Symptom: Alarm 107 EMERGENCY STOP. Alarm 820 COUNTER BALANCE FAILURE. The spindle head drops with EMERGENCY STOP on.
Possible Cause: There is low nitrogen pressure in the conterbalance system. There is low oil level in the counterbalance system.
Check for leaks on the top of the cylinder.
If there is no leak, recharge the nitrogen: Remove the cap  from the Shrader valve. Connect the Charge / Discharge kit (P/N 35-4050A)  to the Shrader valve . Use the "System Pressure" chart at the beginning of the document for the correct pressure.
If the cylinder leaks oil: Go to Section 3.
Symptom: Alarm 107 EMERGENCY STOP or Alarm 820 COUNTER BALANCE FAILURE
Possible Cause: The pressure switch circuit does not operate correctly.
Disconnect the pressure switch cable  from the pressure switch . 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. If the alarm does not reset, go to diy.haascnc.com to troubleshoot the pressure switch cable .
Symptom: The cylinder leaks oil.
Possible Cause: There is contamination in the oil. The hydraulic cylinder is misaligned.
Any leak in the hydraulic counterbalance system means the system is damaged , 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 on diy.haascnc.com. 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.