Sea Tel USAT, Quick Start Manual

Field Service Procedure – Replacement Pol Pot Kit, USAT 

Page

2

of

7

Document No 

135929 Rev A

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Tel, Inc.  This document may not be reproduced or distributed in any form without prior written 

consent of Sea Tel, Inc.  

5.

Verify

the

Resistance

of

the

Pol

Pot:

The

polang

potentiometer

(pol

pot)

consists

of

an

internal

slider

as

well

as

a

clockwise

and

Ccounter

‐

clockwise

contact.

To

verify

the

resistance

of

the

pot

a

multi

‐

meter

can

be

used

to

measure

between

the

slider

and

one

of

the

wipers

while

rotating

the

shaft

through

its

range

and

verifying

the

0

–

5

ohms

is

outputted

correctly.

Disconnect

the

pot’s

reflector

harness

connector

from

the

pol

pots

connection.

Looking

down

onto

the

shaft

of

the

pot

rotate

it

clockwise

until

it

reaches

its

end

stop.

Now

measure

the

resistance

between

the

slider

and

the

counter

‐

clockwise

contact

(grey

cable,

pin

2

and

the

red

cable,

pin

3).

The

feedback

should

be

approximately

5k

ohms.

Now

slowly

rotate

the

shaft

of

the

pot

counter

clockwise,

the

reading

should

count

down

sequentially.

After

one

and

a

half

turns

the

pot

will

be

in

the

center

of

its

range

giving

a

resistance

of

approximately

2.5k

ohms.

Continue

to

rotate

the

pot

until

the

counter

clockwise

end

stop

(it

will

now

have

turned

through

all

3

rotations

of

its

range),

the

resistance

should

be

approximately

0

ohms.

Leaving

the

pot

at

its

counter

clockwise

end

stop

measure

between

the

clockwise

contact

and

the

slider

(the

grey

cable

pin

2

and

the

black

cable

pin

1).

The

resistance

should

be

reversed

from

the

previous

rotation,

reading

5

ohms.

Rotating

the

shaft

of

the

pot

clockwise

should

reduce

the

resistance

through

its

range

to

0

ohms.

Any

error

with

the

pot

not

giving

the

correct

resistance

is

an

indication

the

pot

is

defective

and

needs

replacing.