I have a "spare" 11/750 supply that I can loan you. Since it is out of a machine, I'd need to get it back eventually. If you can troubleshoot it down to a single board I can loan that as well (to save on shipping) I'd also suggest you measure the resistance between +/-15V and ground on the backplane without any cards plugged in. A bad capacitor or shorted pin could make the supply current limit trip as well.