3024 Loss of hydraulic pressure.
Sheet 4 plug 2 pin-K
This error is detected through a loss of 24 volts on wire number 411 to the control, usually caused by the hydraulic pressure switch opening (mounted on the power-pack manifold). It sometimes occurs when a large volume demand is made on the hydraulic pump, e.g. tool-changing, Y axis counterbalance etc. 

a) Operate the 'Manual Hydraulic' switch to run the power-pack independent of the control and monitor the hydraulic pressure. If the hydraulic pressure is normal i.e. 700 PSI, check for 110 volts A.C.to wire number 180 on TB1 in the power distribution panel. If 110 volts is present at wire 180 refer to paragraph (d). If 110 volts are not present the pressure switch is faulty or needs adjustment; reduce the hydraulic pressure to 500 PSI and turn the pressure switch adjusting screw anti-clockwise until 110 volts are monitored on terminal 180. If this can't be achieved repair or replacement of the switch is necessary. 

b) If the hydraulic pressure is zero and the pump motor is running, check that the hydraulic dump valve (mounted on the power-pack manifold) is energised; if it isn't indicator fuse 1 in the power distribution panel is suspect and should be checked. If the valve is energised the pump-motor coupling or the pump is suspect; remove the inspection cover to gain access to the coupling. 

c) If the hydraulic pressure is low, adjust the pressure compensation valve on the side of the pump while monitoring the pressure. First unscrew the valve anti-clockwise slowly, decreasing the pressure; the minimum pressure should be about 400 PSI, then turn the adjustment screw slowly clockwise to increase the pressure 700 PSI. If the pressure doesn't increase sufficiently the compensation valve may be defective; dismantle the valve and check the condition of the 8mm diameter steel ball, if there's any sign of wear or pitting it should be replaced. Re-assemble the valve and again check the pressure; if 700 PSI then can't be achieved the hydraulic pump is suspect.

d) Turn the 'Manual Hyd' switch back to 'CNC' press the 'Reset' pushbutton and power-up the machine from the control. If the machine powers-up without a 3024 alarm refer to paragraph (e). If the 3024 alarm displays check for 24 volts D.C. on terminal 400. If there is no 24 volts present indicator fuse 4 in the PDP is probably faulty. If 24 volts are present on terminal 400 fit a link wire between terminals 400 and 411 in TB1 and retry. If the alarm persists switch-off the control and transpose the 'DI' boards situated in the lower rack to the left. Power-up the machine. If the fault disappears, or a different, unrelated error code shows-up, then the 'DI' board is faulty and a replacement is required. If the same error code persists switch-off the machine, remove plug 2 and check the continuity from pin-K to terminal 411. There may be a spare wire in the cable loom to utilize if wire 411 appears to be broken. If the wiring is O.K. the fault may be with the 'Watchdog' board (WD 50x) in the control or corruption of the memory. If another control is available the 'Watchdog' boards can be exchanged to test. If the memory is to be reloaded remember to punch-out programme and tool information first (although an up to date back-up tape should always be held).

e) Jog the Y axis in a +ve direction at maximum feedrate while monitoring the hydraulic pressure; if the pressure drops by 100 PSI or more Check that the accumulator pressure is set at 500 PSI and retry. If the pressure still drops turn the pump volume control screw if fitted (opposite side to the compensator) anti-clockwise no more than half a turn and retry. Pressure reduction now would indicate a faulty pump.