Flickering Lights: Is my Power Supply haunted?

elijahsearle

Distinguished
Jul 6, 2012
54
0
18,630
I am starting my first build and have the cheapest parts already collected. When turning on the system however, my room lights dim for less than a second. I want to know why and if this is a problem.
Here is what i have,
Case: Haf X
PSU: Seagate 750w 80+ Gold
Fans: 3 200mm Blue led Megaflows, 230mm Red led fan, 140mm fan, 7 2000 XSPC Xinruilian fans, 120mm Cougar Vortex PWM
Rad: XSPC RX480 V2
Reservoir: XSPC Single 5.25 Bay Reservoir 1 Blue LED

I have the Swiftech MCP655 pump, but not plugged in/installed.

So, the fans and reservoir LED are plugged into two cables straight into the power supply through a series of 3 pin to molex adapters. Specifically two molex cables to five 3 pin/molex adapters and reservoir led to the first PSU cable and two 4 (3 pin) fan connectors to molex, and one 4 pin to molex on the other PSU cable.

Obviously it's a lot of fans, and more 3 pin to molex adapters than what will be in my final build as my mobo has 5 fan headers.

Are the lights flickering because...
A. The Power Supply gathers all 750w at start up?
B. The amount of adapters are too many on one cable?
C. Problems with my house's wiring?

I think (hope) it's one of the first two, because the light flickers once when everything electronic on my house is on or off, just when turning the PSU on.

Any ideas?
 

elijahsearle

Distinguished
Jul 6, 2012
54
0
18,630
Does the PSU draw all 750w when it first powers on? I mean does it retain the charges and then only uses whatever is necessary and draws more, kind of like a backup to make sure there is a steady stream of energy. Say each of those fans are 1w each, that's only 14w but after the initial draw of 750w it only draws 14w.

If it doesn't do that, then something is wrong. Cause I have my 360, on that outlet (unplugged when turning on PC), and I doubt 14w would do that.
 

InvalidError

Titan
Moderator
Some PSUs have up to 60A instantaneous peak inrush current while primary-side caps are charging up while most are in the 30-45A range which is still enough to cause visible dimming if there is more than a ohm or two total effective impedance between the PSU and power grid.

The flickering can also be caused by weak/floating neutral.

Due to their very short duration, those peaks do not (usually) blow fuses or trip breakers.