Would upgraded caps keep my PSU in spec?

[dingo99]

I have this Mad Dog (SuperFlower) 350w, and I read it's a decent PSU albeit with mediocre caps. It's been fine so far, but once I added a new video card, the +12V goes out of spec under load - my DMM reads it dropping down to 11.25V.

Would upgrading the caps keep this PSU in spec, or am I just asking too much of it? Primaries are 560uF with no visible branding, and the only 16V cap I saw next to the outputs was a 1000uF PCE-TUR.

[davmax]

Re: Would upgraded caps keep my PSU in spec?

First check the +12V rating of your PS to make sure it can support the new graphics card. If OK replace the output caps. I can see six of them on the right side of top view. The originals show no sign of problem, but depends on brand. What is the brand?

[dingo99]

Re: Would upgraded caps keep my PSU in spec?

The label says the +12V is rated for 20A, which matches the video card mfg's recommendation. All of the caps in there are PCE-TUR, except for the unbranded bulk caps.

[linuxguru]

Re: Would upgraded caps keep my PSU in spec?

That PSU is not capable of 350W - it's probably more like 150-200W, with a max of 6-10 A on the +12v rail.

The quick fixes you can do are to change the secondary rectifier on the +12v rail to at least 20A, and increase the capacitance on the secondary pi-filter for +12v to 2 x 1500uF, 16v. Also change the fan to a ball-bearing fan. You can make it more reliable with these fixes, but there's no way to increase the real power output except by major surgery. If it gets overloaded, it stays overloaded.

[Per Hansson]

Re: Would upgraded caps keep my PSU in spec?

Can you get a picture of the components on the secondary side heatsink?

(that is the DC side, the larger of the two heatsinks)

And yea, the design does look cheap, but atleast there is some input filters installed, actually all components seem to be installed so atleast as far as crap PSU's go it's on the upper end of the food chain

[dingo99]

Re: Would upgraded caps keep my PSU in spec?

Let's see... attached to the secondary heatsink are two SBL3040PT and one F16C020C. Not sure I know what that means, though.

[Per Hansson]

Re: Would upgraded caps keep my PSU in spec?

It means that your +3.3v and +5v have 30aH current each available

And your +12v has only 16aH available

That is of course not counting in any other components which way further reduce the total ampere rating

If this PSU is not powering a computer that draws it's power mainly from +5v then it's no wonder things are not working out for you

Specs for the computer are?

[kc8adu]

Re: Would upgraded caps keep my PSU in spec?

had one of those in a while back that did a nuclear meltdown.board was marked super flower with a butterfly logo.the whole secondary side looked like someone took a blowtorch to it.

[tazwegion]

Re: Would upgraded caps keep my PSU in spec?

What graphics card did you upgrade from ~ to?

[dingo99]

Re: Would upgraded caps keep my PSU in spec?

The PC has a 3.4GHz P4-EE, 1GB RAM, 120GB HD, DVD-RW, floppy, and a couple PCI cards. Old video card was a 6800GT and I moved to a 7950GT. So yeah, the P4 and video card are likely overloading the +12V.

I guess I've been lucky or not using this PSU long enough to run into problems. I think I'll replace it with a Forton AX500-PN - the price is right and the series seems to have a decent reputation.

[PeteS in CA]

Re: Would upgraded caps keep my PSU in spec?

Looks like you have a 16A rectifier for an O/P "rated" for 20A max. - not great. And then the 20A max. may be reduced by the combined power rating for the +3.3V, +5V and +12V. And those heatsinks ... as Clara Peller used to say, "Where's the beef?!" Either that fan is a mini helicopter or you've been fortunate.

[dingo99]

Re: Would upgraded caps keep my PSU in spec?

I suppose that explains the fan setup. In addition to the 80mm at the back, there's a 92mm blowing down on the heatsinks. And when the PC is doing anything moderately demanding, the PSU is often pushing more air than the main system fan.

[Per Hansson]

Re: Would upgraded caps keep my PSU in spec?

dingo99; you have been very lucky that your system has not taken damage from that PSU

Especially considering that you only found one single 1000uF cap on the 12v rail

Be sure to atleast consider buying a even higher end PSU to "spoil" your computer, The Corsair 520w (Seasonic built with a good price) or any of the Seasonic 380w and up PSU's would be a good choice

Your PC probably draws around 100-150w when idle but I think under full load you can probably come close to hitting 300w if you are taxing the system allot

[999999999]

Re: Would upgraded caps keep my PSU in spec?

I have this Mad Dog (SuperFlower) 350w, and I read it's a decent PSU albeit with mediocre caps. It's been fine so far, but once I added a new video card, the +12V goes out of spec under load - my DMM reads it dropping down to 11.25V.

Would upgrading the caps keep this PSU in spec, or am I just asking too much of it? Primaries are 560uF with no visible branding, and the only 16V cap I saw next to the outputs was a 1000uF PCE-TUR.

Good caps can't make up for an insufficient transformer. If you measured 11.8V or higher, with DMM, caps would be a reasonable way to reduce the ripple at that average value, but caps can't increase the insufficent 12V capacity you are seeing.

Better rectifier(s) is ideal, but concerning peak output the rectifier is only a secondary concern, the PSU simply isn't designed capable of the 12V current you need and no caps will change that.

[dingo99]

Re: Would upgraded caps keep my PSU in spec?

Yup, I ended up changing it out for a 500W FSP. I thought about going with Seasonic, but there isn't one that would fit my Dell case without cutting. I upgraded the caps in the Mad Dog and sent it to lab/bench duty - currently serving as life support for a laptop with dead AC adapter.

[gonzo0815]

Re: Would upgraded caps keep my PSU in spec?

Well, the FSP is very good too, but it is lacking may be a little of the efficiency the Seasonic are famous for.
Furthermore, the caps in the new Seasonic (at least the black ones Seasnonic S12 II) are very good brand (Rubycon & UCC) wich isn`t the case in FSP units (and most other PSu`s, even far more expensive ones).
But AFAIK the cpas in the actuall FSP units are probably Capxon brand, which is IMO ok for longterm reliability.