Sunday, August 3, 2014

Panasonic RX-5090T power amplifier repair

Panasonic RX-5090T is quiet old combo box from Matsushita Electric and its most notable feature is powerful three band SW tuner. Recently I got some RX-5090T unit and its problem is distorted audio output.

PCB and mechanical component distribution of Panasonic RX-5090T combo box

After careful examination we identify C128 (100µF / 10V) and C224 (3.3µF 25V) as defective components. In this unit, VR103/203 (20KΩ) potentiometer is also defective and because of that we got some random distortions when we try to change the volume of the receiver. To fix this issue we disassemble the potentiometer and clean it using isopropyl-alcohol (this potentiometer is not available in local market and only option is to clean it and use it again). After these two fixes receiver starts to work again.

Mainboard of Panasonic RX-5090T combo box

Schematic diagram of Panasonic RX-5090T is quiet difficult to find in the web and we share copy of it in here.
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