A-B-B Teach Pendant Troubleshooting: Common Issues and Fixes

By Vicpas Industrial Automation Experts | Published: November 24, 2025

As a leading global supplier with over 15 years specializing in A-B-B robot spare parts and repair, Vicpas has helped thousands of factories minimize downtime. This guide compiles the most complete, real-world-tested solutions for A-B-B Teach Pendant (FlexPendant) problems.

Need parts immediately? Click here for A-B-B Teach Pendant parts — touch screens, membranes, cables, emergency stop switches — 365-day warranty + 24h worldwide shipping.

Why A-B-B Teach Pendant Issues Happen and How to Spot Them

According to the official A-B-B IRC5 Troubleshooting Manual and thousands of real cases, more than 80 % of FlexPendant failures fall into the four categories below — almost all of which can be solved quickly with the right steps.

Issue 1: Stuck on Boot Screen / Boot Failure

One of the most frustrating problems is when the FlexPendant gets stuck on the boot screen or freezes indefinitely at “Starting application”.

Causes

• Corrupted TPU image or flash disk from power interruptions
• Loose internal connections (especially display ribbon cable)
• Firmware mismatch after failed updates

Official A-B-B Recommended Fixes

1. Power cycle the entire system (30 seconds off)
2. Press and hold Stop + P1 (and enabling device) while powering on → forces complete image reload
3. Wait 5–12 minutes for completion
4. Check event log for remaining alarms

Issue 2: Frozen on “Connecting to Controller” or Communication Failures

Your A-B-B Teach Pendant powers on but freezes at “Connecting to Controller,” preventing any robot interaction. Community discussions highlight this as a frequent post-commissioning problem.

Causes

• Faulty network cables or loose connections between pendant and IRC5 controller
• Main computer module failure or SD card errors in the host
• Safety chain interruptions triggering alarms like 20240 (emergency stop)

Step-by-Step Fixes

1. Hard Reset: Press the small reset button on the pendant’s back (pinhole) while controller runs, or unplug/replug the cable
2. Ethernet Verification: Inspect LEDs — green pulsing indicates healthy link. Swap cables and test ports
3. B or P Startup: Attempt “B” (basic) or “P” (partial) boot via controller panel. Avoid “I” startup unless factory reset is desired
4. Alarm Reset: Clear 10012/10013 by ensuring all safety devices are closed and switching to Motors ON

For persistent issues, our Vicpas repair kits include high-durability Ethernet cables (3HAC047665-002) — browse catalog.

Issue 3: White Screen / Blank Display

A blank white startup screen on your A-B-B Teach Pendant, despite the robot running smoothly, screams display hardware trouble. Forums pinpoint this to internal ribbon cable shifts, especially after handling mishaps.

Causes

• Loose or unseated display ribbon cable in the SxTPU board
• Backlight power-saving mode or driver calibration errors
• Overheating or ESD damage (always use wrist straps per A-B-B safety guidelines)

Step-by-Step Fixes

1. Reseat Connections: Power off, open the pendant (if comfortable), and gently push the ribbon cable back into its slot. Secure with Kapton tape
2. Power and Backlight Check: Verify 24 V supply from DSQC 662; reset breaker F5 if voltage low
3. Firmware Reload: Use P1 + Stop method to reflash
4. Test Swap: Connect a known-good pendant to confirm controller health

Issue 4: Touchscreen Unresponsive or “Robotbootappl.exe” Crash

Touch inputs ignored or crashes like “Robotbootappl.exe has stopped working” are common.

Causes

• Dust on acoustic reflection stripes blocking signals
• Faulty touch matrix, control card, or signal lines
• Software crashes from incompatible drivers or high CPU loads

Step-by-Step Fixes

1. Clean reflection stripes with soft cloth (no liquids)
2. Recalibrate touch in Settings → Calibration
3. Reboot with P1 + Stop to reinstall image
4. Replace digitizer if physically damaged — Vicpas supplies pre-calibrated units

When to Call in the Pros: Advanced Repairs for Stubborn A-B-B Teach Pendant Issues

If DIY steps fail, deeper problems like PCB damage, battery failures, or bus communication errors may lurk. Professional services handle these with SMD/THT component swaps and simulated robot testing.

While options like K+S Services or Neethsel HK excel in screen and power repairs, Vicpas stands out with A-B-B-specific expertise: We source genuine-compatible parts globally, ensuring 100 % uptime compatibility.

Explore our Teach Pendant solutions for everything from emergency stop switches to full refurbishments — backed by our commitment to quality and fast delivery.

Final Tips for Preventing A-B-B Teach Pendant Downtime

• Routine Maintenance: Clean screens monthly, secure cables, and update firmware quarterly.
• Safety First: Always release the enabling device if malfunctions occur, and work in manual mode within arm reach.
• Backup Plans: Keep spare parts handy — Vicpas ships worldwide in 24 hours.

References & Further Reading

• FlexPendant DSQC 679 stuck on booting – RobotStudio Forum
• Robotbootappl.exe crashed – Robot-Forum
• Frozen on “Connecting to Controller”
• White startup screen – ribbon cable fix
• P1+Stop recovery method
• ABB Official IRC5 Troubleshooting Manual (PDF)
• K+S Services – ABB Teach Pendant Repair
• Neethsel HK – Industrial Teach Pendant Repair

Vicpas: Empowering Industrial Automation with Precision and Reliability.