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EPC Communication Failure or the Mass Spectrometer has lost signal - WKB9414

Article number: 9414


  • MassLynx status shows instrument not present or embedded system is not responding, system will run in standalone mode
  • Mass range stuck at 0–200000 Da in MassLynx
  • No signal , Blank spectrum and TIC in UNIFI
  • Tune page freezes or some of the features are greyed out or unable to switch MS into Operate
  • Pinging EPC or IP address for MS gives 'request timed out'
  • Hyperterminal is giving following message:
  • (ACQSERVERACQTHREAD): Disabled recurring reports
    Failed to reply to client eventId: 15
    [36590988] (INST_MON): Instrument Monitor: Client has shutdown
    [36590988] (ACQSERVERACQTHREAD): Socket send failed, bytes sent = 0, data sFailed to reply to client eventId: 15
    Failed to reply to client eventId: 15
    Failed to reply to client eventId: 15
    ize = 256. - File: D:/cygnus/InstrumentControl/ExternalSources/message.c, line: 537
    [36590988] (ACQSERVERACQTHREAD): 4101_server: header send failed - File: D:/cygnus/InstrumentControl/ExternalSources/message.c, line: 2126
    Failed to reply to client eventId: [15
    36Failed to reply to client eventId: Faile25d to reply to clie
    nt eventId: 515
  • Pinging is successful on other system component
  • No response with Hyperterminal
  • Ping EPC command responds correctly as expected. Communications still possible via Hyperterminal.
  • Instrument vented


  • MassLynx
  • Xevo G2
  • Xevo G2-S
  • Xevo G2-XS 
  • SYNAPT G2-Si
  • QToF Prem
  • Xevo TQ MS
  • Xevo TQ-S
  • XevoTQ-XS


EPC lost communication


  1. Confirm that all the network hardware from Host PC to the instrument are connected correctly and powered-up
  2. Eliminate any LC or network hardware by plugging a cross-over cable directly between host PC and EPC.
  3. Exit MassLynx and reboot the host PC or in the case of UNIFI control take the Instrument System offline.
  4. Set Pump Override switch on back (Top switch) into Override position (Down) on Xevo series and on Synapt series place pump Override switch to Right for Override position. On QToF Prem, place Pump Overrride switch down for Override position
  5. Turn off Electronics switch  on Xevo series and on Synapt series and QToF Prem turn off both EPC and Electronics breakers.
  6. Power off the external EPC (note: Most effective to directly power off using power supply switch on BACK of EPC) for Xevo ToF/QtoF G2
  7. Wait 2 minutes. Then set Electronics switch into ON (Up) position on Xevo series and on Synapt series turn on both EPC and Electronics switches.
  8. Switch the Power toggle on back of external EPC back ON.
  9. Wait 2-3 minutes for communications to be established.
  10. On desktop in RUN window, type "ping -t epc", make sure epc communicating
  11. Open Tune Page (or Instrument Console in UNIFI), there should be a Red Warning message reminding that Pump Override is in effect
  12. Switch the Pump Override switch back to the Control/Auto (Up) position or (Left) position on Synapt series


Failure of the Power Module PCB which causes loss of power to instrument electronics.  EPC however is powered directly from the Power Distribution Unit via Electronics and EPC breakers.  Result is communication to EPC, but no communication from EPC to instrument electronics (Lens control PCB). Please refer to Power module Tech Ref file for expected voltage outputs.

Power module PCB  part # 

Synapt  700003302 and all other Synapt series 700004980

Xevo ToF/QToF series 700004459

Xevo  TQ MS/S/XS 700004173


Partial Hyperterminal boot log below showing repeating error:


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