On the rare occasion that a Cosel power supply fails, we often find that a high percentage of faults are due to human error rather than product error. 

We are always happy to help you diagnose the fault with your power supply, however, as a first step,
please follow the procedures shown below.

If you have carried out the checks from our troubleshooting guide and your power supply is still not working correctly, please contact us at techsupport@coseleurope.eu and we will do everything we can to assist you. 



Step 1:  

Download our Troubleshooting Guide.

Step 2:

Check all potential points in our troubleshooting guide. These are the basic checks we recommend before contacting us. 

Step 3:

If after checking our troubleshooting guide your power supply is still not operating correctly, please send us an email to:  rma@coseleurope.eu

What we will need from you:

  • The full Cosel part number. Usually found on the label. 
  • The lot code number. This is also found on the label and will normally be an 8-10 digit number. (For PLA, PJA, KH, KL, KR series, the code will begin with L)
  • An outline of what problem is occuring. 
  • Where you bought the product from.

Step 4:

Please download our RMA Flow Chart to understand the procedures we follow for handling returns. 

What we will do:

  • We will discuss the problem with you and make any necessary suggestions/checks. (Depending on what kind of fault it is)
  • We will check the lot code in our system to determine when the power supply was manufactured and if it's still within warranty. 
  • If the unit is within warranty, we will ask you to return the product directly to our Frankfurt office. 
  • We will then carry out initial tests in our Frankfurt laboratory to confirm the unit is faulty. (Please allow up to 2 weeks)
  • If we confirm that there is a problem with the unit, the faulty unit will be sent to Cosel Japan for further analysis (Please allow up to 3 weeks)
  • We will inform you by email, along with an analysis report, the results of our findings as well as confirm the root cause of the problem. (Product or human error)

What happens if the problem has been caused by human error?

If it is found that the cause of the problem has been due to human error Eg. Incorrect set up, connection, overload etc we will offer you the following:

a) To return the unit to you as it was given to us.

b) Depending on the cause of the problem and which model it is, we may offer to repair the unit and provide a quotation. 

c) Dispose of the faulty unit. 

What happens if the problem is due to a component or manufacturing error?

If it is found that the cause of the problem is due to a component failure or manufacturing error we will either:

a) Repair the unit free of charge and return it to you (depending on the model and nature of error)

b) Replace the unit with a brand new one free of charge. 

Important notes:

  • If you have returned a faulty PCB mount product, and the fault is due to a component or manufacturing error, we will not repair the unit, but replace it and our analysis report will still be provided. 
  • If we repair the unit (due to a manufacturing/component error), we will offer a 3 month warranty on the repaired part of the unit. Any remaining warranty for the rest of the power supply will remain in place. 
  • We DO NOT accept returns on any Cosel product which has mechanical damage. 
  • If the cause of the problem is determined to be human error, all shipping and any necessary repair costs will be charged for. 
  • We will not replace any faulty item until the root cause of the problem has been determined irrespective of whether it may be human or product error. If you require a replacement urgently, please check stock at our global stocking distributors. 

 Still having problems or need some more help? Just contact us and we'll gladly help you.