TSP

In this episode Shahriar repairs an SRS SR650 dual programmable filter. The unit powers on with nearly all the front-panel LEDs illuminated but does not respond to any buttons. Schematic and internal measurements show a lack of activity on any of the main processor pins which is traced to a faulty inverter IC responsible for clock generation. The main SRAM IC is also missing and needs to be replaced.
Additional analysis of the circuits and modifications are also presented. However, the unit develops a new problem due to very high thermal dissipation of the 5V regular and full bridge rectifier. A new rectifier is installed and the faulty 5V regular is also replaced. The QuantAsylum QA403 Audio Analyzer is used to characterized the filter and ensure both the high-pass and low-pass filter sections are functional.

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