Loud. Louder. Loudest.

When the car radio control no longer regulates the volume - prevent imminent delivery stop.

"She only likes music when it's loud ... "* - Especially when their favorite song is playing, music fans like to turn up the volume on their car radios. However, if the volume control of the device is already defective during production, costly delivery stops or recall actions may become inevitable..

PRoblem statementLouder Yes, Soft No

A renowned manufacturer of car radios and entertainment electronics received an increasing number of complaints during production. The volume controller of a certain type of radio only allowed an increase in volume. The result: an increase in volume, but no decrease in volume.

And this, even though the corresponding controller had been produced and installed without problems for years. It was noticeable, however, that the complaints mainly came from regions with a warm climate and potentially polluted air, so that corrosion caused by harmful gases was considered as a possible cause.

Electronic assemblies Risk of failure Consultancy | © @The Sour Cherry Fotografie - Michaela Curtis
Electronics cleaning Analytics Keyence Microscope | © @The Sour Cherry Fotografie - Michaela Curtis

TroubleshootingHarmful Gas Corrosion as the Cause?

However, things are not always as simple as they seem at first glance. Despite conducting various tests for noxious gases, no corrosion was found on the circuit board.

So, how could the malfunction of the controller be explained? To identify the weak point, a ZESTRON technician examined the rotary switch used in closer detail.

AnalysisMechanical Rotary Switch on the Test Bench

He compared a functional "old" rotary switch with one of the new switches and discovered that the lubricant used in the new models had changed compared to the previous versions. However, this new lubricant was not suitable for the warm ambient conditions in certain regions. Instead, it clumped together relatively quickly at warm temperatures, causing the regulator to malfunction.

SolutionAdapted Lubricant Makes for Quiet Sounds

This not inconsiderable change in the composition of the rotary switch had not been communicated to the customer by the previous supplier, so that there was no possibility of checking the new delivery for functionality.

So there was only one solution: To prevent major production losses and costs, the lubricant had to be actively changed in a timely manner. The new lubricant - suitable for warm ambient conditions - provided the solution to the problem and thus ensured a return to musical enjoyment with quiet tones.

Prostock-studio – stock.adobe.com

whitepaper-collectionQuality Test of the Protective Effect of Grouting Compounds Against Harmful Gas and Moisture

Power electronics harmful gas 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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Surface cleanliness Zestron Meier | © @The Sour Cherry Fotografie - Michaela Curtis
Autor: Dr. Helmut Schweigart

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