Cases

Spectrum analysis of the original PCB revealed a pronounced high-frequency disturbance centred around approximately 3.7 MHz. The unwanted HF component was present in the audio signal path and was sufficiently strong to affect the connected Hypex two-channel Class-D amplifier module. As a result, the amplifier remained electrically active at high frequency even when no intended audio signal was present.

Thermal measurements confirmed the practical consequence of this behaviour. With the system operating at idle, the Hypex module stabilised at approximately 65 °C, which was unusually high for the applied Class-D architecture and cooling arrangement. Under load, the module temperature increased further to approximately 86 °C. The combination of the spectrum and thermal measurements indicated that the excessive heat was not caused solely by normal output-power dissipation, but was directly associated with unwanted HF energy from the original PCB.

These measurements provided a clear direction for the redesign. Rather than treating the elevated amplifier temperature as an isolated cooling problem, the PCB circuitry and layout were reviewed with particular attention to HF behaviour, signal integrity and EMC performance. The objective was to remove the disturbance at its source and prevent unnecessary high-frequency energy from reaching the Hypex modular amplifier stage.

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Before measurement

Verification measurements performed with the revised PCB showed that the previously identified 3.7 MHz HF component was no longer present in the spectrum. The characteristic interference detected during the original measurements had disappeared into the residual measurement floor, confirming that the corrective PCB changes had successfully addressed the underlying HF/EMC behaviour.

The improvement was also clearly visible in the thermal measurements. With the revised PCB installed, the Hypex module stabilised at approximately 32 °C at idle, compared with approximately 65 °C in the original configuration. Under load, the measured temperature reached approximately 73 °C, compared with approximately 86 °C previously. The substantially lower idle temperature was particularly significant because it demonstrated that the amplifier was no longer dissipating unnecessary energy as a result of continuous HF excitation.

The combined EMC and thermal verification therefore confirmed that the PCB revision corrected the root cause rather than merely compensating for its thermal consequences. The amplifier returned to a controlled operating condition, with the measured loaded temperature remaining within the applicable operational limits specified for the Hypex amplifier module. This also restored the intended efficiency advantage of the Hypex CoolClassD™ architecture.

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After verification

Frequency-response measurements performed with the Audio Precision™ test platform were used to verify the accuracy of the implemented RIAA equalisation network across the complete audio bandwidth. After calibration, the measured response remained within ±0.15 dB of the defined RIAA characteristic from 20 Hz to 20 kHz, confirming both the accuracy of the analogue circuitry and the calibration stage effectiveness . 

Measurements were repeated under controlled conditions to verify channel consistency and to confirm that the achieved response was fully reproducible across successive measurement cycles, rather than the result of a single adjustment point. The resulting measurement curves provide a direct comparison between the theoretical RIAA characteristic and the measured behaviour of the complete implemented signal path.

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RIAA response - measured versus reference

Additional Audio Precision™ measurements were used to evaluate noise behaviour, harmonic distortion and available signal headroom. These tests verified the performance of the complete analogue signal path under representative operating conditions and provided insight into both low-level noise performance and behaviour as the output level approached its usable operating limits. 

THD and noise measurements were evaluated together with spectral analysis and level-dependent measurements, allowing distortion products, residual noise and the onset of overload to be examined independently. The results confirmed performance consistent with the intended professional high-end design standard and complemented the frequency-response and calibration measurements used during final verification.

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THD+N versus frequency

The DSP signal chain illustrates processing stages, routing, filtering and control paths implemented within the platform.

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Signal chain comparison

The production JIG flashes firmware and automatically verifies key electrical specifications during assembly and production testing.

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Production test JIG

The system was divided into clearly defined functional zones, allowing controlled routing, monitoring and independent addressing within the Emergency Evacuation and Public Address network.

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System & zone overview

Final commissioning included functional testing, simulated fault conditions and verification of correct system behaviour across the configured zones and control paths.

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Commissioning & fault checks

Each incoming Kinefinity unit is evaluated against the reported fault before any repair action is taken. The diagnostic process begins with visual inspection, verification of power behaviour and reproduction of the reported symptom under controlled operating conditions. Where required, the investigation is extended to individual functional areas such as power distribution, internal interconnections, signal paths, connectors, displays, recording functions and firmware-related behaviour during detailed assessment.

Findings are recorded throughout the diagnostic process so that the original complaint, observed symptoms, measurements and corrective actions remain technically traceable. This structured record helps distinguish isolated component failures from faults caused by mechanical stress, connector degradation, firmware interaction or secondary effects elsewhere in the system. It also provides a clear basis for repair decisions and allows observations to be reviewed.

The resulting diagnostic record supports consistent service quality and makes recurring failure patterns easier to identify across multiple units. This is particularly valuable in professional cinema environments, where equipment reliability and predictable turnaround directly affect production availability. By combining symptom reproduction, targeted testing and documented findings, the service process remains technically controlled while preserving a practical link between field experience, repair decisions and future support.

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Diagnostic record

Release verification is designed to confirm that the repair restores dependable operation, not merely that the original fault has disappeared. Each camera is checked under realistic operating conditions, with attention to mechanical integrity, thermal behaviour, power stability and functions affected by the intervention. The objective is to ensure that the repaired unit can return to professional use with confidence and without introducing new service risks.

Particular attention is given to the durability of the repair itself. Replaced parts, connectors, assemblies and internal routing are checked for secure installation, correct mechanical loading and reliable electrical contact. Where appropriate, extended operation is used to expose intermittent faults or temperature-related behaviour. This helps verify that the repair remains stable beyond an initial power-up test and supports dependable performance during demanding professional production schedules.

For cinematographers, camera equipment is a working tool directly linked to productivity and income. Release verification therefore considers operational reliability as an essential service requirement. Recording, monitoring, media handling, interfaces, controls and relevant firmware functions are checked as a complete system before release. The goal is to reduce avoidable downtime and return equipment that can be trusted when it is needed on set or location.

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Release verification