InsightsAvoid Recalls: When Volume Controls Fail
How unnoticed supplier changes can cause costly recalls in car radios.
Failure analysis Defective Volume Controls Pose Production Risk for Car Radio Manufacturers
“She only likes music when it’s loud …”
Music lovers often turn the car radio all the way up, especially when their favorite songs play. But if the volume control is already faulty during production, it can not only dampen the joy of listening but also lead to significant production issues. For manufacturers, this can mean potentially costly delivery halts and recalls that may shake the entire supply chain.
PRoblem statementLouder, Yes,
Quieter, No
A well-known manufacturer of car radios and consumer electronics is facing a growing number of complaints. The reason: a specific radio model's volume control is failing. While the volume can be increased without any issues, turning it down is no longer possible.
This defect occurs suddenly, despite the fact that the volume control has been produced and installed without problems for years. Notably, the complaints are primarily coming from regions with warm climates and polluted air, suggesting harmful gas corrosion as a possible cause.
TroubleshootingHarmful Gas Corrosion as the Cause?
Initially, suspicion fell on harmful gas corrosion as the trigger for the volume control malfunction. This type of corrosion occurs when electronic components are attacked by harmful gases present in the air. However, a detailed analysis involving various harmful gas tests did not confirm this assumption.
To identify the actual cause, the investigation continued. A ZESTRON Technology Analyst then examined the rotary switches used in the radios to gain deeper insights into the potential triggers of the defect.
AnalysisMechanical Rotary Switch Under Scrutiny
In the next phase of the investigation, both an "old" functioning rotary switch and a sample from the new series were examined. It was revealed that the lubricant in the new model had been changed. However, this new lubricant was not suitable for the demanding environmental conditions in warm regions. Instead, it aged quickly and clumped under high temperatures, ultimately causing the malfunction of the volume control.
Solution approachAdjusted Lubricant Ensures Smooth Volume Control
This analysis result was crucial, but another issue came to light: The change in the lubricant composition had not been communicated to the customer by the supplier, which prevented an early functionality check of the new components.
To avoid major production outages and costs, the lubricant had to be quickly switched to a more aging-resistant variant. This proactive adjustment ensured that the volume controls functioned reliably again, maintaining the listening experience even at lower volumes.
Failure analysisWhat Challenge Can We Help You With?
Whitepaper CollectionQuality Test for Susceptibility of Encapsulated Power Electronics to Harmful Gas Corrosion and Humidity
Weaknesses in potting compounds of electronic components and assembled PCBs can lead to a significant reduction in service life or even immediate early failure of the entire circuit under unfavorable environmental conditions.
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