TENMA 72-1086 User Manual

ATX Computer Power Supply Tester

Overview

Operation

Directions

General Pass/Fail Test

Testing Output Voltages

The Tenma Model 72-1086 ATX Power Supply Tester is designed to provid e fast convenient verification of proper operation of ATX
style computer power supplies. Connecting an ATX 20-pin or 24-pin connector to the MAIN POWER connector of this tester will
provide immediate visual indication of operation of the power supply. An analog voltage meter is also included to verify correct
voltage of all applicable pins on this connector, as well as the peripheral power, floppy drive power, +12V CPU and Serial ATA
power connectors.

Typically, ATX style power supplies are switched on/off from the motherboard. The Tenma ATX Power Supply Tester simulates
this command by pulling PIN-16 low (on the 24-pin connector), and placing an appropriate current load across Pin-4 and Pin-5.
When the tester rocker switch is placed in the ON position, the power supplies cooling fan will engage and the LED indicator,
located in the tester rocker switch, will light. This indicates that the power supply is functioning. In many situations, this level of
pass/fail testing is all that is required.

In circumstances where the supply is operational yet erratic behavior exists, it may be desirable to verify correct voltage at all
pins. The DC panel meter, and 14-position and 15-position rotary switches allow easy veri fication of voltages at each of the M AIN
POWER connections, as well as the SECONDARY power connectors, which are used to power external peripherals such as DVD/CD
ROM, floppy and hard drives and Serial ATA devices.

Many low cost computer power supplies have one internal circuit for each of 3.3V, 5V and 12V voltages. In this case, all outputs
whether on the motherboard, the processor or a peri pheral connector, of the same voltage, are int ernally tied together. In higher
quality supplies, these outputs are independent and isolated from each other. The Tenma #72-1086 ATX Power Supply Tester will
independently verify each of these outputs, as well as –5V and –12V outputs located on some mother board connectors.

• Disconnect the computer power supply from the AC power source

• Disconnect all IDE and other devices that are connected to the computer power supply

• Disconnect the large ATX connector from the motherboard

• Set the rocker switch on the tester to the OFF position

• Connect the large ATX connector, from the power supply, to the tester. This will be either 20 or 24-pin, depending upon the

version of power supply under test

• If testing a 20-pin supply, it must be connected to the far right side of the MAIN POWER connector. In this case, the four pins on
the left side are not used

• Connect the computer power supply to an AC power source

• Set the rocker switch on this tester to the ON position

• If the LED on the rocker switch lights, the power supply is functioning

• The ATX connector must remain inserted into the MAIN POWER connector to allow the tester to keep the computer power supply

in the ON mode

• Ensure that the slide switch, located in the center of the unit, is set to the left “MAIN” position

• Use the 14-position rotary switch labeled “MAIN” to individually test each of the outputs on the ATX connect or. See the TYPICAL

PIN CONFIGURATIONS in the following section for information regarding pin usage

• Each rotary switch position is labeled with the voltage that should be displayed on the panel meter

• If the meter displays the voltage level indicated by the switch, the supply should function properly

• Move the center slide switch to the right “SECONDARY” position

• Insert the small floppy drive connector, larger peripheral connector, square P4 connector and Serial ATA connectors into the

appropriate sockets. Depending upon the supply under test, multiple (or none) of these listed connectors may exist

• Use the 15-position rotary switch labeled “SECONDARY” to individually test each of the outputs on these connectors. Note that
each position on the SECONDARY selector is color coded to match the corresponding supply connector

MAIN POWER Pin Configurations

Note: Connector arrangement as shown facing pins on the tester, not on the power supply.

Newer style 24-PIN MAIN POWER connector

Pin 1 +3.3V
Pin 2 +3.3V
Pin 3 Ground
Pin 4 +5.0V
Pin 5 Ground
Pin 6 +5.0V
Pin 7 Ground
Pin 8 Power status indicator “+” connection (directly feeds LED in tester rocker switch)
Pin 9 +5V Standby Power. This pin is always on, even when power supply switched off
Pin 10 +12V
Pin 11 +12V
Pin 12 +3.3V
Pin 13 +3.3V (plus sense return)
Pin 14 –12V
Pin 15 Ground
Pin 16 Remote power “ON” connection. Pull low (tie to ground) to switch power supply on
Pin 17 Ground
Pin 18 Ground
Pin 19 Ground
Pin 20 –5.0V (Not always used)
Pin 21 +5.0V
Pin 22 +5.0V
Pin 23 +5.0V
Pin 24 Ground

Original style 20-PIN MAIN POWER connector

Pin 1 Ground
Pin 2 +5.0V
Pin 3 Ground
Pin 4 +5.0V
Pin 5 Ground
Pin 6 Power status indicator “+” connection (directly feeds LED in tester rocker switch)
Pin 7 +5V Standby Power. This pin is always on, even when power supply switched off
Pin 8 +12V
Pin 9 +12V
Pin 10 +3.3V (plus sense return)
Pin 11 Ground
Pin 12 Remote power “ON” connection. Pull low (tie to ground) to switch power supply on
Pin 13 Ground
Pin 14 Ground
Pin 15 Ground
Pin 16 –5.0V
Pin 17 +5.0V
Pin 18 +5.0V
Pin 19 +5.0V
Pin 20 Ground