Hey, what’s wrong with my psu?????

[cyber mouse45]

Ok, here’s the problem. I made some 7v and 5v mods to run the fans for the new pc that I’m building, but they don’t work with the Antec psu that I’m going to use. When I made them, I checked them with an Aopen 250w one and they worked fine. I have no idea what’s wrong, but I decided to run a test with my other power supplies and a Delta fan to see if they worked or not. Here’s what I found out:

Dell 200w 5v- slow (good) 7v- faster (good)

Aopen 250w 5v- slow (good) 7v- faster (good)

Deer 300w 5v- slow (good) 7v- a lot faster than the other ones, but not full speed (not so good)

Sparkle 300w 5v- faster than the other ones, but not full speed (not so good) 7v- very slow and psu fan went to about half speed

Antec 400w 5v- slow (good) 7v- cuts the psu off right away, or shorts it. (bad)


So what does this all mean?? Is there something wrong with some of the psu’s, or is there something wrong with my mods?? Please help me. Thanks!!

 

[Diggrr]

Nothing's wrong with either your supply or the mod. Some psu's have more 'short sensing' to them than others do. The psu's you listed as behaving badly are actually behaving well in trying not to allow you to shock yourself.

Hoot and PsycoPhreak answered a similar question here, suggesting the addition of a 4ohm 10watt resister in the +5 power line, this should keep the psu's running, as they won't see the mod as a short anymore.

Have fun, and be safe!

 

[LiGhTBoY]

Hey guys I don't know why my multimeter shows 6.45v in my 7v mod. Any help ?

 

[Diggrr]

Did you try pressing firmly with the MM probes? Clean probes?

Try measuring both of the lines individually like +12 & black and +5 & black...are they where they're supposed to be by themselves?