I have a GW INSTEK Mains Adapter GPR-0830HD (power supply). When the unit is powered on (110vac, US) the unit jumps to full voltage (~15vdc), with no response from current or voltage limit controls. And when shorting positive and negative leads (as would be done to adjust current limits prior to normal use) both voltage and current drop to zero, again with no response from the controls. The unit (which was found in storage) is essential new with no visual signs of corrosion or burn marks.
I have not worked on power supplies in >30 years so please forgive me if there is an obvious place to start. Might you have any thoughts as to what is wrong or where to start? Also, I could not find any schematic for the unit, only user manual.
Thanks in advance.