TANDBERG 3400X User manual

IffiEffi
SERVICE
MANUAL
SoooxD

CONTENTS
l.
l.l
r.2
,
2.1
99
3.
3.1
3.2
3.3
3.4
c.c
3.6
4.
4.1
4.2
4.3
4.4
4.5
5.
5.1
5.2
5.3
5.4
c.5
6.
6.1
6.2
6.3
6.4
6.5
7.
7.1
19
7.3
8.
8.1
8.2
8.3
8.4
9.
9.1
9.2
10.
11.
11.1
rt.2
11.3
Page
Introduction.... ..,....3
General ....3
Removingthetoppanel . ......3
Maintenance.... ...,.,.4
Cleaningthetapepath.. .......4
Lubrication .......4
Mechanicalchecksandadjustments.. .......5
Checking
the take-upforce andwinding force. . . . . . 5
Adjustingthetake-upforce. ....5
Adjustingthewindingforce. ...6
Adjustingthebrakes .....8
Rubberdrivebelt .......8
Pressurepadarm ...9
Tapepath ...10
Capstan .....10
Headparallelism. .......10
Tapeguideposts
and
guide
screws.
.. .. .. . . .11
Pinchroller .......11
Flutterroller. .....12
Head
alignment
with Tandberg test tapes,
four tracks . . . . .13
Playbackhead. ....13
Recordhead. .....13
Height
adjustmentby
trackmeasurement... ......13
Biashead ....I4
Erasehead ...I4
Headalignment
without Tandbergtest tapes,
four tracks . . . . . . .15
Playbackhead. ....15
Recordhead. .....15
Biashead ....15
Erasehead. .......15
Aligning the hum shieldfor the playback head. . . . .15
Headalignment,two
tracks .....16
Playbackhead. ...16
Recordhead. .....16
Erasehead ........17
Circuits .....77
Oscillator. . . .I7
Photoend-stop ........I7
Recordandplaybackfrequencyresponses . . .18
Faultinthetotalresponse
curve,onechannel..... ......19
Modifications... .......20
Changingthelinevoltageand
frequency... .......20
Changingfrom four tracksto two tracksversion . . . .20
Blockdiagrams ....20
Electricaladjustments.... .....22
Outputamplifiers
(3400X) .....22
Dolby*leveladjustments
(3600XD). .......22
Adjustments,allmodels.... ...23
Circuitdiagrams .... from page24
* Theword Dolby isa Trade
Mark of Dolby LaboratoriesInc., USA
-----.....-
-
t
a

1. INTRODUCTION
-
1.1 GENERAL
Only LH (Low Noise/HighOutput) tape shouldbe
used
for recording.Makesurethat the headsand
tapepath areclean.
To check
theheads:
-
l. Remove
the front head
coverby depressing
the
springloaded
buttonsatboth endsand
lifting
the coverstraightupwards.
2. Remove
thebackcover
by depressing
the spring
on its rearsideandlifting straightupwards.
When
electrical
adjustmentsareto be made,the
bottom panelmust
beremoved.
Thetapepathmust
bedegaussed
both beforeand
after adjustment.
Do not switch off the degausser
until it isabout 3 feet from the tapepath.
To makemagnetizedpartsof the tapevisible,
dip
the tapein "MagnaSee".Thisis a mixture of iron
oxide powder andalcohol.Iron oxide powder can
beobtainedfrom our service
department.
A
NOTE! All paragraphs
in this manualare
valid for:
Model3400X,from serialNo. 4300000
Model3500X,alldecks
Model3600XD,from serialNo. 4200000
1.2 REMOVINGTHE
TOP
PANEL
Remove
the headcoversandthe speedselector
knob. Then remove
the screws as
shownin Figure
1.1.
Removalof thetop panel will usually
only be
necessary
for checkingand adjustmentof clutches
andother partsin the drivemechanism.
Fi4.1.1. Toppanelscreu)s
.HHs..[n
-

2. MAINTENANCE
Fig.
2.1 Cleaning
the taPe
Path
2.1 CLEANING
THETAPE
PATH
It isimportant that the tapepath is cleanbefore
adjustments
aremade.If the heads
andguideposts
have
beenadjusted,
the tapepath must be de-
magnetized.
Cleaning
shouldbe carried
out with cotton-bud
sticks
(Q-tips)moistenedwith purealcohol
or
methylatedspirit. A special cleaning
kit called
"Tandberg ProfessionalTapeHeadCleaner"is
alsoavailable.
Aerosol
sprays
indentedfor videotaperecorders
maybeused,
but it isnot sufficient
just to spray
theparts;cotton-budsticks
mustalso
beused.
Obstinate
depositson guide
posts
shouldbe first
well softened
with the cleaning
agent
andthen
removed
with the aidof a toothpick.
ThepinchrollerA should
becleaned
if the tape
runsunevenlyor if thereare
visibledeposits
on
theroller (4 to 6 times
ayearshould
besufficient,
even
if the tape recorder
ismuch used).
Makesure
that the pinch roller is dry after cleaning.
2.2 LUBRICATION
NOTEIDo not usc
morethanone
dropof oilon
eachbearing,
asexcessive
oilmaypenetrate
into
thedrive
mechanism
and
disturb
friction
conditions.
The turntables,flywheel andtransferwheelare
mounted in selflubricating bearings
andshouldnot
need
attention under normal conditions. If for
some
reasonlubrication appearsto be necessary,
use
Teresso
oil No 43 or 47 from Esso.
The motor shouldbelubricated after every
3000hoursof operation.
Apply only one dropof
Teresso
oil No. 43 or 47 from Esso.
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A3.
3.2
3.1
MECHANICAL
CHECKS
AND
ADJUSTMENTS
CHECKING
THE
TAKE-UP
FORCE
AND
WINDING
FORCE
Fig. 3.1 Checking
the windingforce.
A 7" reel
with ahole
drilledin it 80 mm from the
hub holeisrequiredtogetherwith atorque gauge.
Insertthe legof the torque gauge
into the drilled
hole.The reelshouldbe allowedto rotate slowly
in the direction of the clutch torque while the
measurements
areperformed to obtain the speci-
fied
values.
see
table3.2.
ADJUSTING
THE
TAKE-UP
FORCE
Fig. 3.3 Adjusting the take-up
force.
NOTE! Do not touche the textile sideof the
belt with your fingers.
The rubber drivebelt doesnot moveduring normal
forward drive.This isbecause
atextile belt pro-
vides
the take-upforce viaadrivewheelmounted
behind the take-upturntable.
Adjust the take-upforce by movingthe spring,see
Figure
3.3.
If thewindingforce
isnot correct
it should
be
adjusted
as
explained
on thenext page.
]
Turntable Operating
lever
position Playback or
wind force
Rieht 25- 30
e*
Right >> 9o-2so
g*
Left 90-250
p*
Table
3.2 Clutch
torque
x It is
normal
for thewindingforce
to increase
20-30%
after
themachine
has
been
in conrinuous
operation
for sometime.
O

3.3 ADJUSTING
THE
WINDINGFORCE
f-x
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..d5"
tl
U,
Adjusting the reelturntables.
Thewindingforceisdetermined
by the springs
A.
See
Figures3.5and3.7.If the tensionandthe
springsdo not change,the winding force is deter-
mined by the play on the reel turntable and the
clutchleaver.If thetension isstillnot correctafter
adjusting
the play, replace the spring
A.
Withthe
joystick in the FREEposition,
theplay
ontheturntableshould
bebetween0.5and1mm
as
shownin Figure3.4.Theplay on the left turn-
table
canbeadjusted
by turningthenut on the
turntable spindle.The play on the right turntable
canbeadjusted
by turningthe turntablepulley.
NOTE! If theturntablepulley (rightturntable)
must
beunscrewed from theturntable
it shouldbe
glued
into positionaftertheplayhas
beenadjusted.
Fig,
3.4 Checking
the
play on theturntables
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Thesupply turntable
fil
Fig. 3.5

-
Fig.
3.6 Checkingthe
play on theclutchleaers
Adjustingthe clutch lever.
With
the
joystickin the NEUTRAL (middle)
position,
theplayon the clutch
levers,rightand
left,shouldbebetween
0.5and1mm.
To adjust
this
play,
turn the screws
B shown in
Figure
3.6.
When
the play on the turntable andthe clutch
levers
has
beenadjusted,
the winding forces
will
be
correct.Check
these
forces
with theaidof the
table
onpage 5.Adjusting
thebrakes- see next
page.
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Fig.
3.7 Thetake-up
turntable

3.4 ADJUSTINGTHE
BRAKES
This adjustment procedure
turntables, but referende is
table.See Figure3.8.
isthe samefor both
made to the right turn-
Set
thejoystick to the ) position. Check that the
clearance
between the brake pad and the turntable
is I mm (0.4") approx. If necessary adjust screw D.
Set the joystick to ( , alternatively D and
check the clearance.
3.5 RUBBERDRIVE
BELT
The rubber drive belt doesnot move in PLAY
mode. This is becausea textile belt provides
the take-up force via a drive rvheelmounted
behind the take-up turntable.
When changingthe drive belt, make surethat the
new belt sitscorrectly on the motor pulley as
shown in Figure3.9. The belt must sit in the top
two belt grooves
and not in the samegroove.
Thebelt must not crosson the wrons side
of the
pulley.
Fig.3.8. ,ldjustirtg the brakeson the right tunttable
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Fig.3.9 Replacingthe driuebelt
T

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a
Thelifting arms
for the drivebelt shouldbe
adjusted
whenthe
joystick isin NEUTRAL (nrid-
position).
Adjust for I mm clearancewith flat
pliers
asshownin Figure 3.10.Adjust A first and
theB.
3.6 PRESSURE PADARM
Withthe
joystick in the ) position,
the tension
from thepressure
padarmagainstthebracket
should
be
between80 and100 g.Thispressure
should
bemeasured
as
shown
in Figure
3.11.
Adjustby bendingspringA which presses
the
pressure
padarm
againstthehead. Checkthat the
pressure
pad
arm
isparallel whenit meets
the
bracket.
Fi9.3.10.
Adjustingtheclearanceon the driuebelt
Fig.3.
1
1.lvleasuring
the
pressure-pressure

4. TAPE
PATH
4.1 CAPSTAN
Before the heads
and tape guide posts are adjusted,
the position of the capstanmust be checked.
Useipecial tool No. 5 asshown in Figure 4.1. All
three legsof the special
tool should rest on the
upper mounting plate. If one or more of the legs
dois not rest on the plate' the capstanneeds
adjusting.To adjust the capstan,
loosen the three
coioured screws and adjust the capstan until all
three legsof the tool rest on the plate. Tighten up
the screws and check again that the legsare all
touching the Plate.
NOTE! The capstan
will not go out of adjustment
with normal use and transit.
4.2 HEAD
PARALLELISM
Check that the heads are parallel with the aid of a
tape path gauge'
seeFigure 4'2. This adjustment
aflects the passage
of the tape through the tape
path, and where the headsareseriously out of
ilignment the complete tape path must be checked,
see
next page.
Fig.4.1.
Actjusting
thecapstan
with special
tool No'5'
4N
1
s
Adjust
Forwards Adjust
Backwards
r-TIl
L__J
Correct
Zenith
Fig.4.2.
Adjustirtg
with thetape
pathgauge'
(s'