Section II. DRIVE CONTROL TESTS AND ADJUSTMENTS

TM 10-3930-631-34

mature and field windings back to the negative side of

horn (H1-2) through contactor panel terminal P6- 2 to

the battery.

terminal HY1-2 of the diode suppressor module. The

(2) A diode and resistor located inside the

path continues through the, hash filter inside the module

diode suppressor module, which are used to suppress

and out module terminal HY1-1 through contactor panel

voltage spikes, are wired in parallel with the emergency

terminal P6-8 to the positive side of the horn (H1-1).

cutout contactor coil. At the instant the coil is de-

(3) With the battery connected, key switch

energized, the path for induced current is from the

closed, and a normally open directional contact closed,

negative side of the coil to terminal HY1-4 of the diode

the hourmeter will operate. Current flows from the now

suppressor module. The path continues through the

closed directional interlock- contact (S3-2 or S4-2) to

diode and resistor inside the module and out terminal

terminal P6-5 of the contactor panel. From terminal P6-

HYl-9 to the positive side of the power steering coil.

5, current flows through the hourmeter and back to the

i. Horn and Hourmeter Circuits.

negative side of the battery.

(4) The hourmeter will also operate whenever

(1) Current flow for the horn is from the positive

the pump contactor coil is energized by the operation of

side of the battery through the power fuse, F1 15 amp

any of the parallel pump contacts. Current flows from

accessory fuse, contactor panel terminal P6-8 and the

the pump contactor coil (K3-1) to terminal HY1-3 of the

horn to the horn button. From the horn button, current

diode suppressor module, through a diode inside the

flows back to the negative side of the battery.

module, and out terminal HY1-5 of the module to

(2) Another hash filter, located in the diode

terminal P6- 5 of the contactor panel. From terminal P6-

suppressor module, is wired in parallel with the horn and

5, current flows through the hourmeter and from there

is used to suppress voltage spikes. When the horn

back to the negative side of the battery.

button is released and the horn vibrator is in the make

position, the path for induced current if from the negative

side of the

Section II. DRIVE CONTROL TESTS AND ADJUSTMENTS

will assure correct installation after check or test is

9-4. General

completed. After connecting wires or cables, make

a. Safety Precautions.

Observe the following

certain all connections are tight.

precautions throughout all tests and adjustments.

9-5. Preparation

(1) Always check battery polarity.

a. Disconnect the battery and discharge the

(2) Disconnect

battery

and

discharge

capacitors. Remove the cover over the contactor panel,

capacitors before taking resistance readings, performing

toe and floor plates, and the speed control box cover.

ground tests, or replacing components or modules.

Open the static panel compartment door, located on

Discharge capacitors as follows:

lower left side of lift truck, and carefully swing static

(a) Disconnect battery.

panel assembly to the full out position.

(b) Turn key switch to on position and depress

b. Check all fuses to ensure proper value and

horn button.

(3) Do not ground or short any heat sinks as

continuity.

they are integral parts of circuits. Never eliminate or

c. Inspect the lay of all cables, harness, and

modify heat sinks.

control wires to assure that there is no chafing of these

(4) Make certain battery is fully charged prior to

items against sharp edge of the equipment.

d. Inspect all terminals to assure that all wires and

any testing. Specific gravity reading at 80 F (27 C)

should be 1.265 to 1.290.

cables are properly crimped and all connections are tight.

(5) Check operation of any newly installed

e. Inspect speed control box to assure that

component or module to be certain problem has been

potentiometers and operating shaft are mounted

corrected.

securely.

(6) Do not wear jewelry such as wrist watches

f. Check the tightness of all mounting screws and

and rings, if possible, while performing tests and

nuts. Make certain there are no broken or missing

adjustments.

cotter pins and replace any broken or

missing

b. Identification. Always tag and identify location

lockwashers.

of wires and cables before they are disconnected from

g. Inspect the forward and reverse switch to

any terminals. Identification

assure

that

terminal

connections

are

tight.

9-8