Set Top Box Repaired
The complaint of this X.Vision set top box was it can’t boot thus no video and audio from the output port: A/V and HDMI.
I opened the cover and checked on the important voltage test points.
The output of power supply were good : 5V , 12 V. So the focus now was on the mainboard. The first voltage test point that I checked was the Flash IC (W25Q32(SO8)) pin 7,8 and it reads only 2.01 volt. It should be 3.3 volt.
Below are the measurements of the output voltages from the SMD voltage regulator ICs: U1, U3 and U4.
Output of U3 is 5v for mainboard. Output of U4 is 1.8 v for CPU but now it was zero volts. This means the IC have problem and need to replace. I wanted to replace the U4 IC (AB3F1) but I can’t find it in electronic stores so I used a substitute part number SY8009A/SY8009B. You can check out the IC data below:
Therefore, I replaced U4 with SY8009B/2A/6PIN , and VCC output of W25Q32(SO8) became: 3.3 v and the set top box came back to life again.
This article was contributed by M.Reza from Iran.
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