I have two diodes that I believe to be zeners. The schematic uses that symbol but gives no value. One of them is marked C11 ST while the other one is C7V5 ST. I want to replace them both but would prefer something more than a guess if possible. Testing the C11 with a bench power supply, I get about 11.5volts, the C7V5 measures about 7.5volts. I haven't found listings for those exact part numbers. There will always be accompanying numbers or letters that, I assume, affect their value. I've tried looking at various datasheets, but I'm not sure what data confirms whether the component referred to is what I need. Unfortunately, all I know about the boards is that they ultimately output 8volts and 12.5 volts and they receive input from thermistors attached to the cooing units. Any help would be appreciated.