Proper way to test PSU voltages with a multimeter?

[Slaimus]

I took the Radioshack multimeter, set it for 20V DC, and stuck the black probe into the black pin hole on the 4pin molex connector, and the red probe into the 12V pin hole. Well, for some reason all my harddrives spun down! I quickly removed the probe and made sure my drives are okay, which they were. What did I do wrong, and has anyone else has this happen?

 

[Navid]

This suggests that either you connected the meter while it was set to measure current (instead of voltage) or something is wrong with the meter.

Make surer to set the meter to measure DC voltage. Then, try measuring the voltage of a battery. If it works, try it on the Molex connector then.

Edit:
Make sure that the meter leads are connected to the appropriate connectors on the meter (marked for measuring Voltage).

 

[imported_Kensai]

That's an odd reaction..

 

[lenjack]

you may have touched or shorted the connector. For safety and ease of use, place the black lead against the metal case, instead of the black wire.

 

[Dough1397]

shouldnt voltmeters be ocnnected in parallel?

 

[Navid]

Originally posted by: Dough1397
shouldnt voltmeters be ocnnected in parallel?

Yes, it should. And, it will be if connected to an unused Molex connector since all the Molex connectors are in parallel (they all have a 12V rail and ground on them).

 

[Zepper]

Yes, attach the black lead to the chassis instead of a black wire - safer. Then touch the read probe to the various voltage points. Set your meter for a lower scale (like 10) if available for reading anything lower than the 12V to get better resolution. As another mentioned, make sure the red lead is plugged into the appropriate socket for voltage (some meters have a socket for each type of measurement - ohms/volts/amps) also if a probe socket is shared (like ohms/volts), there may be another switch that needs to be set to ohms or volts position. RTFM is also a good idea. If you "lost" yours, RS is usually good about having docs online.

.bh.

.bh.