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Service Manual
Adjustments
Hydraulic displacement control (HDC) and electric displacement control (EDC) adjustment
Series 90 Pumps
W
Warning
The following procedure may require the vehicle/machine to be disabled (wheels raised off the ground,
work function disconnected, etc.) while performing the procedure in order to prevent injury to the
technician and bystanders. Take necessary safety precautions before moving the vehicle/machine.
Checking switch continuity
Servo pressure gauge port M4
G
0 - 50 bar [0 - 1000 psi]
B
9/16-18
12 N•m [9 lbf•ft]
t
1. Install a 50 bar [1000 psi] gauge in each of the two servo cylinder gauge ports (M4 and M5). Attach a
continuity checker to the terminals of the neutral start switch.
2. Energize the starter circuit, and start the prime mover.
3. While operating at normal speed and with the pump in its neutral (zero flow) position, note the
pressure reading on the gauges. Note this reading as the base pressure.
4. Slowly move the control handle in one direction while observing the pressure gauges and the
continuity checker. The switch must open before the pressure on either gauge increases more than 1
bar [15 psi] from the base pressure obtained at neutral.
5. Slowly move the control handle in the opposite direction. Again, The switch must open before the
gauge pressure increases more than 1 bar [14.5 psi] from base pressure.
6. Verify continuity again when the control is returned to neutral.
7. If the switch does not open at base pressure plus 0 to 1 bar [0 to 14.5 psi] in either direction, stop the
prime mover and readjust the eccentric plug as described in the previous section. If the pressure
difference is equal in each direction but greater than 1 bar [14.5 psi], loosen the switch lock nut and
turn the switch clockwise 1/12 turn (30°) to increase the sensitivity. Retighten the lock nut and
recheck pressure differences and continuity.
8. After verifying proper control and switch operation, stop the prime mover. Remove the continuity
checker and pressure gauges. Reinstall the servo pressure port plugs and reconnect the electrical
leads from the machine starter circuit to the NSS. Install and adjust, the external control linkage if
necessary.
The neutral adjustment is the only adjustment that can be made on hydraulic and electric displacement
controls. All other functions are preset at the factory.
520L0818 • Rev 0101 • August 2015
Servo pressure gauge port M5
G
0 - 50 bar [0 - 1000 psi]
9/16-18
B
12 N•m [9 lbf•ft]
t
P106 166E
39
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