[sdiy] DC-DC converter problem

[mark verbos]

Hi there,

Does anyone have experience using DC-DC converters? I have a couple  
Cincon CHB50 converters set up to take a 12 volt DC input and spit out  
+24, +15, +5 and -15. The outputs from the converters are fine, but  
the 12 volts going in is dropping down to 6 volts even with nothing on  
the outputs. The data sheet claims they use 50mA when not loaded. It  
happens the same on all 3 supplies I have here, so it must be  
something I'm doing with the converters. I have the ON/OFF pin  
connected to the +input pin and nothing connected to the trim and  
sense inputs. The case pins are grounded.

suggestions? Thanks for any help.

Mark