

RMOD390k

IN4148DMOD1

D41IN4004

D40IN4004

L1CHOKE

R3210k

R3110k

C154700u

C14

4700u

D5IN4004

D6IN4004

FS2T10A

FS1T10A

+15

-15

C2015p

C7100u

BOTTOM

WIPERTOP

C6100u

RV11k

-15

+15

C12deleted

C13deleted

C19100n

C18100n

C94p7

C54p7

C410p

C333p

C233p

C182p

R30560R

R29560R

R28560R

R27560R

R26560R

R25560R

R24560R

R23560R

R225k1

R215k1

R2039k

R1939k

R185k1

R175k1

R16150R

R15150R

R1410k

R1310k

R1268k

R111k

R36110k

R9120k

R810k

R7220R

R66k2

R53k3

R43k3

R310k

R23k3

R13k3

IC2NE5534

5

67

IC1BNE5532

3

21

84

IC1ANE5532

RV21k

C11100u

R1010k

C810u

C10100p

D2IN4148

D1IN4148

ZD19v1

ZD29v1

TR10BC184L

TR9BC214L

D3

IN4148

D4IN4148

TR1J162

TR2J162

TR3J162

TR4J162

TR5K1058 TR6

K1058TR7K1058

TR8K1058

-VE A

+VE A

R3510R

R10810R

R3410R

R3310R

C1647n

C1722n

RL1

D9IN4148

+15

RLY CNTRL

OP/A

OP/A 0V

OP/A MON

C/T A

BRIDGE OUT

I/P - A

I/P + A

I/P 0V

RL4

R1208k2

R1218k2

C61680p

C60680p

C7110p

C7010p

C6910p

C6810p

1kV

x2

SEE NOTE

SEE NOTE

2.5W

2.5W

2.5W 2.5W

2.5W

NOTECIRCUIT SHOWN APPLIES TO ST600

FOR ST400 TR4 & TR8 ARE NOT FITTED ANDR10 = 12kR19 & R20 = 30k

LMB3 4

3C1022ST 600/400 PCB

4

3

2

7

6

BIAS

CMRR

0dB Sensitivity Modification

Change R5 from 3k3 to 6k65Change R6 from 6k8 to 13k

A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\MAINB.SCH Drawn By:

C6410p

C6510p

C6610p

C6710p

RL4

R1238k2

C63680p

C62680p

R1228k2

BRIDGESTEREO

L2CHOKE

R6710k

R6810k

C384700u

C37

4700u

D14IN4004

D15IN4004

FS4T10A

FS3T10A

+15

-15

C2815p

C27100u

BOTTOM

WIPERTOP

C26100u

RV31k

-15

+15

C35Deleted

C36Deleted

C33100n

C31100n

C304p7

C254p7

C2410p

C2333p

C2233p

C2182p

R66560R

R65560R

R64560R

R63560R

R62560R

R61560R

R60560R

R59560R

R585k1

R575k1

R5639k

R5539k

R545k1

R535k1

R52150R

R51150R

R5010k

R4910k

R4768k

R481k

R45120k

R4410k

R43220R

R426k2

R413k3

R403k3

R3910k

R383k3

R373k3

IC4NE5534

RV41k

C34100u

R4610k

C2910u

C32100p

D11IN4148

D10IN4148

ZD39v1

ZD49v1

TR20BC184L

TR9BC214L

D12

IN4148

D13

IN4148

TR11J162

TR12J162

TR13J162

TR14J162

TR15K1058 TR16

K1058TR17K1058

TR18K1058

-VE B

+VE B

R6910R

R10910R

R7110R

R7010R

C3947n

C4022n

RL2

D18IN4148

+15

RLY CNTRL

OP/B

OP/B 0V

OP/A MON

C/T B

I/P - B

I/P + B

I/P 0V

D42IN4004

D43IN4004

3

21

84

IC3ANE5532

5

67

IC3BNE5532

DMOD21N4148

RMOD390k

CMOD220pBIAS

CMRR

INOUT

NOTECIRCUIT DIAGRAM SHOWN APPLIES TO ST600

FOR ST400 :TR14 & TR18 ARE NOT FITTEDR46 = 12kR55 & R56 = 30k

4

3

2

7

6

STi 600/400 PCBC1022 3

LMB2 4

4

8

SEE NOTE

SEE NOTE

2.5W

2.5W

2.5W

2.5W2.5Wx2

1kV

0dB Sensitivity Modification

Change R41 from 3k3 to 6k65Change R42 from 6k8 to 13k

A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\MAIN1.SCH Drawn By:

CIRCUIT SHOWN APPLIES TO THE ST600 VERSION

FOR THE ST400 R76 = 7k5

LIVE OUTLIVE IN

SG64

PEAK B

PEAK A

OV

+15

-15

R1063k

R1071k5

R11056R

C54100u

C53100u

C52470u

C51470u

D35IN4004

D34IN4004

D33IN4004

D31IN4004

Vin2

GN

D1

-15V 3

IC7MC7915T

Vin1

GN

D2

+15V 3

IC6MC7815T

-15

-15

ZD106V8

ZD96V8

C50100p

C45100p

TR22BC214L

TR21BC214L

+15

11

1013

IC5DLM339

R95470k

R96470k

R98470k

R101470k

R9710M R100

10M

C47470n C48

470n ZD712v

ZD812v

D26IN4148

D27IN4148

D29IN4148

-15

-15

+15

C4410u

D22 IN4148D24IN4148

D21IN4148

D20IN4148

ZD612v

ZD512v

C43470n

C42470n

R83220k

R84470k

R8110M

R7910M

R82470k

R80470k

R78470k

R77470k

-15

+15

C461uF

C411uF

D25IN4148

D19IN4148

R8947k

R904k7

R911M

R943k

R883k

R7518k

R7611k

R741MR73

4k7

R7247k

7

61

IC5BLM339

9

814

IC5CLM339

5

42

312

IC5ALM339MON A

O/P

MON BO/P

AC 118V

AC 2CON

FAN -

FAN +

POWER LED

BRIDGE SW2

BRIDGE SW1

BRIDGE LED

LED COMMON

0V

THERMAL/A

THERMAL A

RLY CONT A

RLY CONT B

o

N/C112 C

SEE NOTE

SOFT START

/

NOTE:

STi 600 / 400 PCBC1022 3

1 4LMB

A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\ST1000\C1048.S03 Drawn By:

C55A1n

C54A1n

FEEDBACK

+ MT

GT4A

SC2A

GT3A

SC1A

GT2A

ZD12A12V

ZD13A12V

C22A47p

C21A100n

R30A100R

R31A330R

R29A100k

R28A330R

R27A100k

D14ABAV21

D13ABAV21

C24A100p

C23A100p

C33A680p

C32A680p

D12ABAV21

D11ABAV21

D22AIN4148

D9AIN4148

R73A8k2

R71A82k

R70A82k

R67A8k2

R72A8k2

R69A2k7

R68A2k7

R66A8k2

GND

TR19ABC184L

TR18ABC214L

ZD11A12V

ZD10A12V

D2AIN4148

D1AIN4148

C31A100uF VR2A

1k

R65A150R

R64A150R

C30A100uF

C29A100uF

ZD8A15V

ZD9A15V

GND

GND

C14A100uF

R22A4k7

R17A3k3/5W

R21A1k5

C18A100uF

C15A100uF

ZD7A30V

ZD6A15V

ZD4A30V

ZD5A15V

C17A10p

R19A330k

3

21

84

IC1ANE5532

R23A10k

R20A120k

R16A330k

R18A680R

C13A100uF

BOTTOM

WIPER

5

67

IC1BNE5532 TOP

C12A100uF

R15A220R

C11A4p7

RV1A

R14A6k2

C10A10p

C9A33p

C8A33p

C7A82p

R13A3k3

R11A3k3

R12A10k

R9A3k3

R10A3k3

SCN

BLUE

RED

GT1A

R25A1k5

R24A4k7

R26A3k3/5W

C19A100uF

- MT

R80A30k

BRIDGE R85A2K2

C16A100uF

D25AIN4148

R83A100R

+15

-15

D26AIN4148

R84A100R

C52A47p

R82A33k

R81A33k

C53A680n

RV3A220k

FEEDBACK

C10483

1LMB

CHANNEL A DRIVER STAGE

OUT

+ MT

- MT

5

A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\ST1000\C1048.S04 Drawn By:

R84B100R

D26BIN4148

-15

+15

R83B100R

D25BIN4148

FEEDBACK

+ MT

GT4B

SC2B

GT3B

SC1B

GT2B

ZD12B12V

ZD13B12V

C22B47p

C21B100n

R30B100R

R31B330R

R29B100k

R28B330R

R27B100k

D14BBAV21

D13BBAV21

C24B100p

C23B100p

C33B680p

C32B680p

D12BBAV21

D11BBAV21

D22BIN4148

D21BIN4148

R73B8k2

R71B82k

R70B82k

R67B8k2

R72B8k2

R69B2k7

R68B2k7

R66B8k2

GND

TR19BBC184L

TR18BBC214L

ZD11B12V

ZD10B12V

D2BIN4148

D1BIN4148

C31B100uF VR2B

1k

R65B150R

R64B150R

C30B100uF

C29B100uF

ZD8B10V

ZD9B10V

GND

GND

C14B100uF

R22B4k7

R17B4k7

R21B1k5

C18B100uF

C15B100uF

ZD7B30V

ZD6B15V

ZD4B30V

ZD5B15V

C17B10p

3

21

84

IC1ANE5532

R23B10k

R20B120k

R18B680R

C13B100uF

BOTTOM

WIPER

5

67

IC1BNE5532

TOP

C12B100uFR15B

220R

C11B4p7

RV1B

R14B

6k2

C10B10p

C9B33p

C8B33p

C7B82p

R13B3k3

R11B3k3

R12B10k

R9B3k3

R10B3k3

SCN

BLUE

RED

GT1B

R25B1k5

R24B4k7

R26B4k7

C19B100uF

- MT

R80B36k

BRIDGE

C52B47p

C16B100u

C54B1n

C55B1n

R19B330k

R16B330k

R82B33k

R81B33k

C53B680n

RV3B220k

FEEDBACK

C10484

1LMB

STAGE

IN

+ MT

- MT

5

CHANNEL B DRIVER

A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\ST1000\C1048.S05 Drawn By:

DRAWING OF OUTPUT STAGE

COMPONENT REFERENCES SHOULD BE SUFFIXED WITH A OR B FOR RESPECTIVE CHANNELS

R772k2

R752k2

R47560R

R44560R

R45560R

R46560R

R40560R

R41560R

R42560R

R43560R

R36560R

R37560R

R38560R

R39560R

R32560R

R33560R

R34560R

R35560R

G

SD

TR13J162

G

SD

TR14J162

G

SD

TR15J162

G

SD

TR16J162

G

SD

TR9J162

G

SD

TR10J162

G

SD

TR11J162

G

SD

TR12J162

TR5K1058

TR6K1058

TR7K1058

TR8K1058

TR1K1058

TR2K1058

TR3K1058

TR4K1058

C4610P C47

10PC4810P

C4910P

C4210P

C4310P

C4410P

C4510P

C3810P

C3910P

C4010P

C4110P

C3410P

C3510P

C3610P

C3710P

D15BYT30P400

D16BYT30P400

R742K2

R762K2

R783R3

R793R3

C50100n

C51100n

C- MT

C- HTCON

C+ HT

C+ MT

GT2

GT3

SC1

SC2

GT1

GT4

5 5LMB

1C1048OUTPUT STAGE A/B

4W

4W

2.5W

2.5W4W

4WCmod2Cmod1

1 2 3 4 5 6 7 8

Title

Number RevisionSize

B

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\ST1000\C1048.S02 Drawn By:

ACL(B) ACL(B)

ACH(B) ACH(B)

- HT

- MT

+ MT

+ HT

RL1B

BR1BSB5006

BR2BSB5006

C1B9000uF

C2B9000uF

C3B9000uF

C4B9000uF

R1B2k2

R2B2k2

R3B2k2

R4B2k2

R5B10R R6B

10R

R8B10R

R7B10R

L1B

C5B220n

C6B100nC6A

100nC5A220n

L1A

R7A10R

R8A10RR6A

10R

R5A10R

R4A2k2

R3A2k2

R2A2k2

R1A2k2

C4A9000uF

C3A9000uF

C2A9000uF

C1A9000uF

BR2ASB5006

BR1ASB5006 RL1A

+ HT

+ MT

- MT

- HT

ACH(A)ACH(A)

ACL(A)ACL(A)

5

400V400V

2.5W2.5W

2.5W

2.5W

GND GND

OUTPUT B

C1048POWER SUPPLY SECTION

12

LMB

OUTPUT A

GNDGND

2.5W

2.5W2.5W

2.5W

400V400V

FEEDBACKFEEDBACK

A

B

C

D

E

F

Title

Number RevisionSize

A3

Date: 1-Jul-1999 Sheet of File: D:\PROTEL\ST\ST1000\C1048.S01 Drawn By:

7

61

IC1BLM339

D6BIN4148

D6AIN4148

+15

+15

21

RL1BRELAY

21

RL1ARELAY

THERMAL A

THERMAL/A

LED COMMONCN1.4

BRIDGE LEDCN1.5

BRIDGE SW1

BRIDGE SW2

POWER LEDCN1.3

FAN +

FAN -

AC 2CON

AC 118V

CHAN A

OUTPUT

5

42

312

IC1ALM339

R48A47k

R49A4k7

R50A1M

R51B11k

R55B18k

R52A3kD1A

IN4148

C25A1uF

+15

-15

R53A47k

R54A47k

R58A470k

R59A470k

R57A10M R60A

10M

R61B470kR56A

220k

C26A100u ZD1A

12v

ZD2A12v

D2AIN4148

D3AIN4148

D5AIN4148 D4A

IN4148

C27B10u

+15

-15

TR17ABC214L

C28A100p

ZD3A6V8

-15

Vin1

GN

D2

+15V 3

IC2MC7815T

Vin2

GN

D1

-15V 3

IC3MC7915T

D1IN4004

D2IN4004

D3IN4004

D4IN4004

C1470u

C2470u

C3100u

C4100u

R356R

R11k5

R23k

-15

+15

OV

PEAK A

CN1.1

NTC1

SG64LIVE IN LIVE OUT

PEAK B

CN1.2

-15

ZD3B6V8

C28B100p

TR17BBC214L

-15

D4BIN4148

D3BIN4148

D2BIN4148

ZD2B12v

ZD1B12v

C26B100u

R60B10M

R57B10M

R59B470k

R58B470k

R54B47k

R53B47k

C25B1uF

D1BIN4148

R52B3k

R50B1M

R49B4k7

R48B47k

CHAN B

OUTPUT

9

814

IC1CLM339

11

1013

IC1DLM339

+15

NTC2

SG64

+ MT

- MT

+ MT

- MT

LMB51

1C1048ST1000 PROTECTION

/

SOFT START

112 CN/C

o

/

(Y29)

(Y30)

(Y31)

CHANNEL B

CHANNEL A

ST Series Modification Procedure

General

The following changes are to be made to All ST amplifiers irrespective of Issue :

1) Remove C20 & C28 (10pF) from the PCB and replace with 15pF, 50V ceramic capacitors.2) Remove C10 & C32 (47pF) from the PCB and replace with 100pF, 50V ceramic

capacitors.3) Remove C17 & C40 (100nF) from the PCB and replace with 22nF, 250V polyester

capacitors.4) Remove C16 & C39 (220nF) from the PCB and replace with 47nF, 250V polyester

capacitors.5) Remove C12, C13, C35 & C36 from the PCB. Note, It is better to do this by cutting the

component leads close to the PCB to avoid damaging PCB traces.6) Fit 2 x 1N4148 diodes solder-side in reverse parallel from IC2 pin 3 to 0V, as per figure 1.7) Fit 2 x 1N4148 diodes solder-side in reverse parallel from IC4 pin 3 to 0V, as per figure 1.8) Remove any capacitors fitted on the solder-side of the PCB that connect to the middle pin

of the Output transistors. DO NOT remove the 10pF capacitors fitted across the twooutside pins of the K1058 transistors.

9) Fit 220pF, 1kV ceramic capacitors between Drain and Source of TR6 and TR17 as perfigure 1.

Issue Specific Changes

At this point, it is necessary to ascertain the exact issue status of the unit before proceeding,as follows:

1) Issue 6 PCBs: Go To Procedure 1.2) Issue 4 & 5 PCBs fitted with P1040 & P1041 protection daughter boards: Go To

Procedure 2.3) Issue 4 & 5 PCBs fitted with Resistor-Resistor-Diode-Capacitor networks in positions R55,

R56, R19 and R20: Go To Procedure 3.4) Previous Issues: Go To Procedure 4.

Procedure 1 Issue 6 PCBs

1) Remove R17, R22, R53 & R58 (5k6) from the PCB and replace with 5k1, 1/4W.2) Remove R18, R21, R54 & R57 (1k8) from the PCB and replace with 5k1, 1/4W.3) Remove ZD1, ZD2, ZD3 & ZD4 (12V) from the PCB and replace with 9V1 1/2W.4) Fit 390k, 1/4W resistor solder-side between D40 Cathode and D41 Anode, as per figure 2.5) Fit 390k, 1/4W resistor solder-side between D43 Cathode and D42 Anode, as per figure 2.

Procedure 2 Issue 4 & 5 PCBs with Modification Daughter Boards

1) Remove R17, R22, R53 & R58 (5k6) from the PCB and replace with 5k1, 1/4W.2) Remove ZD1, ZD2 & ZD3 (12V) from the PCB and replace with 9V1 1/2W.3) Fit 9V1, 1/2W zener diode solder-side in position ZD4 as per figure 3.

Modification to P1040 Daughter Board

1) Remove R18 & R21 (1k8) from the PCB and replace with 5k1, 1/4W.2) Fit 390k, 1/4W resistor solder-side between D1 Cathode and D2 Anode, as per figure 4.

Modification to P1041 Daughter Board

1) Remove R54 & R57 (1k8) from the PCB and replace with 5k1, 1/4W.2) Fit 390k, 1/4W resistor solder-side between D2 Cathode and D1 Anode, as per figure 4.

Figure 4

Procedure 3 Issue 4 & 5 PCBs with Resistor-Resistor-Diode-Capacitor Networks

1) Remove R17, R22, R53 & R58 (5k6) from the PCB and replace with 5k1, 1/4W.2) Remove R18, R21, R54 & R57 (1k8) from the PCB and replace with 5k1, 1/4W.3) Remove ZD1, ZD2, ZD3 & ZD4 (12V) from the PCB and replace with 9V1 1/2W.4) Fit 390k, 1/4W resistor between Component Network diodes as per figure 5.5) Fit 390k, 1/4W resistor between Component Network diodes as per figure 5.

Figure 5

Procedure 4

1) Remove R17, R22, R53 & R58 (5k6) from the PCB and replace with 5k1, 1/4W.2) Remove R18, R21, R54 & R57 (1k8) from the PCB and replace with 5k1, 1/4W.3) Remove ZD1, ZD2, ZD3 & ZD4 (12V) from the PCB and replace with 9V1 1/2W.4) Remove Components fitted in positions R19, R20, R55 & R56 and replace with networks

consisting of 1N4004 diodes, 8k2 resistors, 39k resistors, 680pF capacitors and 390kresistors as per figure 6.

5) Remove the fixing screws for the K1058 output transistors and remove the insulating padbetween the transistor and the heatsink.

6) Rub-down the heatsink with medium abrasive paper to remove any burrs or remnants ofinsulating pad.

7) Ensure the mounting faces of the power transistors are clean and then apply a thin, evenlayer of heatsink compound to the device and re-assemble the devices onto the heatsink.Ensure the fixing screws are secure but take care not to over-tighten.

Figure 6

General notes

Once the appropriate modifications have been carried out it is recommended that thefollowing checks are performed before attempting to re-test the amplifier.

1) Output Stage : Check for faulty Output transistors in the following way :a) Measure between Drain and Source of each transistor with a multi-meter set on a low

Ohms range. A short-circuit reading indicates one or more transistors is faulty.b) Measure between Gate and Source of each transistor with a multi-meter set on the 2k

Ohms range. A reading of less than 560 Ohms indicates a faulty transistor.

2) Zobel Resistors : Check R34, R35, R106, R69, R71 & R109. Replace with the correct10R, 2.5W parts if faulty, or show any signs of having over-heated.

Final Checks

Once the amplifier has been modified and repaired it is always possible that there remainsone or more components which have been weakened or damaged by any previous failure.The easiest way to confirm all is well is to perform a simple short-circuit test on the amplifieras follows : Drive the amplifier into a 4 Ohm load to an output level just prior to the clip point.Connect a short circuit across the amplifier output for a period of approximately ten seconds.Remove the short circuit and check the output returns to its previous level. If any Outputtransistors fail during this test, they should be replaced, but output transistors continue to fail(especially if they are recently replaced parts) the current limiting protection circuits should bechecked for faulty components.