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Laser Power Supply Testing

Be safe when performing this project.

SAFETY IS MOST IMPORTANT.  IF YOU DO IT WRONG THEN YOU CAN BE ELECTROCUTED.  THE HIGH VOLTAGE AND POWER COMBINATION CAN BE LETHAL.  FOLLOW THE INSTRUCTIONS BELOW. DO NOT DEVIATE FROM THE INSTRUCTIONS REGARDING SAFETY.

The high voltage laser power supply settings can greatly affect the lifetime of the CO2 glass laser tube.  A setting above 30 mA will, in almost all cases, greatly diminish the operational life (changing an expected life of several years to months).  Even though the laser tubes are ranked in months, such as the 60 watt tubes, I have had customers use them for years before they finally loose power.

More recently, the higher power CO2 glass laser tubes, above 80 watts, and certainly 100, 130, 150, and 180 watts have been more inclined to have shortened lives because the power supply is improperly set.  For example, I had an unscrupulous seller who sold me a 150 watt laser with a power supply set at 34 mA.  My Mahoney laser power probe measured 145 watts.  Then, I contacted the seller because my multimeter read 34 mA.  His engineer said the power supply should be set to 30 mA for full warranty on the tube.  After setting to 30 mA, I measured the laser output power and got 129 watts.  Then, I contacted the company and returned the laser because the seller had actually sold me a 130 watt laser with a 150 watt price tag.

Whatever your reason for checking the power supply current, the steps are provided to demonstrate a safe manner to take a reading then take action to remedy.

Step 1: Do Not Touch the Red Wire.

Picture of Do Not Touch the Red Wire.

 

1. Power off laser machine
2. Wait ten minutes. this is the time for the power supply to drain power from its electrical capacitors.
3. Setup as shown in photos below.  You will need to purchase and use two sets of wires.  We recommend a black wire with aligator clips on each end and a red wire with aligator clips on each end.  These wires should be available at radio shack.

A. See the power supply wire connection.  Do not touch the red wire.  It has extremely high voltage that is lethal.

B.  See the thin wire.  It is colored blue, or black, or green as shown.

Step 2: Insert Meter Wires to Measure Current (mA)

Picture of Insert Meter Wires to Measure Current (mA)

C. See the meter below as an example meter.  Some meters are slightly different, so adjust instructions as needed.  Set meter to read current at mA.  Set meter to read DC current.  Insert red cable of meter into meter connection for current (labeled mA, or micro A, or A).

Step 3: The Meter Reading Should Show the Proper Units (mA) and a Zero Value

Picture of The Meter Reading Should Show the Proper Units (mA) and a Zero Value

Step 4: D. Disconnect Thin Wire (colored Blue or Black or Green) From the Laser.

Picture of D. Disconnect Thin Wire (colored Blue or Black or Green) From the Laser.

Step 5: E. Connect Your Wire to the Laser (aligator Clip Is Useful on Return Wire).

Picture of E. Connect Your Wire to the Laser (aligator Clip Is Useful on Return Wire).

Step 6: F. Connect Your New Wire to Meter Red Wire. Use an Electrical Insulator, Like the Wood Block Shown, to Support the Wire at the Connection.

Picture of F. Connect Your New Wire to Meter Red Wire. Use an Electrical Insulator, Like the Wood Block Shown, to Support the Wire at the Connection.

Step 7: See the Solid Electrical Connection. See Its Location, in the Center of the Wood Insulator Plank.

Picture of See the Solid Electrical Connection. See Its Location, in the Center of the Wood Insulator Plank.

Step 8: G. Connect the Thin Wire From the Power Supply (colored Blue/black/green) to the Black Wire of the Meter Using Your Wire (alligator Clips Are Useful).

Picture of G. Connect the Thin Wire From the Power Supply (colored Blue/black/green) to the Black Wire of the Meter Using Your Wire (alligator Clips Are Useful).

Step 9: More Cable Connections Located in the Center of the Insulating Board

Picture of More Cable Connections Located in the Center of the Insulating Board

Step 10: Confirm Electrical Connections. Take Reading.

Picture of Confirm Electrical Connections. Take Reading.

Check and confirm all connections and review these instructions.  After you confirm that all connections have been completed properly, then power on the laser machine.

Using the touchpad, select Menu and set the laser power to 5% and the time to 3000 ms.  Power on the the laser from the touchpad and read the meter after the number settles.  To confirm that you have no problems, there will be no sparks or electrical arcing.  If sparks or electrical arcing then stop all work, power off the machine.

Tech Bravo

My name is Brian and I am a full time geek! Before being pulled in to a real estate firm as their digital marketing guru I was Operations Manager/Senior Network Engineer/Lead Color Digital Imaging Technician for a medium sized Copier/Printer/IT firm. I have been taking things apart since i was old enough to handle a screwdriver and, over the years, have figured out how to put stuff back together. My toys growing up were oscilloscopes, Z80 based microprocessors, tools, and the like and I am heavily addicted to all things technical. I look forward to bringing hi-tech to you! Feel free to contact me if you wish.

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