Datasheet for the TSOP12XX series of infrared receiver modules, 108 KB PDF. These modules integrate a photodiode, preamplifier and demodulator, and the last digits of the part number usually indicate the carrier frequency, such as 36 or 38 kHz. Repairers use the document to confirm pin order, supply voltage and the recommended RC filter on the power pin. When a remote control stops working, verify supply voltage and look for the output pulsing on a scope while pressing a button, and make sure any replacement matches the carrier frequency.
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