if you wish to discuss this article... Efficient PSUs that don't start

So the whole mess is Intel's fault? Would motherboard manufacturer's ever have implemented the surge-protection if it wasn't for Pres-hott? Hmm..

Very interesting read MikeC.

That doesn't seem quite fair... though it's always fun to signle out a scapegoat.

Is this the reason I have had so many problems with my s12-500 and my a8n-sli premium? It refuses to turn on most times and has to be left unplugged for a while before the psu will turn on. If I can get the system to boot then the voltages are generally fine and the system can remain powered indefinitely. The vast majority of the time it seems to trip when turned on.

The problem didn't occur with my old a7n8x deluxe, although since my first a8n-sli was faulty i'm wondering whether it was damaged trying to get that board to work.

I'm worried because I bought it fom pretty much the only company in the uk to stock it at the time and their rma appears a bit flaky. It's a pity there appears no way of directly dealing with seasonic in the uk unlike with most psu manufacturers.

By the way, i've been reading your website for a few months now and I have to say that you're one of the best hardware websites around.

It's not that difficult to jerry rig a high efficiency power supply into starting without wasting excess power during operation.

Get a 20ohm 10watt resistor and a 10,000uF capacitor. Wire the resistor and capacitor in series. Connect the two remaining free leads to the 12V and GND lines on a spare drive connector. The positive terminal on the capacitor goes to 12V.

This simple circuit will pull 0.6A from the 12V line for a little over a second at startup. After that, its power draw will be near-zero. The added draw at startup should be enough to fool the PSU into running long enough for the rest of the system to wake up and draw enough load to keep the PSU running.

While it may be an easy fix, your ordinary consumer who wouldn't know what a capacitor was if it bit him/her on the behind, shouldn't have to be doing it; the power supply should just workâ„¢. It sounds like Seasonic have implemented exactly the fix you describe to get round the 12V minimum load problem.

It's a pity there appears no way of directly dealing with Seasonic in the uk unlike with most psu manufacturers. [/quote]

Like you, Dodgybob, I have found the lack of a Seasonic presence in the UK frustrating, and it is the more hard to understand when their S12 series has such strong support from reviewers and users. We are just left in the hands of vendors who are not always helpful.

In a reply to my asking when the "sleeved" version of the S12-430 would be available in the UK. Walter Sun (walter@seasonic.com) expressed helplessness in the matter. I twice took up his suggestion that I contact Nanopoint.co.uk as they are the sole importer and distributor of their PSUs in the UK. They just do not answer.

Could email Overclockers.co.uk and ask them if their 430 is sleeved. Not sure if thats any help but I noticed that they had Seasonic PSU's.

Two big thumbs up from Ralfy!

This one is way overdue, glad to see it.

Thanks bsdi for your suggestion but their website shows their stock Seasonic 430w.has a total of only two SATA connections, whereas the sleeved version has two on each of two separate cables.
BTW that is one of my reasons for preferring the sleeved version, so that I can intall a SATA drive in a front bay, as well as two in the hard drive bay. Maybe someone can tell me how to adapt for that purpose another cable on the currently available 430 watt PSU, if that can be done without causing a problem. This is definitely the PSU I want and there is no sign of the newer version arriving in the UK.

As for the importers, nanopoint, they are still showing "4× fully assigned Serial ATA power supply connectors (incl. +3,3V rail)" as a "Special Feature" of the one they stock, though it is clearly not the newer "sleeved" version and in the specification further down the page it is said to have "SATA-Connector: 2".

Unless I misunderstand the situation, they are doing no good for Sea Sonic, their vendors or the retail customers - and deserve a sharp kick.

There are Molex-SATA power cable adaptors available, for example:

Serial ATA SATA Power Converter Adapter -Molex to S-ATA

This would seem to be a good solution if you cannot find the sleeved version in the shops.

Thanks Jaganath for that prompt and helpful reply, especially as I am so far off topic.
I feel a bit stupid not to know these things but the more I delve, the more potential pitfalls for the ignorant I discover. It is good to find there is so much support around.

Although my stuff is much older than what’s mentioned in the article,
it still occurs approximately 1 out of 10 cold starts.

I will try the resistor/cap fix.

Interesting read nevertheless!

I bought a Seasonic S12-430 from scan.co.uk a week or two ago, and it seems to be the new version with sleeved cabling and 4 S-ATA connectors.

However my PC refuses to boot with this power supply and a Foxconn NF4K8AC (NForce4, Skt 939) motherboard. The fans (PSU, CPU, case fan) spin for a second or two, then everything stops.

I can't be sure the issue in this news post is to blame, but my old no-name 350W PSU will boot the system fine.

I'd like to try the suggestion mentioned here to test if this is the problem, but I'm not confident at all working with capacitors or resistors.

You don't have to use a capacitor and a resistor. Just the 20ohm 10W resistor will do fine. Stick one end into a yellow wire pin and the other end into a black wire pin in a spare 4-pin output plug. Make sure those leads don't short. Secure the resistor & insulate the leads with a piece of tape. Then turn the power on. See what happens. If the system turns on & runs w/o problem, you'll find the resistor will get hot.

In any case, you should contact Seasonic with this info and see if they can get you a replacement that will work properly with your system.

It seems that I have this problem with starting my new system. If I unplug hdd it just refuses to turn on. And I wanted to hear the system noise without hdd, since with cpu fan turnd off (only fan in the system) it make some annoying buzz noise which probably comes from hdd.

I also have another strange problem if I put case in horizontal position than it starts most of the time, if I put it in normal vertical position then most of the time it will not start. (I am waiting for Antec P180 and meanwhile I am temporary using some unknown midi case which I leave open).

p.s. Oh yes, I forgot. THANK YOU SilentPCReview for great articles and for helping me to decide which components to buy!

Hello.
It seems that I'm faced to the problem mentionned in Mike's article "Efficient PSUs that don't start" http://www.silentpcreview.com/news652.html

More often that not the PSU starts the system, but sometimes the POST does not occur.

Cf my configuration below.

Is information available now about evolution of this issue ?

~ Can one circumvent this problem in a different way than building an electronic assembly by oneself ?
~ Is it now possible to list the PSU with this problem fixed ?

Regards.

j-p


----------------------
BIOS : Phoenix Award workstation BIOS V6.00 GP
PSU : Fortron Bluestorm 400 W
MB : Foxconn 6150K8MA-8EKRS
AMD 64 3800+
CPU fan : Gigabyte
RAM : Corsair TwinX 3200 C2 1Go X 2
HDD : Raptor 150 Go
CD ROM drive :Samsung IDE.
Case : Pype
W XP SP2

http://www.pype.net
http://www.fsp-group.com.tw/english/1_p ... &proid=127
http://www.foxconnchannel.com/fr-FR/Pro ... -FR0000034
http://www.corsairmemory.com/corsair/pr ... 3200c2.pdf
http://www.westerndigital.com/fr/produc ... riveID=189

Try adding a fan powered directly from the PSU output lines. A typical 0.3A 12v fan will draw 3.6W. This might be enough to stabilize the system. Even if you use a voltage controller to reduce the fan speed, the total power draw will be the same -- in order to slow the fan down, the controller absorbs some of the current. In fact, most controllers will cause total power draw to go up a bit due to losses within it -- so the total power might actually go up a a bit (less than a watt). If one fan does not work, you could try two.

AFAIK, among high efficiency PSUs, all the newer Seasonic models (with sleeving on output cables) now can run with virtually no load. Ditto the Antec NEoHEs (though there's more of chance you will get an older sample -- not good.) The Silverstones seem ok, too. No sure about others, not enough experimentation.

Based on these specification:
http://www.fsp-group.com.tw/europe/1_pr ... &proid=328
it seems that FSP400-60GNF requires more than one fan to start.
It requires 1A, so maybe 3 fans will be enough

Are fans in Antec P180 connected to 12V?

You forget that the system does draw some power -- just not enough. Adding one fan could make it enough. Just try it.

P180 fans run straight off the PSU, yes.

My Antec P180 should arrive this week, so I will wait for fans inside it and then I hope there will be no more problems with PS not starting

Thank you Mike for these advice, and information about the PSU that are ok.
They will be helpful to me.

More information about the dysfunction I am faced to :

 After a failure, if I unplug and plug in again the power cable from the computer, then the system usually starts at the next trial. If I don't do that, the next trials of starting are unsuccessful.
 Sometimes, when the power cable is unplugged, I push the power button one or several times as I see, on some forum, it was useful to do ; when I do that, frequently this makes the lights on, and, at times, the fans too, for a split second.
 After having read your article, I already tried to rise the load by adding too fans (but they are little [40 mm] because designated for HDD location), and a HDD (old Seagate Medalist), without any result, probably because the amount of extra load added is too low.
 In order to maximize the load I put the knob of the PCU fan potentiometer at the maximum position before to try to start (without any effect) ; I understand now that it is hopeless ("Even if you use a voltage controller to reduce the fan speed, the total power draw will be the same ").
 I sent two emails to Fortron company without any answer (If SPCR can support my request it would be great).

More questions, if you don't worry :

 What kind of explanation can one evokes for the help provided by the unplug/replug of the power cable ?
 Is the fact that the dysfunction is inconstant, an argument to think that the electrical set (PSU + mother board + devices) is close to be ok ?
 Has the electrical load to be optimal for every output cables bundle, or has the optimal load, needed for normal starts, to be considered as a whole for the entire PSU ? IE : Can I add the extra load needed to any bundle ?
 I consider to install a graphic card one day (my MB has an integrated graphic controller that is enough for my present use). I hope this will solve the problem if it is persisting, because I believe these devices to draw a lot of power. Am I right ?

j-p

Hello Skromnibog. Our PSU are not far from each other.
I do not see from which information you infer that your PSU requires 1A.
Could you help me please to understand how to deduce such an information from the specifications ?

j-p

There is information minimum load on the link I posted. I suppose that that is minimal current required on +12v1 and +12v2 to start.
However, I am not expert in this field and that is just my guess.

I didn't turn on my computer for 2 days and PS was unpluged. Now I can not start system anymore.
Problem is similar to cavok's.
When I plug in cable, wait for 1-2 mins and try to turn on system I get short rotating of cpu fan (2 sec) and then it stops and power led blinks. After that computer just does not react to the power button. If I unplug cable wait for power led to stop blinking and try again the same thing happens.
Unfortunately I don't have any additional fan or device to try attaching it to the PSU

Questions:
-Did I make mistake because I unplugged PS for long time?
-Is this problem related to Efficient PSUs that don't start or I have defect motherboard or/and PSU?

I succeded starting my system.
What I had to do is to plug CPU fan into system fan connector.
I suppose the problem was in motherboard and not in the PSU.
After starting the computer for the first time, I can now also start it when CPU fan is pluged into CPU fan connector.

There are many easy ways around this problem, if you don't want another fan. You could hook up a small 12v light, mounted internally or externally. Many ways......

cavok --

Some of the questions you ask have to do with the fact that the capacitors in the PSU remain charged up; when you unplug it from the wall, they discharge. In effect, you're completely resetting it.

Also, if one fan does not help, try two or more. But they must be hooked up to the 12V output from the PSu directly, not through the motherboard.

Finally, if you want to verify that your problem is too low a 12V load (or too high a minimum 12V load requirement on the PSU), then you may have to try the 20ohm resistor trick described in other posts above. If this works and makes the system start and run consistently, then you're perfectly justified in returning the PSU for a refund and getting one that will work with your components (mainly, your motherboard).

Finaly my Antec P180 arrived. Now, with all 3 fans connected to Fortron Source FSP400-60GNF, system always starts (even after being unpluged for a long time).
Afterall it seems that problem was just "Efficient PSU that does not start".