Service Home Hydraulic Counterbalance - Troubleshooting Guide
Last updated: 11/04/2024

Hydraulic Counterbalance - Troubleshooting Guide

Components

  1. Hydraulic Tank: mounted upside-down on the column of the machine. It holds the hydraulic oil and pressurized nitrogen.
  2. Hydraulic Cylinder: relieves vertical force from the spindle head on the verticle axis servo motor.
  3. Pressure Gauge: shows the system pressure.
  4. Hose Outlet: connection point for the hydraulic hose. The other end connects to the 90° fitting [8] on the hydraulic cylinder.
  5. Pressure Manifold: connected to the hydraulic tank.
  6. Pressure Switch: tells the control when the pressure is low.
  7. Schrader Valve: allows you to add or remove pressure.
  8. 90° Fitting: connection point for the hydraulic hose. The other end connects to the hose outlet [4] on the tank.
  9. Threaded Rod End: connects to the spindle head bracket.

System Pressure Chart

Model Built After Pressure Built After Pressure Built After Pressure
    PSI BAR   PSI BAR   PSI BAR
EC-1600/2000/3000 3/15/2004 1000 70 9/13/2004 550 38 6/14/2005 800 55
EC-630 3/21/2006 800 55            
HS-1 10/30/1997 600 51            
HS-3/4/7 6/5/1998 1150 79 6/18/1999 1200 83 2/29/2000 1250 86
VB-1 6/5/1998 1550 107            
VF-3/4 (VCE 1000/1250) 4/28/1995 1150 79            
VF-5 XRT 10/8/2004 750 52            
VF-5, VM-3, VF-3YT (VCE 1300) 7/21/1998 950 66 10/14/1998 875 60      
VF-5/50, VF-3YT/50 (VCE 1300) 7/21/1998 1100 76            
VF-6/7/10/12 - 50 (VCE 1600, 2000, 3000) 10/30/1997 1150 79            
VF-6/7/10/12 (VCE 1600, 2000, 3000) 10/30/1997 750 52            
VF-8/9/11 - 50 (VCE 1600, 2000, 3000) 7/21/1998 1550 107            
VF-8/9/11 (VCE 1600W, 2000W, 3000W) 10/30/1997 750 52            
VF-O/OE/EXT/1/2 (VCE 475/500/550/700/750) 4/28/1995 750 52            
VR-8/9/11 10/30/1997 1800 124 7/21/1998 1100 76 10/14/1998 1025 71
VS-1/2/3 2/29/2000 1250 86            
VTC 5/4/2002 1150 79            
HDC-3-5AX 2/1/2024 1050 72            
  All pressures should be at the top of travel (+50, -0 psi) (+3, -0 bar)

Symptom Table

Symptom Possible Cause Corrective Action

Alarm 107 EMERGENCY STOP

Alarm 820 COUNTER BALANCE FAILURE

 There is low nitrogen pressure in the conterbalance system. Check for leaks on the cylinder and recharge the tank with nitrogen.
The pressure switch circuit does not operate correctly. Troubleshoot the wiring and switches.
Leaking high pressure counterbalance gauges due to a vendor quality issue. Replace leaking pressure gauge. See Leaking Pressue Gauge section below. Refer to: HSG-N 11-04-2024
The spindle head drops with [EMERGENCY STOP] on. There is low nitrogen pressure in the conterbalance system. Check for leaks on top of the counterbalance cylinder.
There is low oil level in the counterbalance system. Check for an oil leak on the cylinder.
The cylinder leaks oil. There is contamination in the oil. Check for the cause of contamination.
The hydraulic cylinder is misaligned. Check for the cause of the leak.
Bimba brand makes noise. The bimba brand has lower rod wipers to prevent contamination from the bottom cylinder, these rod wipers may make noise.  This is a normal noise from this brand, do not replace counterbalance cylinders

Nitrogen Pressure

Corrective Action:

Check for leaks on the top of the cylinder.

If there is no leak, recharge the nitrogen: Remove the cap [1] from the Shrader valve. Connect the Charge / Discharge kit (P/N 35-4050A) [2] to the Shrader valve [3]. Use the "System Pressure" chart at the beginning of the document for the correct pressure.

If the cylinder leaks oil: Go to Section 3.

Pressure Switch

Corrective Action:

Disconnect the pressure switch cable [1] from the pressure switch [2]. Make sure that there is no contamination on the connectors. Use a jumper to connect the pins on the cable. If the alarm resets, the pressure switch is at fault. Refer the VMC - Hydraulic Counterbalance - Pressure Switch - Replacement procedure.

If the alarm does not reset jump at the I/O board.  If the alarm resets replace the pressure switch cable [1].  If the alarm does not reset refer to the CHC - I/O PCB - Troubleshooting Guide.

 

 

Oil Leaks

Corrective Action:

Any leak in the hydraulic counterbalance system means the system is damaged [1], and must be replaced. Both the hydraulic cylinder and the hydraulic tank must be replaced together to avoid oil contamination.

For replacement instructions, refer to the document VMC - Hydraulic Counterbalance - Replacement. The replacement instructions include information on how to correctly align the cylinders. The new cylinder(s) must be correctly aligned to avoid damaging the new system and cause another leak.

Leaking Pressure Gauge

Corrective Action:

Verify the type of pressure gauge on the counterbalance tank. If the faulty gauge is present replace with a good gauge. (PN: 52-0014)

 Note: The gauges have different back-up nuts; the failing gauges have a smaller back-up nut while the good gauges have a wider back-up nut. The failing gauges also have a clear o-ring while the good gauges use a black o-ring.

Recharge the counterbalance tank. Use the "System Pressure" chart at the beginning of the document for the correct pressure.

If the cylinder leaks oil: Go to Section 3.