Hi, I have made a 24 pin cable adapter from a standard ATX PSU to a proprietary hp Z400 motherboard connector (see this thread for more info: Modding a Desktop PSU. Need Smart People's Help ).
I have checked all the voltages on the original hp Z400 PSU and then on my adapter plugged in to a standard ATX PSU. Everything seems to be fine except the PG (power-good signal) pin on the proprietary PSU reads 3.26 V versus 4.12 V on the standard ATX PSU. I haven’t plugged in the adapted standard ATX PSU into the hp motherboard yet. I have just powered on both PSUs and put at least some load on them (one 3.5" HDD and two 120mm fans) in order to check the voltages first.
I don’t think this should be an issue because I have read that “voltage on Power Good must exceed 2.4 volts”. So I guess different PSUs can have different voltage on this pin.
I am just asking more knowledable people here before I plug everything in.
Thank you.
As you expected, according ATX spec, 4.12V should be perfectly fine and more up to spec than 3.26V from the original HP PSU. The timings are more important IMO. If your replacement PSU is ATX certified, I won’t worry about timings either. Everything should just work with respect to “power good” signal.
Furthermore, if your Z400 motherboard accepts 3.26V as TTL logic high, there is zero reason to doubt that 4.12V (above it) won’t be treated as logic high. So even without checking ATX specs, you probably won’t have to worry about the voltage of “Power Good”. Just another assurance by logical reasoning that it’ll be fine.
Thank you! Sorry, I messed up and swapped the labels in the picture. But the info in the text is correct. I am going to try to edit the picture if it is possible. Edit: Fixed.
