Thursday, July 10, 2014

AKAI A1211 DVD PLAYER - SMPS SCHEMATIC and TROUBLESHOOTING (TEA1523) - Power Control IC

SMPS (Power Supply) - Working principles.
  The mains power (220V AC) fed from N1 is filtered through C1, L1, C2 and L2 then rectified by D1, D2, D3 and D4 and generates an output at 00VDC. This 300VDC fed to T1 (pin2, pin4) which connects to TEA1523P (pin2), then TEA1523Pwill automatically generate a 50 KHz square waveform, this 50 KHz square waveform controls the ON/OFF between TEA1523Ppin2 and the ground. In normal condition, T1 primary (between pin2 and pin4) will create a 50KHz square waveform which is controlled by TEA1523P , this signal then fed to T1 and generates 2 different potential voltages of 12V and 5V between pin17, pin14 and pin16, pin14 respectively . The 12VDC and 5VDC then rectified by D7, D8, and D9 and then filtered by L3, L4, L5, C9, C10 and C1 1. The feedback voltage is controlled by Ic3 TL431 and IC2 PC817. When the output voltage is higher than 5V , the voltage at TL431(2.5V) is compared with R10 and send out a signal to 5L0380R, the output square waveform then will change to adjust the output voltage, this acts as a voltage stabilizer.
SMPS PROGRAMMABLE SHUNT REGULATOR.
  The TL431/TL431A are three-terminal adjustable regulator series with a guaranteed thermal stability over applicable temperature ranges. The output voltage may be set to any value between VREF (approximately 2.5 volts) and 36 volts with two external resistors. These devices have a typical dynamic
output impedance of 2.0W  Active output circuitry provides a very sharp turn-on characteristic making these devices excel lent replacement for zener diodes in many applications.
POWER SUPPLY FAULT TRACING FLOW CHART
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