EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: danielrlee on December 30, 2019, 03:44:06 pm
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Hi all
Having been a lurker on EEVblog for many years, I've just registered a user account in order to ask for help with my Korad KA6005P bench supply.
I have owned the above power supply for 13 months and up until now, it has performed flawlessly. Having just gone to use it again for the first time in a week or so, it appears to be having an issue outputting a stable voltage greater than 21V. Below 21V, everything appears to be okay, but with the output set to a higher value, the voltage quickly collapses to 21V where you can hear a relay switch. The voltage returns to the setpoint for the briefest of moments, then the voltage quickly collapses to 21V again and the cycle continues until the output is turned off manually.
https://www.youtube.com/watch?v=Kd0wO475V7k (https://www.youtube.com/watch?v=Kd0wO475V7k)
I do not come from an EE background, but I am confident that I could repair the power supply if I knew what was at fault.
So, does anyone know what might be wrong?
Thanks in advance for any assistance you are able to provide.
Dan
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Having continued my search for information about the above fault, I stumbled across the following post detailing the same problem:
https://www.eevblog.com/forum/repair/korad-ka3005p-power-supply-calibration/msg1129188/#msg1129188 (https://www.eevblog.com/forum/repair/korad-ka3005p-power-supply-calibration/msg1129188/#msg1129188)
Following some pointers from a more experienced member, the fault was identified as a faulty relay K3. I'm not sure what they did to remedy the problem, but the user then posted that their power supply was now working perfectly.
Having just given the K3 relay on my faulty unit a couple of strategically placed 'taps' (always worth a try with electro-mechanical devices), the power supply is now outputting a stable voltage. I don't expect the fix to last, but at least I now know which component is at fault for replacement. If (or when) the problem returns, I will update this thread with my experience in order to help others experiencing the same issue.
Dan