Brüel & Kjær 2210 Service Instruction

Brilel

&

Kjcer

037

-

0288

2210

Impulse Precision

Sound Level

Meter

Valid from serial no.

65

98

67

. .

...

·-

.

; f •

,.

Brliei&Kjmr

037

-

0288

2210

Impulse Precision

Sound Level

Meter

Valid

from

serial no.

65

98

67

. '

BROEL

&

KJJ.'ER

Ncerum -

Denmark

037

-

0288

8.78

Service

Instruction

2210

Impulse Precision

Sound Level

Meter

Valid

from

serial no.

65

98

67

RHODE~

-G;1QOS

lABORATORIES,

lNC.

3409

ANDTREE

BLVD.

AUSUN,

TEXAS

78724

2210

0-1

Service Instruction

2210

consisting

of:

page

Service Instruction

0-1

0-2

0-3

0-4

Checking Procedure

1-1

1-2

1-3

Power Supply

2- 1

Preamp. and Log Peak Detector

3-1

3-2

3-3

VCA and

Weighting

Network

4-1

4-2

4-3

4-4

LMS

and Hold Circuit

5-1

5-2

5- 3

5-4

5-5

Logic and Display Circuit

6-1

6-2

6-3

Input

Stage,

ZC

0007

Logic Control,

ZD

0146

Counter Decoder,

ZD

0147

Preamp

./

Ref. Generator,

ZE

0199

/

0Z

0014

Hold Circuit/

Working

Range Detector,

ZE

0200

Weighting

Networks/ AC-DC Buffers,

ZE

0201

/

OE

0151

Power Supply/ Analog

to

Pulse Train Converter,

ZG

0124

1

2

VCA/ LPD,

ZH

0128

LMS

Detector,

ZL

0053

Recorder Connector,

ZN

0176

·

Output

Driver,

ZN

0177

Mechanical Parts

7-1

7-2

Block Diagram

with

Parts List

8-1

0-2

date

8.

78

8.

78

8.

78

8.78

8.

78

8.

78

8.78

8.

78

8.

78

8.

78

8.

78

8.78

8.

78

8.

78

8.78

8.

78

8.

78

8.78

8.

78

8.78

3.

78

3.78

3.

78

3.

78

3.

78

3.78

3.

78

3.

78

3.

78

3.78

3.

78

3.

78

8.78

3.

78

Spare

Parts

Please

state type and serial

number

of

the

instrument

when

ordering

spare parts.

Trouble

Shooting

If any.

fault

should occur, check

the

instrument

according

to

the

Checking

Procedure.

The Checking Procedure is divided up

into

sections,

where

each section

will

refer

to

a subsection in

the

Service

Instruction

corresponding

to

a

specific part

of

the

instrument.

The subsection in

the

Service

Instruction

will

normally

consist

of

a Block

Diagram, a Technical Description, an

Adjustment

Procedure and a

Simpli-

fied Diagram

where

the

test

points are identified.

Before correction any apparent deviation make

sure

that

the

measuring

instrument

has tolerances small enough

not

to

affect

the

measurement.

When

a

fault

has been traced and corrected,

the

voltages and adjust-

ments influenced by

the

correction

must

be rechecked. The complete

in-

strument

should

then

be tested

to

make

sure

that

all basic

functions

are

operative.

The tolerances given

in

these notes are intended

for

use as guide

for

ad-

justments

.

Updating

Due

to

the constant progress in technology

the

instrument

will

from

time

to

time

be brought up to date

in

order

to

provide

continuously

improved

performance.

For

this

reason there may be small variations between

the

instrument

and the Service Instruction.

However,

the local Service Representative is in possession

of

all

informa-

tions regarding any change

that

has been made.

8.

78

8.78

Weightinf

NetwOrtc

Briiel&

K;.t'

M~er~

Sensitivity

Correction

AC

Monitor

Type

2210

Impulse

Precision

Sound

level

Meter

Valid

from

serial no.

65

98

67

Service

Instruction

2210

0-3

2210

Service

Instruction

----.---.

----

·

-------

.

----·

---.

---.-------

-

-----

·

---·---·----

VCA

I

nput

VCA

Output

logarithmic

Peak

Detector

Pr~:>ampliti~:>r

and

lag

PI:'Ok

Oet~:>clor

-+---

-

...2QQd_;

Ex

I.

Filler

AC

Output

To

----.

---

·

---

.

---

.

----

---

·

---

·

--~-

VCA

Buttu

Buft~:>r

to

Top!'

RI:'C

.

14

'

15

\

R~:>cord~:>r

Conn~:>ctor

fr

om

Tap<>

R~:>c.

Ll:'

v

el

Input

[

Networks

lOdB

Amp

.

VCA

and

Weighting

N~:>lwork

2210,4

AC

Output

~-

·

----

--1----

·---

.

----

·

----

-

---

.

--.

AC

Input

Lev~:>llnpul

I

LPO

Output

I

',

__

---

~~----

_

_!.~

!l_l'!:_l

S!:'lector

Hie.

Sense

Correc

lion

LMS

and

Hold

Circu~

·

t

1210,5

----

.

---

.

---.

----.

---.

---

.

t---t-

Analoqut>

IIIII

1!!1

IIIII

'"'"'

l

l~:>vel

Pulse

Train

0-4

+-----·

---

.

----

----·---·

Error

Ceunter/

Ot>coder

----

·

---·

----

,-, ,-,

II

!_/OLIO

.

----·

~··~·.~

8.78

BROEL

&

KJ~R

Nrerum

-

Denmark

1 .

1.

Electrical

Calibration

REF

. 1:

"In"

INPUT LEVEL:

"Low"

GAIN CONTROL MODE:

"Auto"

LMS

DETECTOR

:

"Fast"

READOUT CONTROL: "Clock"

EXT.

FILTER

: "

Out

"

WEIGHTING SELECTOR:

"Lin."

REC

./

PLA YBACK: "Recording"

(Located on the left hand side

of

the

221 0)

REF

. 1. to

"Out"

LMS

DETECTOR

to

"Slow"

dB

+ 1

0

10

8.78

+0

,5

Checking Procedure

2210.1

31.

6

Check the

Meter

deflection: Approx.

-1

6 dB.

If no deflection consult

the

Preamplifier and

Log

Peak Detector

2210

.3.

Check the

voltage at "To Ext.

Filter"

: 1 V RMS

Check the voltaQe at

"AC

Output

":

3.

16

V RMS.

If

this

voltage is not correct consult the VCA and

Weighting

Network

2210

.4.

Check the

voltage at

"DC

Output"

:

4200

mV.

If

necessary adjust

REF

. 1.

Press

REF

. 2 and activate

RESET

.

Check the

voltage at

"DC

Output

":

2200

mV.

If

necessary adjust

REF.

2.

The adjustment of

REF.

and

REF

. 2 should be repeated

until

the

reading is exactly

4200

mV and

2200

mV.

If

the voltages

for

REF

. 1 and

REF

. 2 cannot

be

obtained consult

the

LMS and Hold Circuit

2210

.5.

Check the reading on the

Display:

84

,0 and

44,0

respectively.

If

the Display reading is not correct consult the Logic and Display

2210

.6.

Activate

MIC. SENS .

CORR

. and adjust MIC. SENS. CORR. potm:

to

O,OdB correction

when

REF

.':1' is pushed in.

Note

In order to proceed

with

the

Checking Procedure

it

is imperative

that

the above mentioned ad-

justment

of

REF

. 1.

REF

. 2 and

the

MIC. SENS. CORR. is correct.

In order to obtain the correct results of

the

following

measurements the signal

must

be ap-

plied to

the

221 0 via an Adaptor

JJ

2614

Input Signal:

50mV

251,2Hz

.

Check the

Display reading:

94,0

± 0,1 dB.

Check the frequency response according to

the

table

below

.

+

0.3

-0

.3

251.2

Ref

.

+0,2

o.z

1 k

+

0.3

-o.3

-0

,7

4k

Bk

20

k

Frequency

in

·

Hz

If the Display reading is out of tolerance consult

the

VCA and

Weighting

Network Section

221

0.4.

Check the

Meter

reading: Approx.

-6

dB.

If

the

meter is

off

consult the Preamplifier and Log. Peak Detector

2210

.3.

Decrease the

Input

Signal to give a Display reading

of

84,0

dB

.

Check

the Linearity of the Dynamic Range in 1 0 dB increments.

Tolerance±

0.4dB

. Ref.

84

,

0dB

.

If

the Linearity is

out

of tolerance consult the VCA and

Weighting

Network

2210

.4.

Note:

In order

to

maintain

a

sufficient

accuracy

it

is suggested

to

use a Precision

Attenuator

having an accuracy of 0,

05

dB

or

better.

Valid from serial no.

65

98

67

1-1

Checking Procedure

221

Q. 1

INPUT LEVEL

to

"

Mad

."

INPUT LEVEL

to

"Hi9h"

GAIN CONTROL MOOE

to

"Mrs~\

.

"

MANUAL

GAIN

CONTRCX.

to "MIP."

WEIGHTING

SELECTOPI

to

"A"

LMS

DETECTOR to

"Imp

."

,_2

Adjust

the

Input Signal (at 1 kHz) to give a Display reading of

84

,0 dB

Check the Display reading:

84

dB ± 0,1 dB

Check

the

Display reading:

84

dB ± 0.1 dB

If the Display reading is out of tolerance

consult

the

LMS and Hold Circuit

2210

.5.

Increase

the

Input Signal to give a Display .reading

of

134,0dB

.

Decrease the

Input

Signal

30dB

in steps

of

10d8

and check

the

Linearity.

Tolerance: ±

0.4dB

.

If

the Linearity is out of tolerance consult

the

VCA and

Weighting

Network

2210

.4.

Adjust

the Input Signal (at 1 kHz) to give a Display reading of

134,0

dB.

Adjust

MANUAL

GAIN POTM. to 3,

16

Vat

"AC

Output"

Check the

four

Weighting

Curves according to

the

scheme

below

.

Use

134

,

0dB

and the AC Reading

as

reference.

In order to check the "

A"

Curve

below

20Hz

it

is necessary

to

measure

the

vottage on the

"AC"

Output

with

a Selective

Voltmeter

.

In

order to check the

"D

" Curve decrease the

Input

Signal by

10dB

.

In

the

scheme below

two

frequencies are given.

"Nominal"

and "Exact.

If

in doubt use the "Exact" frequency.

Frequency

"

C"

"B

"

"A"

Nominal

Excact

dB dB

dB

Hz

1 0

10,00

-14,3

-38,2

-70,4

20

19,95

-

6,2

-24,6

-50,5

100

10

0.0

-0,3

-5

.6

-19,1

Z50

251,2

0,0

-1.3

-

8,6

500

501

,2

0,0

-0

.3

-3

,2

lief

.

1000

0.0

0. 0

0,0

160

0

1585

0.0

0,

0

1.0

4000

3981

-0.8

-0.7

1,0

8000

7943

-3.0

-2.9

-1.1

20000

19950

-11.2

-11.1

-9

.3

"0

"

Tolerance

dB dB

-26,6

+1

-2

-20.6

!1

-7,2

!

0,3

-1

.6

:!:

0,1

-0.3

~

0,

3

0.0

_ ,

,_

4.9

_.,_

11,1

~

0,

3

5,5

+

0.

5

-0.7

-2.7

! 1

If

the

above readings are

not

obtainable

consult

the

VCA and

Weighting

Network

2210

.4.

Adjust

the Input signal (at 1 kHz)

to

give a Display reading of

100,0

dB

Adjust

MANUAL

GAIN POTM. to

FSD

at

the

meter

Decrease the

Input

Signal by

50

dB

Check the Decay Time of the LMS Detector:

50

dB in

11

. 5 s ± 2 s

Check

the

Decay Time:

-40

dB ref. 1

00

dB in 1 4 s ± 4 s

Adjust

the

input

voltage to give a Display reading of 1

00

,0 dB

Decrease the input voltage by

50

dB

Check

the

Decay Time:

50

dB in 1 7 s ± 4 s

tn

case of malfunction consult

the

LMS

and Hold

Circuit

2210

.5.

8.78

LMS

DETECTOR to

"Fast

"

LMS

DETECTOR

to

"

Peak"

INPUT LEVEL

to

"Low"

LMS

DETECTOR

to

"

Slow

"

1.

2.

Acoustical

Calibration

REF

.

1:

"In"

INPUT

LEVEL: "

High"

GAIN CONTROL MODE: "

Auto"

RLMS DETECTOR:

"Fast"

READOUT CONTROL: "

Clock"

EXT. FILTER:

"Out

"

WEIGHTING SELECTOR:

"Lin

."

REC

.PLAY BACK:

"Recording"

REF

. 1 to

"Out"

8.78

Checking Procedure 221 0. 1

Adjust

the

Input

voltage to give a Display reading

of

130,0dB

.

Check the Display Reading: 1

33,0

dB ±

0,

2 dB.

In case of

malfunction

consult

the

Preamplifier and Log Peak Detector

2210

.3.

Check

that

the

Readout Sequence can be selected

to

be 1 s

or

0,1 s by CLOCK.

Short

circuit

the

Input

to

ground

through

the

JJ

2614

Check

the

Internal Noise

WEIGHTING NETWORK

"

Lin"

"C"

"B"

"A"

"D

"

Display

reading

27

20

16

13

20

Adjust

MICROPHONE SENSITIVITY CORRECTION to give a Display reading

of

84

,0 dB + K

for

the

Microphone

used.

K = Ka - G

G is

normally

given on

the

back side

of

the

Microphone

Calibration

Chart

.

Use

the

Pistonphone Calibrator Type

4220

.

Check

that

the

Display reading indicates

the

exact Sound Pressure Level as indicated on

the

Calibration Chart

for

the

Pistonphone.

Remember to correct

the

Output

of

the

Pistonphone according to

the

actual

Barometric

Pres-

sure.

Tolerance ±

0,2

dB

.

Valid

from

serial no.

65

98

67

1-3

BROEL &

KJ~R

Nrerum - Denmark

Adjustment

8.78

J

10

JB

J.EB3-7v

j..

Ext

.

PS

J 9 Jll

n n n

lapprox

40kHz

. u u u

30Vpp

\

_rt

-13V

+13

V

(1

D

Power

Supply

c1i

C27

_!_

1

50V

T~

/

-85V G

e

P903

•

5V

TP1~

TP2~

-2.5V

For the

following

use an External

Power

Supply.

ZG

0124

Check the

power

consumption

:

430

rnA (battery voltage

3,5

V)

' (LIGHT: "

Max

.

")

Measure

the voltage on

the

anode

of

02

: -

13

V ± 1

00

mV

If necessary adjust P901 .

Measure

the voltage at

J5

2: 1

OV

± 3

mV

If necessary adjust

P904

.

Measure

the

voltage at

J5

pin 4:

-10

V ± 3

mV

If necessary

adjust

P903

.

Measure

the voltage at

J7

2:

200

V ± 1 V

If necessary adjust

P2

.

2210.2

Note.

The

measurement

of

the

Polarization voltage can

only

be done by means

of

a

Differen-

tial voltmeter.

Check

the

voltages on

R06

:

180

V ± 5 V

C13

:

50

V ± 2 V

TP1

:

5V±0,2V

TP2:

-2,5

V ±

0,5

V

C27:

-85

V ±

5V

Check the converter

frequency

approx.

40kHz

(

30

Vpp)

on

02

cathode.

Valid

from

serial no.

65

98

67

2-1

BROEL

&

KJ~R

Ncerum - Denmark

Preamplifier

and Log Peak Detector

2210.3

Technical Description

Input

Stage

(

zc

0007)

Input

Level

Pre

.

Amp.

ZE

0199

s---..~

·

·I

> I

·I

:#I

·I

> I

General

The signal

from

the

Microphone

is fed via the Preamplifier

ZG

0007

to

the

INPUT LEVEL Selector,

the

output

of

which

is fed to

the

Preamplifier

ZE

0199

.

Signol

Input

~--

1

I

~--------------

Logarithmic

Absolute

Detector

(LAD)

OPt.~

OtfsPtJ

The LAD consists

of

a

Buffer.

a Log. Det .. an

Amplifier

and a Rectifier.

The

AC

input

signal is fed to

the

collectors of

the

two

transistors at the

input

of

the

LAD. The base

of

these transistors are connected to

the

out-

put

of

a

Buffer

Amplifier

to reduce

the

input

current

for

the

transistors

.

Hold

Circuit

Reset

I

Input

from

LAD

rTn

I

_______

_

-v

The Hold

Circuit

works

as a

Max

. Hold Circuit. Together

with

the

LAD

it

forms

a Log. Peak Detector having a

short

rise

time

and a

slow

decay

time.

By activating GAIN CONTROL MODE

"Reset"

the

decay

time

of

the

Log. Peak Detector is accelerated

Log

.

Peak

Detector

Log

.

Absolute

Hold

Peak

r

f::~·,l

·1:;1

r 0

~"-'to

VCA

to

VCA

From

the

Preamplifier

the

signal is fed to

the

Voltage Controlled

Ampli-

fier

(VCA) and to

the

Log Peak Detector.

lAO

Output

AmplifiPr

I

-v

I

~o~s_j

The base-collector voltage is held to 0 V by

the

Amplifier.

The

Amplifier

feeds

the

emitters

of

the

transistors

so

that

the

collector

current

is

equal to the

input

signal

current

. Because

of

the

characteristics

of

the

transistors

the signal is

now

a

logarithmic

AC signal ·

The log. signal is rectified and fed to a Hold

Circuit

in order to

form

a

Log. Peak Detector

+V

Hold

Offset

ButtPr

Hold

Gain

~~..o---....._

_

___.

to

Meter

and

VCA

Gain

Limit

The Log. Peak Detector is

followed

by a

Buffer

Amplifier

.

Adjustment

of

the

off-set

and

the

gain is provided. A Gain

Limit

Circuit

is also provided.

This

circuit

will

ensure

a

constant

DC

Output

from

the

Buffer

Amplifier

when

the

Input

Signal is decreased by

60

dB or

more

.

The

Output

from

the

Buffer

Amplifier

is used

to

govern

the

gain

of

the

Voltage Controlled

Amplifier

in

the

Auto

mode.

8.78

Valid from serial no.

65

98

67

3-1

Preamp. and Log Peak Detector

2210

.3

Adjustment

3.1.

Reference

Generator

FILTER

SWITCH:

"Lin''

REF

. 1:

"In"

GAIN CONTROL MODE:

"Auto"

MANUAL

GAIN CONTROL:

"Min

."

INPUT LEVEL:

"Low"

Logaritmic

Absolute

Detector

REF

. 1

to

"Out"

Hold

Circuit

Linearity

of

Hold

Circuit

3-2

Measure

the Ref. signal at the red

wire

on

ZE

0199

:

251,2

Hz±

0,3

Hz

(3,981

ms

±

5t~s)

If necessary adjust

P502

Measure the voltage at

R502:

approx.

15,8

mV RMS

If

necessary adjust

P402

Before the

following

adjustments are made P601 should be turned all

the

way

CCW.

Input signal: 1

kHz

.

31

.6 mV

Measure the signal at

TPE

If necessary adjust P61 2 to the peaks

of

the signal are at the same level.

Input

signal:

1kHz

.

0.316

mV

Check that the peaks of the signal are at

the

same level.

If

necessary adjust P 611 .

The adjustment of P611 and

P612

should be repeated

until

the

difference between

the

peaks of the signal is

below

0.5

mV

Disconnect the

wire

(white) going to

J605

at

ZH

0128

and apply

the

input

signal to

J605

.

Set

the input signal to exactly

10mV

RMS, 251 ,

2Hz

.

Measure the voltage at

"Tape Recorder

Connector"

6:

-500

mV

de ± 2

mV

If necessary adjust

P602

.

Increase

the input voltage

40

dB and

meaure

the

voltage:

-2500

mV

de

± 2

mV

.

If necessary adjust

P605

The adjustment of

P602

and

P605

should be repeated

until

both levels are

within

the

to+er-

ance.

Decrease the input voltage

80

dB and measure

the

voltage:

50

mV

de±

5

mV

.

If necesaary adjust P601 .

Check the linearity according to

the

scheme

below

.

Input Voltage RMS

Output

mV at

Adjustment

to

J605

'

Tape

Recorder

Connector"

pin 6

3,16

v

(140

dB)

-3000

±

15

mV

1,

0V

(130

dB)

-2500

±

2mV

P605

316

mV

(120

dB)

-2000

±

5 mV

100

mV

(110

dB)

-1500

±

5 mV

31,6

mV

(100

dB)

-1000

± 5 mV

10mV

(

90

dB)

-

500

±

2mV

P602

3,16

mV

(

80

dB) 0

±

10

mV

Reconnect

white

wire

to

J605

.

8.78

8.

78

25ps

BVpp

251.2

Hz

~

BV

pp

251,2

Hz

/'"'\./'v

TPE

R-rF

2

~:V

@)-e34

@-433

P612

P611

Del

.

Del.

Off

se

t Boll.

Preamp.

and

Log Peak Detector

2210.3

OZ0014

E;j

p

502

Frf!!uency

Adjustment

white

~t

P605

Hold

Goin

ZE

0199

valid

from

serial

no .

65

98

67

blue

15

,8

mV

RM

S

(45

mVppJ

ZH

012

B

C!J

P602

P 601

Hold

Gain

Offset

Li

mi I

-500

mY

d

e(

P

602)

-2

500mV

dc(P605)

(also

ava

i

ab

le

al

"

Tape

Re

c

orde

r

C

onnector

" pin 6 l

3-3

IN

PUT

STAGE

,--------------

1

l

ni~

.

~~i;

n a

l

~===::J--~1-,.1

>

~

::~·

~

250Hz

1 o o

1

I

0

ZC

0007

1

--

-

-----

- 1-

--

I

~--

---

----

,

-----

1

I I I

I I

I

200V

I_

---

-

50V

L

OG

.

PEAK

D

ETE

CTO

R

r

----

P5

o- Fr

;;;-

;;;J

j.- -,

I I

I

Ref

_

I Gen.

I

1

_________

z~o~9

_

1

I

I I I

L

___

--

-

~

~E

_D~O_j

1

Lo

w

I

~

I

High

I

He

d.

I

NPUT

LEV

EL

REF

GENERA

TOR

PR

E.

AMP.

r -

----------

~

-----

-------

1

Red I I I 1

2

51

·

2

H

z/i

P

40

1 :15.

8mVRM

S I I 5

00mVRMS

,

--------

~

"'8

V pp I I

"-....

1

Pr

e.

Amp

. 1 I 1

I

Gr

een""'- I R 502 >

I----.--

J

_

5

.

03

8>1--I

-

-ii;;.;;-

--~~~

'7-

-~

o

301 J

306

1

coa

x I

1:

'<>-

--t-

o-t

---

::-::::-

'-=.---~

:_

______

~

oz

/

,

~3~

--

~

-

z~~

o_l!_:

52

I I

I I I

(ZE

01

99

) I

L

___

~

___

}o~

o

~

4

_

1

I I

I

lliDJ

§1J]

,-·

I

3,

16

V R

HS

Output

i\7

~

from

VCA

~

0

<.:>

u

·-

1

I

VC

A and

We

ig

ht

i

ng

I

Netwo

rk

22

10,4

·- ·-

to

ZH

01

28

[lfuJ

GAIN

CON

T

ROL

MOD

E

r-----

-----

--

----------

----

---

-

1 Logaritmic +

10V

VCA

Control

Volt

ag

e

"Auto"

1

A

bso

l

ut

e

Oet.

I

Del.

Bal.

TP

E

fr

om

ZE

0200

:

50

0 mV R

MS

*

Faclory

adjustment

I

1 J

605

I ±

10

v *

I

IR

32

I

lp512

Det.

Offset

> 15

ZE

0

16

6

7

I

+10

v

I J601/

16

2

------

--

----

------

.--

-

1

I

+10V

.i3

o11i6

- -,

I

J

301

/15 I

I

L-

--

~

-

~~

0

~1

I

o

Reset

Hol

d

Cir

cu

it

14

8

ZE

0

16

2

J

601/15

Reset

Ho

ld O

ff

set

p

602

Ho

ld

Ga

in

P6

05

J 6

01

/11

VC

A

Co

ntrol

Vol

tag

e

(A

ut

o

Mod

el

-

ZZOO

mV

LP

D

Output

ME

TER CI

RC

UiT

~

------

------------------

1

I I

I I FI

LTER

SWIT

CH

: L

in

. : O Batt. O

ff

I I BA

(\

I I

\sJ

I

' I C I

r--

---

-

---.-r--~

L

i

n

.

',

, I L in.l

''---

tt-

--

---

_

.J._

__

-

---

~

-

_ _ /

L----F

~~~~

I

b

lu

e/

white

-

10

V

Ex

t.

Rese

t

ZH

012

8 I

R

ec

ordpr

Co

nn

ecto

r

-·---

,

I

1 LPD '

1

O

ut

pul

l I

: I : ' L

HSond

Hol

d Cir

cu

it

,.

I J 1

210

I ZN

0176

I I

221

0,5

----

--

- - 1-

--

- - ·

-·-

~To

rd

Pl

ay

Ba

ck

I

0

1201

I I

'L

in_ I

I I

I

_____

----

--

-

I

Ma

in

Cha

ss

is I

------

~

-

~

·

-

·

-

1

Po

we

r

Supp

ly

I

Powe

r Su

pp

ly

1

-

2210

,2

-:-

4,5V

J

121

7

Ex

t

Po

we

r Con

necto

r

BROEL &

KJ~R

N<Brum-

Denmark

VCA and

Weighting

Network

2210.4

Preamp

.

Input

>

VCA

Log

.

Bias

Peak

and

I

Detector

rMan

.

Butter

MANUAlf

GAIN

~

CONTROL

GAIN

CONTROL

-lOY

HODE

•

The signal

from

the

Pramplifier

is fed to

the

Voltage Controlled

Amplifier

(VCA).

The gain of

the

VCA is governed by

the

setting

of

GAIN CONTROL

MODE.

In

"

Auto"

the

gain

is governed by a

DC

Signal

from

the

Log. Peak Detec-

tor

(LPD).

Weigh-

ling

Network

>

"Ext. Filter"

"AC

Output"

To

0

oo/

Weighting

Selector

TFrom

L

----.,

to

LMS

t---

.....

~~Circuit

to

LMS

Detector

AC

Out

Ampl.

By

controlling

the

gain

of

the

VCA

and

at

the

same

time

use

the

Gain

Control Signal to

inform

the

LMS

Detector

of

the

gain

setting

the

Dy-

namic

Range of

the

Sound

Level

Meter

is

expanded.

The

Gain

Regula-

tion

is

60dB

r--------------.....,

,-----------------.

I Limitl'r 1

to

Wl'ighting

from

Preamp

.

I

VCA

I

lOdBAmp/Buffpr

I

~Nl'twork

~

--~~--------r--;--~

I

>

L

_________

_

r-------,

I

;...

D

C.Var

. 1

I I

Bias

GPrwrator

Buffpr

from

LPD

IX'

MA

H

UA

L

::-GA:-:-1

N:-:--~~---~-.

CONTROL

-v

I

ZE0154

I

L

______

_j

DC

Var

Gain

Ratio

P7

The signal

from

the

LPD

or

the

MAN

. GAIN CONTROL

potentiometer

is

fed

to

the

Buffer

Amplifier

. The

output

of

the

Buffer

goes via a

Gain

Ra

-

tio

potentiometer

to

the

Bias

Generator-,

the

VCA and

the

Limiter

Circuit.

(ZE

0163

and

ZE

0165)

The Bias

Generator

is

providing

a DC

Voltage

to

the

input

of

the

VCA.

The

DC

Bias

will

ensure

that

the

input

transistor

will

conduct

for

both

the

positive and

the

negative

part

of

the

input

signal and

at

the

same

time

maintain

a max.

Gain

Regulation.

I

P6

DC

Tracking

I

J

to

LPD

in

"Hanuarmodl'

DC

Gain

toLHS

Dl'll'ctor

The Gain Control Voltage

for

the

VCA

is

supplied

from

the

Buffer

via

the

Gain

Ratio

potm

.

to

the

Output

Amplifier

of

ZE

0163

.

Via

the

DC

Tracking_ potm.

the

Gain

Control

Voltage

is fed to

the

Limiter

Circuit

on

ZE

0165

in

order

to

compensate

for

the

DC

Off

-set caused by

the

Bias Voltage applied to

the

input

of

the

VCA

.

The

Output

of

the

Limi-

ter

is fed

to

the

Weighting

Network

Circuits

on

the

ZE

0201

and

the

1 OdB

Buffer

Amplifier

.

The

Output

of

this

Buffer

is

fed

to

the

LPD

in

"Manual"

mode.

8.

78

Valid

from

serial no.

65

98

67

4-1

VCA and

Weighting

Network

2210.4

Adjustment

Output

adjustment

of

P

610

+

cw

ov

t

ccw

Manual

Gain

Min.

Control

Max

.

4.

1.

VCA

Off-Mt

FILTER SWITCH:

"Lin"

GAIN CONTROL MODE: '

'Man

."

'

MANUAL

GAIN CONTROL:

"Min

."

READ OUT CONTAOL: "Clock"

INPUT

LEVEL:

"

Hi~h

"

EXT.

FILTER

:

"Out"

REF

. 1:

"Out

"

AC

Amplif~atien

MANUAL

GAIN CONTROL to

"Auto"

INPUT LEVEL

to

"Low"

MANUAL

GAIN CONTROL to

"Man

."

MANUAL

GAIN CONTROL to "

Auto"

4-2

Output

adjustment

of

P

604

Min.

Manual

Gain

Control

ccw

cw

Max

.

Output

adjustment

of

P

606

Min.

~nual

Gain

Control

•

ccw

+

cw

Max

.

Before the following adjustments are made P601

(ZH

0128)

should be

turned

all

the

way

CCW.

Short circuit the Input to ground.

Connect an

Oscilloscope to pin

14

of

'Tape

Recorder

Connector"

and measure the voltage:

OV±50mV

If necessary adjust

P61

0.

Note.

The

instrument

should have been switched on

for

at least 3

min

. before

adjustment

of

P610

.

Move

MANUAL

GAIN CONTAOL

slowly

from

"Min

."

to

"Max

." and notice the

chal'lgint

of

the

DC

level. (VCA off-set).

P604

should be adjusted

so

that

the

changing

of

the

DC

level is proportional to

the

move-

ment of

MANUAL

GAIN CONTROL.

By

moving

MANUAL

GAIN CONTAOL from "

Min

."

to

"Max

." check

that

the

chang•ng in

the

DC

level is less than

30

mV.

If necessary adjust

P606

.

Check

that

the

DC

level

is

OV

DC±

30

mV at all positions

of

MANUAL

GAIN CONTROL.

If

necessary readjust

P61

0.

Since

the above adjustments influence each

other

the

adjustment

of

P604,

11~06

and

P'81

0

should be repeated

until

the

adjustments are

within

the

tolerances.

Before the adjustment of the amplification in

the

VCA is made,

the

adjustment

of

3.1 Ref.

Generator, Log. Absolute Def., Hold

Circuit

should be checked.

Input signal:

31,6V

RMS,

1kHz

Check the voltage at

'To

Ext. Filter

":

1 V RMS

Tolerance: ± 5 mV

If necessary adjust

P609

Decrease

the

input signal by

40

dB

Check the voltage at '

To

Ext. Filter": 1 V RMS

Tolerance: ± 5 mV

If necessary adjust

P607

Increase the input signal by

20

dB

Check

that

clipping

will

occur symmetrical on Signal

Output

I ("Tape Rec::.Connector"

pm

14)

when

moving MANUAL GAIN CONTROL from

"Min

. to

Max

."

Input Signal:

31,6

mV

Check

the

voltage at

'Tape

Recorder

Connector"

1: 1

000

mV

± 2

mV

If necessary adjust

P603

Decrease the input signel

40d8

Check the voltage at

'Tape

lllecorder

Connector"

1:

-1000

mV

± 2

mV

If necessary adjust

P608

8.78

MANUAL

GAIN CONTROL to "

Man

."

DC

Linearity

4.2.

Weighting

Networks

INPUT LEVEL:

"Low"

GAIN CONTROL

MODE

:

"Man."

LMS

DETECTOR:

"Fast"

FILTER SWITCH:

"Lin"

READ OUT CONTROL:

"Clock"

EXT. FILTER:

"Out"

Nominal

frequency*

in

Hz

10

20

40

100

200

400

1000

2000

4000

10000

20000

I

Adjust-

ment

at

1000Hz

8.

78

Exact

frequency

in

Hz

10

,

00

19,95

39

,

81

100,00

199.5

398.1

1000

1995

3981

10000

19950

VCA

and

Weighting

Network

2210.4

Set

the

voltage at

Input

voltage

"'Tape Recorder

Connector

"

Voltage

at

Tolerance

1,

by

means

of

"To Ext.

Filter"

Volt

0 dB = 1

00

mV RMS

MANUAL

GAIN CONTROL

Volt

OdB

1500

mV

1

±0,2

-10dB

1000

mV

1

±0,

1

-20dB

500

mV

1

±

0,2

-30dB

OmV

1

±0,2

-40

dB

-

500

mV

1

±0,2

-50

dB

-1000

mV

1

±0,

1

-60dB

-1500

mV

1

±

0,2

Check

the

linearity

of

the voltage

at

''To Ext. Filter··

The

adjustment

of

P603

and

P608

should be repeated

until

the

voltage is

within

the

toler-

ance.

Apply an

input

signal

90

dB

below

FSD

and

adjust

P601

for

a voltage

at

"Tape

Recorder Con-

nector"

6:

50

mV

± 5

mV

When

the

VCA and the

LPD

circuits

have been

adjusted

it

is necessary

to

adjust

REF. 1 and

REF

. 2. Consult

2210.1-1

Apply

the

input

signal

through

JJ

2614

Input

Signal:

31

60

mV, 1 kHz.

Set

MANUAL

GAIN CONTROL to 0 dB

amplification

at

1000Hz

Check

the

Weighting

Networks

according to

the

scheme

below

by

measuring

the

voltage

on

"AC

Output

"

using

a Selective

Voltmeter

A B

c

D

Tolerance

Weighting

dB

-70.4

-38,2

-14,3

-26,6

+

1,0

,

-2,0

-50

,5

-24,2

- 6,2

-20,6

+

1,0,

-2,0

-34,6

-

14,2

-

2,0

-14,7

+ 1

,0.

-2,0

-19

,1 -

5,6

-

0,3

-

7,2

+

0,1,

- 0,1

-10,9

~

2.0 0 -

2,6

+

0,3,

-0,3

-

4,8

-

0,5

0 -

0,4

+

1,0,

- 0

0 0

0

0,0

+

o.o

.

-0,0

+

1,2 - 0,1 -

0,2

+

7,9

+

1,0

,

-0

+

1.0

-

0.7

-

0.9 +

11,1

+

0,3.

-

0,3

-

2,5

-

4,3 -

4,4

+

3.4

+

0,7,

- 0,7

-

9,3

-11.1

-

11,2

-

2,7

+0,1.

-0,1

P702 P703

P704

P701

Valid

from

serial

no

.

65

98

67

4-3

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Brüel & Kjær 2210 Service Instruction

Brüel & Kjær 2210 Service Instruction

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