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Common PCBA Test Failures and How to Fix Them

Common PCBA Test Failures and How to Fix ThemBy SUNSOAR – Your Reliable PCB/PCBA Manufacturing Partner📍www.pcbsun.com | 📩 sales03@sunsoartech.com | ☎ +86 13632793113

In today’s highly competitive electronics industry, ensuring the quality and reliability of PCBA (Printed Circuit Board Assembly) is non-negotiable. Even with the most advanced equipment and processes, test failures remain a common challenge. Identifying these issues early—and knowing how to fix them—is key to reducing returns, maintaining customer trust, and avoiding costly delays.

In this post, we will explore the most common PCBA test failures, what causes them, and how to troubleshoot them effectively, drawing from SUNSOAR's years of hands-on manufacturing experience.

🔧 1. Solder Joint Failures

Symptoms: Open circuits, intermittent connections, or high resistance paths during In-Circuit Testing (ICT) or functional testing.

Root Causes:

  • Cold solder joints due to improper heat profile.

  • Insufficient solder paste or paste misalignment.

  • Contaminated pads or oxidation.

Fix:

  • Adjust reflow oven profile for proper heat distribution.

  • Verify stencil thickness and alignment.

  • Implement strict storage and handling protocols for components and bare PCBs.

⚡ 2. Component Misalignment or Tombstoning

Symptoms: Visibly skewed or lifted components, especially chip resistors and capacitors.

Root Causes:

  • Uneven solder paste deposit.

  • Asymmetric heating during reflow.

  • Excessive vibration or placement pressure.

Fix:

  • Use AOI (Automated Optical Inspection) post-placement.

  • Balance solder paste volume and ensure symmetrical pad design.

  • Review pick-and-place pressure settings and nozzle condition.

🔍 3. Open Circuits

Symptoms: Certain circuit paths not completing during ICT or continuity tests.

Root Causes:

  • Missing or cracked solder joints.

  • Damaged traces or vias during handling or fabrication.

  • Improper PCB layout or via design.

Fix:

  • Use X-ray inspection to detect hidden issues.

  • Verify design against IPC-A-600 standards.

  • Employ robust ESD-safe handling practices.

🔥 4. Short Circuits

Symptoms: Unexpected continuity between power and ground or signal lines; device heating up or not powering.

Root Causes:

  • Solder bridging during reflow.

  • Poor stencil design or excessive paste.

  • Component shift during reflow.

Fix:

  • Enhance stencil design with aperture reductions or home-plate shapes.

  • Use SPI (Solder Paste Inspection) for real-time feedback.

  • Clean and maintain reflow ovens to prevent contamination buildup.

🧲 5. Component Damage During Assembly

Symptoms: Non-functional components, burned ICs, or failed functional tests.

Root Causes:

  • Excessive heat during rework or soldering.

  • Incorrect component orientation or placement.

  • Electrostatic discharge (ESD).

Fix:

  • Implement temperature-controlled soldering and rework stations.

  • Add orientation indicators on silkscreen.

  • Ensure ESD protection throughout production line.

💻 6. Programming & Firmware Issues

Symptoms: Board powers on but fails to execute intended functions or connects improperly to external systems.

Root Causes:

  • Incorrect firmware version.

  • Improper flashing process.

  • Memory or communication line issues.

Fix:

  • Integrate boundary scan or JTAG testing early.

  • Validate programming steps with checksum verification.

  • Use shielded lines and impedance-controlled traces for high-speed signals.

📈 How SUNSOAR Ensures PCBA Quality

At SUNSOAR, we integrate multi-stage testing protocols, including AOI, X-ray, ICT, and functional testing to eliminate failures before shipping. Additionally, we maintain close collaboration with our clients during DFM (Design for Manufacturability) and DFT (Design for Testability) reviews—ensuring reliability from prototype to mass production.

Our strength lies in offering:

  • Quick-turn PCBA prototyping and small-batch production

  • High-reliability boards for industrial, medical, and automotive sectors

  • 24/7 engineering support and end-to-end customization

🆚 How We Compare with Competitors

Feature

SUNSOAR

PCBWay

JLCPCB

ALLPCB

Test Coverage

ICT, AOI, X-ray, FCT

AOI, X-ray

AOI

AOI, Basic ICT

DFM/DFT Support

✅ Customized

Partial

Limited

Partial

Small Batch Service

✅ Excellent

Good

Limited

Good

Response Time

⏱ Fast (<12 hrs)

Moderate

Slow for complex

Moderate

Engineering Expertise

🧠 High-touch

Standard

Entry-level

Entry-level

Conclusion

No PCBA production line is immune to defects—but a proactive approach to understanding and addressing common test failures can drastically improve yield, reliability, and customer satisfaction. Whether you're prototyping a new design or scaling to volume production, SUNSOAR is here to support you with technical expertise and quality assurance that stands out.

📩 Contact us today at sales03@sunsoartech.com🌐 Visit www.pcbsun.com📱 Call/WhatsApp: +86 13632793113🎥 Follow our technical tutorials on YouTube

 
 
 

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