Section IV. MAINTENANCE - TM-5-6350-262-14-10035

CHART 7-1. Troubleshooting Chart (Cont.).

Step

Symptom

Procedure

Corrective Measures

4. (Cont.)

RANGE control setting of 1 is not off but merely

substantially reduced range and lower noise

reduced range and lower noise from local

turbulence effects.

b. If the fluctuations or excessive offset (greater than

0.3 V above or below reference) are only in one

direction and are present when the transmit leads

are removed from terminals 1 and 2 of TB2 in

the processor, the problem is ultrasonic noise

or radio frequency interference (RFI).

Check for machinery noise, hissing steam or

air pipes, and radio frequency transmitter.

Check all conduit grounds and conduit

mechanical connections for tightness along

with system chassis grounds and signal

lead shield grounds.

Section IV. MAINTENANCE

(7)

Using a short length of 7/8 inch

7-9. Transducer Removal and Replacement

diameter wooden dowel against the screened end of the

Procedure

transmit transducer press the transducer and deflector

NOTE

(phenolic ring) out of the plastic support.

Both the transmit transducer (white dot)

(8) Unplug the 8 inch long lead from the

and the receive transducer (blue dot) are

rear of the transmit transducer.

suspended by plastic supports which

b. Transmit Transducer Installation Procedure.

also provide a mounting surface for the

The spare transmit transducer is identified by a white

pc board.

The plastic support

dot on the outer edge of the screened end of the

associated with the transmit transducer

transducer.

has a white dot on it and the plastic

(1)

Mate the screened end of the

support associated with the receive

transducer with the rear of the round sleeve portion of

transducer has a blue dot on it Always

the plastic transducer support. Place the jack end of the

maintain the color dot relationship

between the transducers and the plastic

transducer against a firm surface and press the top end

supports.

of the plastic sleeve portion with the hand palm until the

a. Transmit Transducer Removal Procedure. The

transducer ridge seats firmly against the plastic support.

transmit transducer is identified by a white dot, 8 inch

Press the deflector (phenolic ring) into the plastic

long attaching lead and it is located adjacent to the

support and against the transducer screen.

enclosure conduit entrance(s) (fig. 1-1).

(2) Plug the 8 inch long lead into the

(1) Tag, identify and remove the leads

transmit transducer jack.

attaching to terminal board TB1.

(3) Secure the transmit transducer and

(2)

Disconnect the transmit transducer

plastic transducer support to the enclosure using four 4

(white dot) and the receive transducer (blue dot) red and

x inch long flat head sheet metal screws, two through

blue leads along with the black chassis ground lead from

the rear of the enclosure and one through each side of

the pc board.

the enclosure (fig. C-3).

(3) Remove the three sheet metal screws

(4) Secure the enclosure to the mounting

securing the pc board to the two plastic transducer

surface and the conduit clamps that were temporarily

supports (fig. C-3).

loosened.

(4) Remove the two 4 x inch long flat

(5) Secure the pc board to the transducer

head sheet metal screws that thread through the sides

plastic supports using three 4 x inch long pan head

of the enclosure and into the plastic transmit transducer

screws (fig. C-3).

support (fig. C-3).

NOTE

(5)

Remove the enclosure mounting

The RANGE control end of the pc board

hardware and the necessary conduit clamps that will

oriented

toward

the

transmit

permit removing the transceiver enclosure a sufficient

transducer (white dot) and the Q1 Q2

distance away from the mounting surface to allow

component end of the pc board is

removal of the final two 4 x inch long flat head sheet

adjacent to the receiver transducer (blue

dot) (fig. 1-1).

metal screws through the rear of the enclosure into the

transducer plastic support.

(6) Connect the transmit transducer (white

(6) Remove the two flat head sheet metal

dot) red and blue leads to their respective terminals

screws from the rear of the enclosure and the plastic

adjacent to the RANGE control.

support with the transmit transducer attached.

7-57-5