Test Reuse Surplus PC Power Supplies
I have several PC power supplies as shown above. For the hacker they are a source of high-current D.C current. The 3V, 5V, and 12V outputs often exceed 10 amps.
Also because these were pulled from non-working computers, how do we know they operating correctly?
Better yet, can I control the main power output with an Arduino or Raspberry Pi? Yes I can even power them with the main power turned off.
Above I built this adaptor cable to control the supply and the terminal blocks provide easy electrical connection.
When plugged into a power outlet the 5-volt standby is always on producing 2 amps or more of current. I have an LED connected across 5SB and GND.
When the switch is closed PON (green) is grounded. The PGOOD (normally gray wire but white here) terminal produces an output of 3-volts. (5-volts in an ATX1 supply.) The associated LED will turn on.
My original test used a 24-pin ATX2 connector but it works just as well on the 20-pin ATX1 as shown above.
The differences between the ATX1 and ATX2 is pins 11,12, 23, 24 are missing.
The ATX1 produces -5-volts (white) while the ATX2 does not. Some ATX1s have a brown wire connected to 3.3-volts (orange) while most have this as an internal connection.
An ATX1 requires a 10-Ohm resistor from 5-volts (red) to ground. Without this the 5-volt regulation doesn't work. The ATX2 worked fine without it.
Finally here is the main schematic. Note the use of a switching transistor allows an external microcontroller to turn on/off the high current supply.
The constant +5VSB supplies permanent power for the control circuits.
This is also good for testing these supplies as one of the five turned out defective.
On my computer website:
- Exploring Digital Computer Electronics
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- Salvage, Test 2012 AAEON EMB-B75A Industrial Motherboard
- Hardware Review Connecting PC Parallel Ports
- Main Light Fast Linux Desktops with Openbox, JWM
- Test Reuse Surplus PC Power Supplies
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- Add MPG123 Terminal Music Player to Raspberry Pi, Linux
- Basics of Alsamixer Audio Control for Linux
- Add Solid State Hard Drive to Raspberry Pi
- Beep a PC Speaker Add Beeper to Raspberry Pi
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- Web Master
- Gen. Electronics Homepage
- YouTube Channel
- Current Control Circuits
- Design LM317 Constant Current Circuits
- Constant Current Circuits with the LM334
- Experiments with TL431A Shunt Regulator
- Transistor Circuits
- H-Bridge Motor Control with Power MOSFETs
- Insulated Gate Bipolar Transistor IGBT Circuits
- ULN2003A Darlington Transistor Array with Circuit Examples
- Power Supply Basics
- Basic Power Supply Rectification Tutorial
- Basic Triacs and SCR Projects and Circuits
- Transistor-Zener Diode Regulator Circuits
- Arduino Microcontroller
- Arduino Code Examples
- Rotary Encoder Using Arduino Hardware Interrupts
- Raspberry Pi Single Board Computer
- Raspberry Pi Openbox Linux System
- ADS1115 4-Channel ADC Uses I2C with Raspberry Pi
- +Microchip PIC Controllers
- Microchip PIC12F683 Programming Circuits Tutorial
- Microchip PIC16F628A Assembly
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