What causes Haas alarm 702?

TSC probe cable damaged, pinched, or disconnected at the machine spindle or MOCON connection point. TSC probe battery depleted or probe internal electronics failure requiring probe replacement. MOCON board input circuit failure or damaged receiver channel for TSC signal processing. Electrical noise interference from VFD, spindle drive, or improper grounding affecting probe signal integrity. Incorrect TSC probe parameter settings in Setting 85 or Setting 86 causing communication protocol mismatch.

How do I fix Haas alarm 702?

1. Step 1: Verify TSC probe cable is securely connected at both the spindle drawbar area and the MOCON board connector, inspect for visible damage or wear 2. Step 2: Check TSC probe battery voltage using a multimeter if probe is battery-powered type, replace battery or probe if voltage is below 2.8V 3. Step 3: Access Diagnostics page and monitor TSC input signal status while manually triggering the probe stylus to confirm signal reaches MOCON 4. Step 4: Verify Settings 85 and 86 match the installed probe type and manufacturer specifications, consult Haas TSC installation manual for correct values 5. Step 5: Swap TSC probe cable with known good cable or temporarily bypass cable with direct connection to isolate cable versus probe failure 6. Step 6: If all external components test good, suspect MOCON board TSC input circuit failure and prepare to replace MOCON board or contact Haas Factory Outreach

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Haas Controller

Coolant · Intermediate · 15-30 minutes

Alarm 702

Haas Alarm 702 - Through Spindle Coolant Fault

Alarm 702 TSC Fault occurs when the NGC control activates the through-spindle coolant solenoid but the TSC pressure switch (typically input IN14) fails to close within the programmed timeout period. The control monitors this feedback to ensure adequate coolant pressure reaches the spindle before machining operations continue.

HaasCoolantIntermediate15-30 minutes

702

Haas Alarm 702 - Through Spindle Coolant Fault

TSC Fault

Root Cause Summary

Alarm 702 TSC Fault occurs when the NGC control activates the through-spindle coolant solenoid but the TSC pressure switch (typically input IN14) fails to close within the programmed timeout period. The control monitors this feedback to ensure adequate coolant pressure reaches the spindle before machining operations continue.

Safety

TSC disabled

Causes and Fixes

1
Check coolant tank level
Verify coolant tank is filled above minimum level mark. Low coolant allows air to enter the TSC pump intake.
Never run TSC system with low coolant as this will damage the TSC pump
2
Purge air from TSC lines
Access COOLANT menu and run TSC PRIME function to purge air from lines. Monitor pressure gauge during priming cycle.
Run TSC prime cycle 2-3 times if system has been sitting idle for extended periods
3
Verify TSC pressure switch operation
Go to DIAGNOSTICS > INPUTS and monitor IN14 (TSC pressure switch) while manually activating TSC to confirm switch closes when pressure builds.

DIY Feasiblehigh confidence

Call a technician if:

·TSC pump motor replacement required
·Control input card failure suspected
·Spindle internal coolant passages blocked

Prevention

Change TSC filter every 6 months
Use proper coolant mixture ratio
Run TSC prime cycle weekly
Monitor coolant contamination levels

Common Mistakes

Running TSC with low coolant tank
Ignoring gradual pressure loss
Using incorrect coolant concentration
Not priming system after coolant changes

Related Alarms

701 703 710

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Always verify with your machine manual or a certified technician before performing service procedures.