MBB HELICOPTERS

MAINTENANCE MANUAL MBB .B0 105

803 WINDSHIELD WIPER SYSTEM

Table of Contents

Paragraph T i tle Page

803 .1 DESCRIPTION .WINDSHIELD WIPER SYSTEM ........... 3

803 .2 TROUBLESHOOTING .WINDSHIELD WIPER SYSTEM . . . . . . . . . . 4

INSPECTION SCHEDULE .WINDSHIELD WIPER SYSTEM . . . . . . . . 7

INSPECTION FOR CONDITION .WINDSHIELD WIPER SYSTEM . . . . . 8

FUNCTIONAL TEST .WINDSHIELD WIPER SYSTEM . . . . . . . . . . 8

Removal-motor . . . . . . . . . . . . . . . . . . . . . . . 9

I n s t a l l a t i o n .motor . . . . . . . . . . . . . . . . . . . . 10

Removal-converter .................... 10

I n s t a l l a t i o n .c o n v e r t e r ................. 11

Replacement .w i p e r b l a d e ................. 12

Replacement .f l e x i b l e d r i v e s h a f t . . . . . . . . . . . . . 12

Adjustment .p r e s s u r e of b l a d e on windshield ....... 12

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803 - 1 DESCRIPTION - WINDSHIELD WIPER SYSTEM

1. General

The purpose of t h e windshield wiper system i s t o m a i n t a i n good forward

v i s i b i l i t y f o r t h e p i l o t d u r i n g inclement weather.
The system i s o p e r a t e d by t h e 2ME WIPER t o g g l e s w i t c h which can be
p o s i t i o n e d t o ON, OFF, and PARK. There a r e two c o n f i g u r a t i o n s which
d i f f e r i n t h e way t h e y a r e grounded. I n c o n f i g u r a t i o n I, t h e motor 4ME i s
grounded d i r e c t l y t o t h e f u s e l a g e , while c o n f i g u r a t i o n I1 has t h e motor
connected t o ground v i a dropping r e s i s t o r 3ME. Operation of both c i r c u i t s
is identical.
C o n f i g u r a t i o n I: S/N 6 t h r u 160 ( f i g . 803-1)
C o n f i g u r a t i o n 11: S/N 161 and subsq. ( f i g . 803-2).

2. Description
The windshield wiper comprises a motor which i s screwed t o t h e underside
of t h e f r o n t f l o o r p l a t e i n t h e c o c k p i t , and a c o n v e r t e r which i s
a t t a c h e d w i t h a b r a c k e t t o t h e c e n t e r p o s t of t h e windshield. A f l e x i b l e
d r i v e s h a f t c o n n e c t s t h e motor t o t h e c o n v e r t e r .
Power from t h e PP22 a u x i l i a r y bus i s s u p p l i e d t o t h e 4ME motor through
t h e 1ME c i r c u i t b r e a k e r , 2ME wiper switch, and t h e 3ME dropping r e s i s t o r .
An automatic reset t h e r m a l p r o t e c t o r b r e a k s t h e motor c i r c u i t when t h e
temperature of t h e motor c a s i n g exceeds 90 ' C , and makes t h e c i r c u i t
a g a i n a u t o m a t i c a l l y when t h e c a s i n g has c o o l e d s u f f i c i e n t l y .
3. Operation
The wiper system i s o p e r a t i o n a l when t h e wiper c i r c u i t b r e a k e r i s
d e p r e s s e d and power i s s u p p l i e d t o t h e PP22 a u x i l i a r y bus. When t h e WIPER
t o g g l e s w i t c h i s set t o I ( O N ) , power i s s u p p l i e d t o t h e motor which
d r i v e s t h e c o n v e r t e r through t h e f l e x i b l e d r i v e s h a f t , c a u s i n g t h e wiper
arm t o sweep back and f o r t h a c r o s s t h e windshield with a s t r o k e a n g l e of
90". When t h e wiper moves i n t o t h e stow (PARK) p o s i t i o n , a l i m i t s w i t c h
i n t h e motor i s a c t u a t e d c a u s i n g t h e c i r c u i t t o s h o r t and t h e motor t o
s h u t down. Because t h e wiper switch i s spring-loaded i n P ( P a r k ) , it
r e t u r n s a u t o m a t i c a l l y t o 0 (Off) when r e l e a s e d . The 3ME dropping r e s i s t o r
l i m i t s c u r r e n t consumption when t h e 2ME wiper s w i t c h i s i n t h e p o s i t i o n P
(Park) .

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803 - 2 TROUBLESHOOTING - WINDSHIELD WIPER SYSTEM

General

- Use t h e f o l l o w i n g w i r i n g diagrams i n t h e Wiring Diagram Manual (WDM) f o r

t r o u b l e s h o o t i n g t h e System:
C o n f i g u r a t i o n I: 803-1
C o n f i g u r a t i o n 11: 803-2
- I n s p e c t a l l a s s o c i a t e d e l e c t r i c a l connections f o r s e c u r i t y .
- Check a l l a s s o c i a t e d s w i t c h e s and c i r c u i t b r e a k e r s f o r unimpaired
mechanical f u n c t i o n i n g .

- Engage e x t e r n a l power supply.

( 1 6 P b a t t e r y s w i t c h on instrurnent p a n e l i n BAT OFF I EPU ON p o s i t i o n ) .
- Depress 1ME c i r c u i t b r e a k e r on instrument p a n e l .

No. TROUBLE SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION

Motor 4ME f a i l s t o 4ME motor Check 4MEa connector

s t a r t when s u p p l i e d def e c t i v e f o r v o l t a g e ; check
w i t h power (wiper e l e c t r i c a l connections f o r
s w i t c h i n ON p o s i t i o n ) good c o n t a c t :
Check v o l t a g e a c r o s s
motor u s i n g w i r i n g
diagram f o r t h e
appropriate configuration.
Replace motor i f d e f e c t i v e ;
r e f e r t o p a r a s 803-6
and 803-7
Bonding jumper Check bonding jumper
c o n n e c t i n g 4ME f o r continuity;
motor t o f u s e l a g e e s t a b l i s h c o n t a c t and
l o o s e and without t i g h t e n screwlbolt
contact connection

Activated o r I n s p e c t motor c a s i n g
d e f e c t i v e thermal f o r excessive overheating.
p r o t e c t o r i n 4ME I £ motor does n o t
motor automatically r e s t a r t
a f t e r c o o l i n g down,
r e p l a c e motor i n
accordance w i t h
p a r a s 803-6 and
803-7

Table 803-1 Troubleshooting (1 of 3)

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TROUBLESHOOTING ( c o n t inued)

No. TROUBLE SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION

Def e c t i v e 1ME Check c o n t i n u i t y of

c i r c u i t breaker o r c i r c u i t b r e a k e r and
2ME wiper s w i t c h wiper switch; check
connections f o r good
contact .
Replace d e f e c t i v e
switchlcircuit breaker

De f e c t i v e Check w i r i n g f o r
electrical continuity using applicable
wiring w i r i n g diagram.
Replace f a u l t y w i r i n g .

D e f e c t i v e 3ME Measure r e s i s t a n c e .
resistor Replace d e f e c t i v e
resistor

Configuration I1 Check f o r c o n t i n u i t y of
only : bonding jumper.
Bonding jumper Establish contact
on 2ME wiper s w i t c h and t i g h t e n s c r e w l b o l t
i s l o o s e and connection
without c o n t a c t

2 Motor r u n s b u t Defective converter Replace c o n v e r t e r i n

wiper arm does accordance with p a r a s
n o t move 803-8 and 803-9

Defective f l e x i b l e Replace f l e x i b l e d r i v e
drive shaft s h a f t i n accordance
w i t h Para 803-11

3 Wiper arm o s c i l l a t e s Excessive c u r r e n t Replace motor i n

t o o slowly consumption when accordance with p a r a s
motor o p e r a t e s 803-6 and 803-7
under f u l l load;
brushes probably
worn

4 Wiper f a i l s t o s t o p Cam a s s e m b l y / l i m i t Replace motor i n

i n stow p o s i t i o n s w i t c h i n motor accordance with p a r a s
even w i t h t o g g l e defective 803-6 and 803-7
switch i n PARK

Table 803-1 Troubleshooting ( 2 of 3)

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TROUBLESHOOTING (continued)
--

No. TROUBLE SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION

5 Wiper does not r e t u r n Defective 2ME Check c o n t i n u i t y of

t o stow p o s i t i o n wiper switch wiper switch; r e p l a c e
although wiper d e f e c t i v e wiper switch
switch i s set t o
PARK

Configuration I Check c o n t i n u i t y of
only : bonding jurnper ;
Bonding jumper establish control
on 2ME wiper switch and t i g h t e n s c r e w l b o l t
i s l o o s e and connections
without c o n t a c t .
Def e c t i v e Check c o n t i n u i t y of
electrical wiring using applicable
wiring w i r i n g diagram;
r e p l a c e f a u l t y wiring
Defective thermal Replace motor i n
protector accordance with p a r a s
803-6 and 803-7
6 Wiper b l a d e s do not Damaged o r Replace wiper blades
provide a c l e a r d e t e r i o r a t e d wiper i n accordance with
windshield blades p a r a 803-10
Tension on wiper Adjust p r e s s u r e of
b l a d e s t o o low b l a d e on windshield
i n accordance with
p a r a 803-12

Table 803-1 Troubleshooting ( 3 of 3)

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803 -3 INSPECTION SCHEDULE (refer to Chapter 101) I

Revision 18 CHAPTER 803

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803 - 4 INSPECTION FOR CONDITION - WINDSHIELD WIPER SYSTEM

1. Inspect wiper blade f o r s e c u r i t y , condition, and wear. Replace damaged

and d e t e r i o r a t e d blades.

2. Inspect wiper arm f o r s e c u r i t y and condition. I f wiper arm i s loose,

remove lockwire from clamping screw; t i g h t e n clamping screw and secure
with new lockwire.

3. Check pressure of wiper blade on windshield; a d j u s t t e n s i o n i n accordance

with Para 803-12.

4. Check stow p o s i t i o n of wiper blade. In t h e stow p o s i t i o n t h e wiper blade

must r e s t p a r a l l e l t o t h e c e n t e r post of t h e cabin s t r u c t u r e . The
clearance between blade and c e n t e r post must be approx. 30 nun. I f
necessary, c o r r e c t stow p o s i t i o n by r e l o c a t i n g t h e wiper arm on t h e wiper
s h a f t o r by r o t a t i n g t h e wiper blade.
5. Inspect converter housing f o r cracks and l o s s of grease i n v i c i n i t y of
t h e wiper s h a f t , worm and housing assembly, and Cover p l a t e . Replace
converter a s necessary.
6. Inspect motor and converter f o r s e c u r i t y . I f necessary, remove lockwire
from a t t a c h i n g screws, t i g h t e n a t t a c h i n g screws, and secure with new
lockwire .
7. Inspect motor, converter, and bracket f o r corrosion and damaged s u r f a c e
p r o t e c t i o n . Touch up corroded a r e a s and damaged s u r f a c e p r o t e c t i o n a s
necessary.
8. Inspect f l e x i b l e d r i v e s h a f t f o r e x t e r n a l damage and check t h a t both
union n u t s a r e properly lockwired.
9. Inspect e l e c t r i c a l connections f o r mechanical s e c u r i t y and condition.

803 - 5 FUNCTIONAL TEST - WINDSHIELD WIPER SYSTEM

General
- To ensure smooth operation of t h e wiper during t h e f u n c t i o n a l t e s t ,
continuously Spray t h e windshield with water o r l i f t wiper arm c l e a r of
windshield.
- Engage e x t e r n a l power supply. Place b a t t e r y switch 16P located on t h e r i g h t
s i d e of instrument panel i n BAT OFF/EPU ON p o s i t i o n .
- Depress 1ME WIPER c i r c u i t breaker on instrument panel.

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1. P l a c e 2ME wiper s w i t c h i n ON p o s i t i o n . The wiper must sweep a c r o s s t h e

e n t i r e c l e a n i n g a r e a without i n t e r r u p t i o n .

2. P l a c e 2ME wiper s w i t c h i n mid-position. The wiper must s t o p where it i s .

CAUT I O N D0 NOT HOLD THE 2ME WIPER SWITCH I N THE PARK

POSITION FOR MORE THAN 3 SECONDS OVER A 10-MINUTE
PERIOD BECAUSE THE 3ME DROPPING RESISTOR
WILL OVERHEAT.

3. P l a c e and h o l d 2ME wiper s w i t c h i n t h e PARK p o s i t i o n . The wiper must move

t o t h e stow p o s i t i o n p a r a l l e l t o t h e c e n t e r p o s t and come t o rest t h e r e .
4. Release 2ME wiper s w i t c h and p u l l o u t 1ME c i r c u i t b r e a k e r .

5. Remove e x t e r n a l power s u p p l y from h e l i c o p t e r .

803 - 6 Removal - motor

1. Make Sure t h e wiper arm i s i n t h e stow p o s i t i o n , t h e n p u l l o u t t h e 1ME
c i r c u i t breaker.
2. Remove forward a c c e s s door.

3. Remove f l o o r i n g m a t e r i a l on c o p i l o t ' s s i d e .
4. Disconnect f l e x i b l e d r i v e s h a f t (10, f i g . 803-3) f rom motor by unscrewing
and removing union n u t ( 2 6 ) .

5. Disconnect bonding jumper (24) from motor.

6. Remove screws ( 2 8 ) while a s s i s t a n t s u p p o r t s t h e motor.
7. Remove e l e c t r i c a l c o n n e c t o r (27) from motor.

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803 - 7 Installation - motor

1. Engage e x t e r n a l power supply ( r e f e r t o Chapter 900).

2. I n s t a l l connector .(27, f i g . 803-3) and lockwire.

3. Have t h e a s s i s t a n t Support t h e motor i n i t s mounting p o s i t i o n on t h e

underside of t h e f r o n t f l o o r p l a t e ; s e c u r e it w i t h screws (28) and
i n s t a l l lockwire.

4. Connect bonding jumper (24) .

5. Depress 1ME c i r c u i t b r e a k e r . Move 2ME wiper s w i t c h t o PARK p o s i t i o n and
h o l d it t h e r e u n t i l motor s h u t s down.

6. Connect f l e x i b l e d r i v e s h a f t (10) t o motor w i t h union n u t (26) and s e c u r e

with lockwire.

7. Perform f u n c t i o n a l test i n accordance w i t h P a r a 803-5.

8. Replace f l o o r i n g m a t e r i a l ; i n s t a l l forward a c c e s s door.

803 - 8 Removal - converter

1. Remove instrument p a n e l f a i r i n g , a s ' r e q u i r e d .

2. Loosen clamping screw (18, f i g . 803-3) and remove b o l t (19) with washer
(20).
3. Remove wiper arm (22) from wiper s h a f t .

4. Unscrew and remove union n u t t o d i s c o n n e c t f l e x i b l e d r i v e s h a f t (10) from

c o n v e r t e r (11).

5. With t h e a s s i s t a n t holding t h e j o u r n a l box ( 1 7 ) , unscrew n u t (13) from

t h e j o u r n a l box. Remove j o u r n a l box and o u t e r rubber s p a c e r ( 1 5 ) .
6. Remove screws ( 5 ) w i t h washers (6, 7 ) , and screws ( 8 ) with washers ( 6 )
from c e n t e r p o s t , and remove b r a c k e t (12) t o g e t h e r with c o n v e r t e r .

7. Remove i n n e r rubber s p a c e r ( 1 5 ) , t a b washer ( 1 4 ) , and n u t (13) f rom wiper

shaft .

8. Remove screws ( 9 ) with washers ( 6 ) and d e t a c h c o n v e r t e r from b r a c k e t .

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803 - 9 I n s t a l l a t i o n - converter

1. Turn c o n v e r t e r d r i v e s h a f t t o l o c a t e c o n v e r t e r i n stow p o s i t i o n .

2. Depress 1ME c i r c u i t b r e a k e r . Hold 2ME wiper s w i t c h i n PARK p o s i t i o n u n t i l

motor s t o p s .

3. Secure c o n v e r t e r t o b r a c k e t (12, f i g . 803-3) w i t h screws ( 9 ) and washers

(6).
4. I n s t a l l n u t ( 1 3 ) , new t a b washer (14). and i n n e r rubber s p a c e r ( 1 5 ) on
wiper s h a f t .

5. Secure c o n v e r t e r assembly t o t h e windshield c e n t e r p o s t with screws

( 5, 8 ) and washers (6, 7 ) .

6. I n s t a l l j o u r n a l box ( 1 7 ) and o u t e r rubber s p a c e r (15) on wiper s h a f t .

With t h e a s s i s t a n t h o l d i n g t h e j o u r n a l box, screw n u t ( 1 3 ) a g a i n s t t h e
j o u r n a l box; bend t a b washer ( 1 4 ) .
7. S e a l j o i n t between t h e j o u r n a l box and shaf t s l e e v e with s e a l i n g compound
(CM 6 6 2 ) .

8. Loosen nut (1) and a d j u s t wiper b l a d e s o t h a t t h e stow p o s i t i o n i s

p a r a l l e l t o and approx. 30 rnm from t h e c e n t e r p o s t . Locate wiper arm on
wiper s h a f t and t i g h t e n clamping screw ( 1 8 ) and n u t (1).
9. I n s t a l l washer ( 2 0 ) and b o l t (19) .

1 0 . Connect f l e x i b l e d r i v e s h a f t (10) t o c o n v e r t e r and s e c u r e with lockwire.

11. Perform f u n c t i o n a l test i n accordance with p a r a 803-5.

1 2 . Check p r e s s u r e of wiper b l a d e on windshield; i f necessary, a d j u s t

p r e s s u r e i n accordance with Para 803-12.

1 3 . I n s t a l l lockwire on clamping screw ( 1 8 ) and b o l t ( 1 9 ) .

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803 - 10 Replacement - wiper p l a d e

1. L i f t wiper arm (22, f i g . 803-3) from i t s stow p o s i t i o n and h o l d it c l e a r
of windshield by i n s e r t i n g a p i n (2.5 mm d i a m e t e r ) i n b o r e h o l e (23) i n
t h e arm channel.
2. Remove n u t (1) with washer ( 2 ) and d e t a c h wiper b l a d e .

3. I n s t a l l new wiper b l a d e and a l i g n with t h e windshield c e n t e r p o s t .

4. Secure wiper b l a d e t o wiper arm with n u t (1) and washer ( 2 ) .

5. Remove p i n and lower t h e wiper b l a d e onto windshield. V e r i f y t h a t t h e

wiper b l a d e i s p a r a l l e l t o t h e windshield c e n t e r p o s t ; a d j u s t b l a d e
p o s i t i o n a s necessary.

803 - 11 Replacement - flexible drive shaft

NOTE Replace f l e x i b l e d r i v e s h a f t with windshield wiper i n t h e

stow p o s i t i o n .

1. Remove instrument p a n e l f a i r i n g a s r e q u i r e d , and remove forward a c c e s s

door .
2. Disconnect t h e f l e x i b l e d r i v e s h a f t ( 1 0 , f i g . 803-3) from motor and from
c o n v e r t e r by unscrewing union n u t s .
3. Connect and s e c u r e new f l e x i b l e d r i v e s h a f t .
4. Perform f u n c t i o n a l t e s t with wiper arm h e l d c l e a r of t h e windshield
( r e f e r t o Para 803-5).

803 - 12 Adjustment - p r e s s u r e of b l a d e on windshield

1. At.tach s p r i n g s c a l e t o t h e measuring p o i n t ( f i g . 803-3) on wiper arm.

2. The wiper b l a d e must d e t a c h from t h e w i n d s h i e l d with p u l l i n g f o r c e of

15-17 N . I f n e c e s s a r y a d j u s t t h e p r e s s u r e of t h e b l a d e on t h e windshield
a s follows:

- To d e c r e a s e t e n s i o n on blade, t u r n p r e s s u r e a d j u s t i n g screw (21)

clockwise.

- To i n c r e a s e t e n s i o n on blade, t u r n p r e s s u r e a d j u s t i n g screw (21)

counterclockwise.

Operate wiper f o r one minute on wet w i n d s h i e l d and then check b l a d e

tension; readjust blade tension a s necessary.

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Fig. 803-1 Windshield wiper system - wiring schematic configuration I

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INSTRUMENT PANEL

V
-
Y H H 2VED
~
2 VEd
.

b
I A 4 MEa
A B C

4ME

'1 a A
t

LL. WlPER MOTOR 1

Wiper s w i t c h shown i n stow p o s i t i o n

F i g . 803-2 Windshield wiper system - w i r i n g schematic

C o n f i g u r a t i o n I1
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DETAIL C
28

Blade pressure measuring point

Nut Windshield
Washer Journal box
free Clamping screw
Wiper blade Bolt
Screw Washer
Washer Pressure adjusting screw
Washer Wiper arm
Screw Bore
Screw Bonding jumper
Flexible drive shaft Motor
Converter Union nut
Bracket Electrical connector
Nut Screw
Tab washer Front floor plate
Rubber spacer Protective resistor

Fig. 803-3 Windshield wiper system

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