Yeah, the things you explained were bit confusing. It is ok if you have already bought something new or you have repaired the old one itself. But I can tell you some things about it.
PSU should be durable, robust and completely field serviceable. It's steady state output parameters should also be considered while choosing a new one.
Just go through http://www.staticon.ca/category/industrial-dc-power-products
which will help you a lot more in this.