Tandberg TD-20-ASE Service manual

TANDBERG'

TD

20

A-SE

Circuit Diagrams

and

Alignment Instructions

Electrical Make

adjustments TD

the adjustments in

are listed here. Many

adjustments have already been

correctly made.

of

20A-SE

order

the

adjustments

the

in which they

require

Bias Adjustment Before

ment

adjustment, make

potentiometers

mid-position.

(front

panel)

on the front

sure that the Bias Adjust-

panel

are

in

the

A\

Clean

and degauss adjustments. lt is already been Service

Maxell for

recording.

Necessary

- d.c.

voltmeter.

- 2 high

correctly

Manual

UD

for

XL

or equivalent

equipment

impedance voltmeters

universal meters).

Frequency

-

- Audio

Distortion

-

Wow

-

Test No.

counter.

generator.

meter.

meter

(required

tapes:

2 -

Azimuth adjustment

15,000 No. 3 No.

Playback

-

Playback

4

7% ips.

No.

-

11

Speed check,

the

tape

assumed

that

adjusted

the TD

for

Hz,7/z

cule,

level

1000

path

before and after

the

tape

as

described in the

part

20A,

tapes

wow

No. 714127.

should be

(do

NOT use

test only).

playback

ips.

DIN

19H,7%ips.

adjustment,

Hz,

7%ips.

path

head,

4OO

has

used

Hz,

Checking the Connect a

frequency

oscillator

frequency

counter directly

head. Adjust

recording with check are within C303, DUMMY Then

frequency

the

mono,

in

!.2

kHz. lf

check the

to 123.5

C313 on

left

and

outside the tolerance, adjust

LOAD ADJ.

frequency

and right.

Checking Connect

recording

the

Bias Adjustment

an audio-generator

at7%ips

speed of a22kHz below normal recording Monitor level OUT when

switch to

measured with

within

are

turning

Adjustment To

voltmeter

performed

be

on

Tape.

a.c.

approximately

the Bias

EOT/BOT

of

Adjustment

without tape. Measure

3, contact

board. Adjust

R422

(on

the

logic

on the voltmeter.

record

kHz in

to the

stereo the logic board. Then right,

in

the frequency

that

on the audio

board.

stereo and mono

(front

panel)

to LINE 1. Start stereo

30 dB

(0

level

Check

that

voltmeters

+

signal

dB). Set

the

on

the

3 dB to

the

output

LINE

-

5

potentiometers.

sensor

with a d.c.

412 on

the logic

board) to 1.2 V reading

left

,^

dB

Test

Adjustment

No.

or check Azimuth,

1.1 playback

1.2 Playback curye DIN 19H

1.3 Playback tNet

1.4

Speed 11

No.

Test tape

'

tape

Test

Set the

No. deck

Playback.

2

c^,,-r:-^.:^-.

head

'l

1

is supplied on a small reel.

LquoI4oLrvrr.

Normal.

Playback.

3

Equal Nomal.

Playback.

4

Equalization: Normal Somial

Playback. Frequency

Measuring

to

tnstrument Measure at

voltmeters

a.c.

ization:

voltmeters

a.c. voltmeters

or

counter

This

Correcl

Adjust

LINE OUT Azimuth

LINE OUT

test tape should be spliced into a tape on a larger reel

screw, playback

head Playback

E.Q. R501

Playback level

R

I 69/R269

readino Maximum

output, see comments

+2dB at 18 kHz

adj.

/R601

0.9 volt 7'h

! 995-1005 in 7% ios.

o.5'/.

Hz

Speed

Comments

7% ios Maximum output

7% ips. Playback

ips.

curue, DIN

following

the

kHz,

18

15 kHz, 10 kHz, 4 kHz,

'1000

(ref.).

Hz

18 kHz.

at

taoe No.

Test

Hz

in 7% ips.

1000

frequencies: 1000

1 1 * is recorded at

or best compromtse.

'19H,

The tape

R501/R601

Ad.iust

contains (reference)

Hz

Hz, 40 Hz

125

to + 2

4

dB

^al

Tes

Adiustmenl

No.

or check

2.1

Bias

pre-adjustmen

11

Azimuth, rsord head

2.5

Record/ playback curues

Record/ playback curyes

Record/ playback

curyes

Record/

2.6

playback curues

Source,/ Tape

Program

2.6

meter adjustment

DYNEO@

2.9

level adjustment

2.1C Distortion

Wow

2.11

flutter

and

Measuring instrument

voltmeters

a.c.

voltmeters

voltmetem

voltmeters

a,c. voltmete6

a.c. voltmeters

voltmeters

Program meters

voltmeter/

distortion merer

Wow

and flutter meter

Measure at LINE

LINE

LINE OUT Becord.

LINE OUT Record.

LINE OUT

LINE OUT Speed: 7%

LINE OUT

LINE OUT Record.

LINE OUT

Set the deck to

OUT Record.

Speed: 7% Equalization: Normal.

OUT Record.

OUT B ecord.

77:

Speed: Equalization: Normal.

Speed: 7% ips Equalization: Normal.

Speed: 15 ips. Equalization: Normal,

Speed: 15 Equalization: Special.

Speed: 7% Equal ization: Speria l.

Record. Speed: 7% ips Equalization: Normal.

Equalization: Normal.

7%

Speed:

Equal ization:

Normal.

7% ips

Speed;

Equalization: Normal

Record. Tape Connet

Monitor switch io

Tape

ipl

Tape

ip:

Tape

fape

ips.

Tape Use

ips

Source/ Tape

ips

Source

ips

Source Connect an audio

Tape

Procedure Connet

normal

Then

turn R151 and

Connst

10O0

Hz reference head

to maximum

Connst signal

30 dB below normal recording

(0

level from

the reference

0 dB.

Check that the 20 Hz

Use the Check Adjust if necessary R251. lf Equalization: Adiust if necessary with R139/R239.

Use

the same reference level. Turn Chek

the same level. Check that the output level do not deviat€ more than i 2 dB

Hz

20

Connect an audio-generator 1000 to 0.6 V on the Monitor higher on the

Connect Adiust with the meters to 0 dB with

input levels

the

set of the

Connmt Record to Distortion

lowest

Wow and Weishted Peak

value DIN 45500

an

audio-generator

r*ordjng

an audio-genemtor

signal

30

level.

Then

an audio-generator

Then

dB).

to 25,000 Hz.

recording level

same

that

output

the

re-adjustment is

Normal do not dwiate more than r 2 dB from

recording level

that

the outDut

rffording level

Hz.

to 25.000

voltmeters to Tape. Then

switch

voltmeters.

an audio-generator

Input Levels to 1.5 V reading on the

to - 3

program

meters to + 2 dB with

chassis).

an audio-generator at 1000

V reading on the voltmeters and

0.9 maximum 0.5%.

the wow and

speed:

ilutter

maximum:

RMS

to

LINE

(0

level

dB). Adjust RlSl

R251 counter

LINE t.

to

dB below

normal recording

rmord

a 25,000 Hz

reading or best

turn the

level. Turn

output level do not

level do not

with

the

level

R158 and R258

generator

dB on the

flutter meter to

P.4.

compromise on

to LINE 1. Start

generator

the

as in test

PLAYBACK

deviate

done, check once again that

test

as in

generator

to

not

do

dwiate

in

as

test 2-3.

Hz

on the LINE OUT.

adjust

1000 Hz to LINE 1. Set

LINE 1. Set the

to

program

3% OJO%

O.14y' 0.08%

1.

Set the

clockwise to

Start rcording

signal and

(0

level

to 12.5

deviate more

Use

2.3. more

E.O. ADJ.

Use the voltmeters readings as

2.3. kHz and adjust R135/8235 to 0 dB.

30

more

Use the voltmeters readings as

to LINE 1. R142

(Output

meters.

oYNEQ

the

Hz

the distortion meter

or

LINE 1.

ips. 7%ips.

generator

and R251

level

rmording

dB). Use

kHz and

to

the

Set

and

Left and

Then

0.05%

to 1Z.b maximum

to

from

2 dB

-

the

kHz

25

voltmeters

than

B5O1/8601

than

Adjust in

the

F.242

generator

SENSITIVITY

read the distortion on the

Read

maximum readino.

at 7%

ips. of a

(O

dB). Use the

the

turn

azimuth

voltmeters.

1000 Hz

of a

the voltmeters

R151

adiust

and adjust

J

than

2

readings as reference level.

1

from

3 dB

and,/or

the output

20

i

2

from 20 Hz to 30.000

dB

Source with

deck to stereo

that

the

so

the Monitor switch to Source.

voltmeters. Then

Right

on maximum).

kHz. Adjust with

to 1

generator

set the

LINE OUT in

on the

15 ips.

0.m%

0.06%

kHz

30 dB below

outour level.

voltmeter

readings

screw on the record

readings

and B25l

R139

from

dB

20

lwel in 7% ips,

Hz

to 25,000

from

level reading is 1 dB

ADJ.

generator

as

to 0.5 dB

R23g

and

Hz

to 30.000 Hz.

BIAS

ADi.

Hz.

refereance

the Input Levels

recording 3nd set the

adjust the

to 1 8 kHz

(on

leit side

to LINE

LINE

highest and

reference

to

R151/

Hz.

program

the and

1.

OUT

as

FREO. ADJ.

OSC.

PLAYBACK EO.

PLAYB. R169 L LEVEL

Location

IS

THE LOGIC 8OARO.

ON

ADJ. IS ON

THE PLAYBACK

;

B

.METERADJ

I

qrqn

--

R269

R a

R258

METER AOJ,

of Adjustment

AMP.

BOARD.

points

REC. LEVEL L

Ra a

R242

the

on

Audio

Rt42

REC. EQ. ADJ.

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