Tag: quad

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PSi 150 Power Inverter

Front
Front

This is a small 120W power inverter, intended for small loads such as lights, fans, small TVs & laptop computers.

End Cover
End Cover

End cover of the unit, 12v DC input cord at the top, power switch & indicator LEDs at the bottom.

Mains Output
Mains Output

Opposite end of the unit, with the standard 240v AC 50Hz Mains output socket.

Cover Removed
Cover Removed

Cover removed from the top of the unit. Main power transformer is visible in the centre here, MOSFET bank is under the steel clamp on the left, the aluminium case forms the heatsink.

PWM Controllers
PWM Controllers

On the right is a KA3525 switchmode PWM controller & on the left is a LM324N quad Op-Amp IC. The buzzer on the far left is for the low battery warning.

PCB Removed
PCB Removed

PCB removed from the casing, with the MOSFET bank on the right hand side. Two potentiometers in the centre of the board tweak the frequency of the switcher & the output voltage.

 

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Chicom “500W” ATX PSU

Cover Removed
Cover Removed

Here is a cheapo 500W rated ATX PSU that has totally borked itself, probably due to the unit NOT actually being capable of 500W. All 3 of the switching transistors were shorted, causing the ensuing carnage:

AC Input
AC Input

Here is the AC input to the PCB. Note the vapourised element inside the input fuse on the left. There is no PFC/filtering built into this supply, being as cheap as it is links have been installed in place of the RFI chokes.

Input Side
Input Side

Main filter capacitors & bridge rectifier diodes. PCB shows signs of excessive heating.

Filter Caps Removed
Filter Caps Removed

Filter capacitors have been removed from the PCB here, showing some cooked components. Resistor & diode next to the heatsink are the in the biasing network for the main switching transistors.

Heatsinks Removed
Heatsinks Removed

Heatsink has been removed, note the remaining pin from one of the switching transistors still attached to the PCB & not the transistor 🙂

Transformers
Transformers

Output side of the PSU, with heatsink removed. Main transformer on  the right, transformers centre & left are the 5vSB  transformer & feedback transformer.

Output Side
Output Side

Output side of the unit, filter capacitors, choke & rectifier diodes are visible here attached to their heatsink.

Comparator
Comparator

Comparator IC that deals with regulation of the outputs & overvoltage protection.

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