I’ve just discovered an undocumented command of the Velleman PS3005D programmable lab power supply. This PSU is available as a number of clones like Korad KA3005P reviewed at EEVBlog. I don’t know much about the serial communication protocol in the other PSU variants, perhaps they are different.Anyway, in case of the Velleman unit, the over-voltage and over-current protection commands are not documented and not controlled by their own PC software. I have guessed that these commands can be used to turn the features on and off:
I have not found a possibility to read the current status yet, please let me know if you succeed.
I have compared the PCBs in my PSU (purchased May 2013) with the new revision tested on EEVBlog. It seems to be fully updated.
I replaced the stock fan with another 80mm PC fan and the horrible rattling noise is gone. I should take the PSU apart once again and improve the fan control as it is kept on high RPM without load.