Voltage drop..ok? - Overclock.net

pohtangina · 08-05-09

Just bought a used modular PSU /ST70F (happy with my purchase)
was testing it with bypass/paperclip with a multimeter tester.

initial voltage was 12.91v then drops to 11.69v when I attach a fan...
still within spec. Im going to use it for my 2nd rig and was wondering if I should be concerned.

Quote:

Originally Posted by NEWEGG.COM

Model
Brand SILVERSTONE
Model ST70F
Spec
Type ATX12V / EPS12V
Maximum Power 700W
Fans Ultra Silent Running 135mm Fan With 18dBA
PFC Active
Main Connector 20+4Pin
+12V Rails 4
PCI-Express Connector 4 x 6-Pin, 1 x 8-Pin
SATA Power Connector 6
SLI Ready
CrossFire Ready
Modular 100% Modular Cables
Efficiency 80% ~ 87% Efficiency at 20% ~ 100% Loading.
Energy-Efficient 80 PLUS Certified
Over Voltage Protection Yes
Input Voltage 100 - 240 V
Input Frequency Range 47 - 63 Hz
Input Current 12A @ 115V, 6A @ 230V
Output +3.3V@24A,+5V@30A,+12V1@18A,+12V2@18A,
+12V3@18A,+12V4@18A,-12V@0.5A,+5VSB@3.0A

Tator Tot · 08-05-09

Connect your Multi meter first, and then let it level out till it has a constant voltage (mine needs to do this, otherwise it it doesn't read as accurately)

Then report back on what it says.

Either way, your initial readout of the 12v line is over spec. (11.4v - 12.6v) which would have me worried about the condition of your unit.

Though, before you freak out, test it the way I described above, and make sure your paperclip is insulated &/or not touching anything.

shinji2k · 08-06-09

You must meet the minimum load on all three major rails. If you don't, you can't expect voltages to be in spec. If you are at no load or only a fan, some units like your Silverstone do not react well to it. Get a complete system hooked up to it and then test voltages.

pohtangina · 08-06-09

Quote:

Originally Posted by Tator Tot

Connect your Multi meter first, and then let it level out till it has a constant voltage (mine needs to do this, otherwise it it doesn't read as accurately)

Then report back on what it says.

Either way, your initial readout of the 12v line is over spec. (11.4v - 12.6v) which would have me worried about the condition of your unit.

Though, before you freak out, test it the way I described above, and make sure your paperclip is insulated &/or not touching anything.

thanks! My testing was apparently wrong. I did have a bare paperclip but I also had an ANTEC TRIO 550w to test just to compare. THe Antec showed more consistency on 12v.5v.3.3v rails (almost spot on)- >both tested plugged into a power strip on the floor with a multitester + bare paperclip to jump it. I now attached the Silverstone to the chassis/mobo/pc (actually just placed it on top of the pc case) and attached the cables accordingly >>>>now the 12v its reading 12.06-08v from turning it on to typing now> I guess some PSUs dont test correctly with the paperclip method which I just discovered

Quote:

Originally Posted by shinji2k

You must meet the minimum load on all three major rails. If you don't, you can't expect voltages to be in spec. If you are at no load or only a fan, some units like your Silverstone do not react well to it. Get a complete system hooked up to it and then test voltages.

As I mentioned above I attached it to a PC and just discovered this. Good to know. I guess its looking good and thanks for all your help.

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Voltage drop..ok?

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