Identifying a Faulty On-Board IS Module


With the introduction of On-Board IS and its two electronic modules: CPC Module (Communication and Power Conditioning) and AMC Module (Analog and Measurement Control), identifying which module is the cause for a cryopump failure can be a challenging task. This white paper will provide a basic understanding of the functionality contained in each module and troubleshooting tips to help facilitate the identification of the faulty module.

CPC Module Functionality:

  • Communication interface for the tool, On-Board Network and AMC module
  • Generates 3 phase voltage for the variable speed motor and controls the speed of the motor from 44-144 RPM
  • Contains the application code for controlling and monitoring valves, heaters, temperature readings, temperature control, regeneration and Heater Fault Interrupt (HFI)
  • Provides 208 VAC to power the AMC Module

AMC Module Functionality:

  • Receives commands from the CPC to perform the following:
    • Reads the 1st and 2nd stage temperatures
    • Reads the TC Pressure
    • Perform temperature control:
      • 1st stage temperature for PVD Cryopumps
      • 1st and 2nd stage temperature control for Implant Cryopumps
    • Store/retrieve User and Factory programmable valves in NVRAM
  • Performs the following functions:
    • Excitation current for reading the 1st and 2nd stage temperature sensors and TC Gauge
    • Controls the heater voltage for the 1st and 2nd stage heaters
    • Provides 24VDC for enabling the cryopump valves
    • Senses leakage currents through the 1st and 2nd stage heaters
    • Provides 24VDC to power the CPC module
    • Stores the following into NVRAM
      • Diode curves for the 1st and 2nd stage temperature sensors
      • Cryopump serial number
    • Senses motor temperature
    • Senses gate valve position and control for Implant Cryopumps

Module Interface Schematic:

Identified in Figure 1 is a block diagram of the CPC/AMC Modules and IntelliPurge PCB. The diagram identifies the interfaces between the CPC/AMC Modules and IntelliPurge PCB connections to the cryopump and user interface. This diagram in conjunction with Tables 1-3 are an excellent source of identifying a potentially defective module.

Figure 1 - On-Board IS Module Interface Connections

Table 1 - CPC Module LED Status


Status LED I Motor Power and Temperature Control Status
OFF Motor is OFF
GREEN Motor ON - Temperature Control is enabled
AMBER Motor OFF - Temperature Control is not enabled


Status LED II Regeneration Status
OFF Regeneration is Idle
GREEN Full Regeneration is executing
AMBER Fast Regeneration is executing


Status LED III CPC Power, Communication and HFI Status
OFF No Power to the CPC
SOLID GREEN CPC Power ON, No Network Communications
BLINKING GREEN CPC Power ON, Network Communicating
SOLID AMBER CPC Power ON, No Network Communications, HFI Fault
BLINKING AMBER CPC Power ON, Network Communicating, HFI Fault


Table 2 - IntelliPurge LED Status


LED IntelliPurge
Power Green Power On - Off No Power
Enabled Green when UPS is fully Charged
Service Red when Service is Required


Table 3 - Troubleshooting Guide


On-Board IS Module Troubleshooting Guide
Problem Possible Cause/Symptom Possible Corrective Action
Temperature Control not working 1. Status LED I is Amber
2. Status LED III blinking or Solid Amber
3. Status LED I & III are Green
4. Heater not working
1. Enable Temperature Control
2. Reset HFI Fault
3. Power Cycle cryopump
a. Replace AMC Module
4. Replace AMC Module
a. Replace Cryopump
Purge/Rough/Vents values not working 1. No 24VDC 1. Power Cycle Cryopump
a. Replace AMC Module
Motor will not turn ON 1. Status LED I is OFF
a. Faulty CPC Module
b. Faulty Motor
1. Check Input AC Power
a. Replace CPC Module
b. Replace Cryopump
Remote Display will not turn ON 1. No 5VDC 1. Power Cycle Cryopump
a. Replace CPC Module
Cryopump is not recognized by the Tool Controller 1. On-Board Network Problem 1. Verify Cryopump Network Address is set properly
a. Power Cycle Cryopump
b. Replace CPC Module
Temperature reading “OPN” or “SHO” 1. Cable disconnected
2. No excitation current
1. Verify cable is connected
2. Power Cycle Cryopump
a. Replace AMC
CPC LED’s I, II, II are OFF 1. No AC Input Power to the CPC
2. No DC power to the CPC
1. Verify 208VAC input power
2. Replace AMC Module
Gate Valve Failure 3. Cable disconnected
4. IntelliPurge error
5. AMC error
3. Verify cable is connected
4. Replace Cryopump
5. Replace AMC Module

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