Case Study: Diagnosing a Short Circuit Issue for an Industrial Automation OEM

How PCB Power's root cause analysis cleared a fabrication concern and identified a post-assembly process issue — protecting the customer's production quality going forward.

Customer Snapshot

The Challenge

The customer reported a shorting issue between the 5V and ground pins on their printed circuit board during assembly— a critical fault that, if left unresolved, could damage downstream components and disrupt field operations.

Since this was an order from a long-standing customer, the immediate concern was whether the fault had originated during PCB fabrication — raising questions about process consistency and quality control. The customer needed a clear, evidence-based answer.

Technical Solution

PCB Power's DFM review was conducted thoroughly and the boards were fabricated without error. However, DFM support can only extend as far as the information available — and since PCB Power operates under NDA, the end-use application and post-assembly integration processes are not disclosed by the customer. Risks arising from press-fit insertion, mechanical fastening forces, or application-specific integration steps fall within the customer's engineering scope and are best evaluated by their own team prior to assembly. PCB Power's role in this case was to provide clear, evidence-based analysis — and to help the customer identify where in their own workflow the corrective action was needed.

1. DFM Review & Fabrication Quality Verification: PCB Power initiated the analysis with a thorough DFM (Design for Manufacturability) review and a detailed comparison of the customer's Gerber files against the fabricated boards. This review confirmed that the PCB fabrication was carried out exactly to the provided design files — with no process deviations, dimensional errors, or quality escapes on PCB Power's end. The boards were manufactured to spec.

It is important to note that PCB Power operates under strict NDA with its customers, which means visibility into the end-use application, system integration design, and downstream assembly processes is intentionally limited. DFM support is provided within the scope of the design files shared — and in this case, the files themselves were accurate and complete.

2. Physical Board Analysis: To go beyond data and provide a definitive answer, PCB Power requested the customer ship the affected PCBs for hands-on inspection. Upon receiving the sample boards, the engineering team conducted a detailed physical analysis.

During inspection, a key finding emerged — the boards had undergone a post-assembly process on the customer's side involving press-fit technology for mounting hole screws. When these press-fit components were carefully removed, the short circuit between 5V and ground was no longer present. This indicated that the press-fit insertion process was inducing unintended contact between the outer and inner copper layers of the printed circuit board — a condition that originates entirely in the customer's integration process, not in fabrication.

Testing Performed

Multimeter Continuity Test — used to confirm presence and absence of the short circuit before and after removal of press-fit components, providing clear before/after evidence of the fault source

Results & Impact

Production Cleared & Confidence Restored

With root cause clearly established, both PCB Power and the customer had full clarity on where the fault originated. The PCB fabrication was confirmed accurate and reliable, with DFM conducted to the full extent of the design data available. Armed with PCB Power's analysis, the customer was able to take corrective action on their own assembly floor — specifically reviewing their press-fit insertion process to prevent layer shorting in future printed circuit board assembly runs. The transparency and depth of the analysis not only resolved the immediate concern but reinforced the customer's confidence to continue placing PCB assembly orders with PCB Power.

Key Takeaway

Short circuits in a completed printed circuit board assembly don't always originate in fabrication. Post-assembly processes — such as press-fit component insertion, mechanical fastening, or connector integration — can induce layer-to-layer shorts that may not be visible during standard DFM review, particularly when the end-use application is governed by NDA and full system context is not available to the manufacturer.

This is precisely why customers are encouraged to share as much application context as possible with PCB Power's engineering team — within the boundaries of their NDA — so that potential integration risks can be flagged early, before they reach the assembly floor.

This case also highlights a broader challenge in electronics manufacturing — the risk that comes with multiple vendors handling different stages of production. When fabrication, assembly, and integration are split across separate service providers, accountability gaps emerge, root cause analysis becomes harder, and quality issues can fall between the cracks. Fewer handoffs mean fewer opportunities for things to go wrong.

This is exactly where PCB Power's Turnkey Service makes the difference. With a single, experienced partner managing everything from DFM review and PCB fabrication to assembly and quality inspection, there are no gaps in ownership, no finger-pointing between vendors, and no ambiguity about where a problem originated. End-to-end visibility means end-to-end accountability — and that translates directly into better quality, faster turnaround, and fewer surprises on the production floor.

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