SMPS

[Tech&ME]

I am using a ZEBRONICS Smps 400 watts and it seems that its not working properly. System restarts when the power goes off.

Does someone in this forum also use any ZEBRONICS smps ? and if yes, can he / she tell me the performance of it ?

It will be helpful to me, Please.

[pimpom]

I'm not using a Zebronics PSU but ........

By stating that your system restarts when power goes off, do you mean you're using a UPS but the computer restarts anyway when the mains power fails ?

If this is the case, then it could be your UPS and not the PSU (I'm not saying that it cannot be the SMPS). Some UPS'es can cause this. It also depends on how the power goes off - a sudden failure or a gradual one or some fluctuation before going off. Different UPS'es react differently to different kinds of power failure.

OR, do you mean that you're not using a UPS, but your computer starts by itself when power comes on again after going off ?

If that's the case, then it's likely to be your BIOS setting. There's often a choice of settings to make your computer stay off or to turn on automatically when power comes on again after a failure.

please provide more info as pimpom said.....
coz in ur terms all i can get is that uare having ur system on ups....and the load is not supported by ur ups so when the power gos off it takes some time to react and so ur system restarts....
anyway it 99% of a bad or low rated ups u are using.

[expertno.1]

i am using ZEBRONICS

but it is working fine


how old is it urs ?

[rohanbee]

This is confusing a system will always shut down if power goes.
Unless its a UPS, then you better get it changed as it is obviously faulty, i had a data vision one and it would do that sometimes................

[Tech&ME]

Ya let me be more specific ---

First of all I am using a UPS, Second I bought the 400watts ZABRONICS SMPS just 15 days ago and hence I wanted to know weather it has problems or not.

Actually what happens is, when the power goes off suddenly ( Power CUT ) then the computer restarts. But I have used the Same UPS with another PC which has a lower rating of SMPS -- 300 watts and it works fine with it.

So, what i understood now is

1. That the UPS is not able to supply the desired power supply to the 400 watts SMPS.

OR

2. The 400watts SMPS is not working properly.

Now, please tell me which is correct --- option 1 or 2 above.

[pimpom]

It's not quite as simple as choosing option 1 or 2. First of all, your new SMPS does not draw higher power from the UPS just because it has a higher wattage than the 300W unit. The 400W rating is the maximum that can safely be drawn from it. The actual power drawn depends on your config. The other computer may be drawing less power, not because it uses a 300W PSU, but because of its config.

Which leads to the question : Is the system using the 400W PSU a newly assembled one ? Or have you been using the same computer with another PSU for some time without any problem ?

Please provide as much detail as you can. What type/VA UPS, your config and that of the other computer, history of usage, etc. For example, did you upgrade or add something to your config when you changed the SMPS ?

[rohanbee]

I think the problem must be that the UPS is under-powered. Many of these companies say that they have 400 watts whereas actully you might be getting lesser power. I have almost an identical system as you and have this problem also at times.......

UPS is 600va-- i have asked the company for a slightly higer version.
My power supply is 350watts upgraded from 300 just recently.
im getting my problem inspected on monday. As far as i can see the problem is the ups. Because when i switch on my computer this is the pattern --

cpu and then 17" monitor.........i had my altec's on the ups but that had to be removed as the power definately not enough.

Now when the power comes back up everything gets switched on together so obviously the requirement is more for power as everything switches on immediately so one thing always gets switched off...in my case the monitor..

[Tech&ME]

Originally Posted by rohanbee

cpu and then 17" monitor.........i had my altec's on the ups but that had to be removed as the power definately not enough.

Now when the power comes back up everything gets switched on together so obviously the requirement is more for power as everything switches on immediately so one thing always gets switched off...in my case the monitor..

Originally Posted by pimpom

Please provide as much detail as you can. What type/VA UPS, your config and that of the other computer, history of usage, etc. For example, did you upgrade or add something to your config when you changed the SMPS ?

Ok, Now let me tell you that as rohanbee has already stated, its a UPS problem it seems, like he said his monitor goes off and On again when a power cut happens suddenly. And this is what is exactly happening with my Computer as well.

Now as far as pimpom request goes, let me provide you all with more details.

Note :I will refer my old system ( 300 watts SMPS) as SYS 1.
and my new system (400 watts SMPS) as SYS 2. Herein after.

Ok I have this SYS 1, which has the Gigabyte mobo (P4), Pentium 4 processor 2.4 Ghz, 128 MB RAM, 15" Monitor, Modem, No Graphics Card, One HDD 80 GB, CD-Rom drive, CD-RW Combo drive, Keyboard, Mouse, Altec Lansing Speakers.

I use a UPS 600 VA with this SYS 1 without any problem.

--------

Then I have this SYS 2 Which I bought recently, Which has Intel Original Mobo D915GAV, P4 3 ghz, 512 MB RAM, 15" Monitor, Modem, No Graphics Card, one HDD 80 GB, CD-RW Combo Drive, Altec lancing Audio System 6.1 channels, Keyboard, Mouse ( see my signature for more details)

I use a UPS 600 VA with this SYS 2 with system restarting during a power cut as mentioned above.

Now , let me know your suggestions.

[pimpom]

Your two systems are not particularly power-hungry. Actual consumption is often over-estimated. This is why manufacturers of low quality SMPS'es can often get away with claiming a much higher rating than their SMPS can actually deliver.

Someone thinks he needs a 400W SMPS whereas his config needs only 200 or 250W max. He goes and buys a so-called 400W SMPS which can deliver no more than 250W, but that's enough for his system. So he thinks his config is drawing maybe 350W from the SMPS, and congratulates himself for buying a good SMPS. It happens all the time.

Sorry for rambling on a bit, but I wanted to give some background to power requirements. I estimate that your Sys 1 takes 150-200W depending on what it's doing, and Sys 2 uses perhaps 30-50W more. So even Sys 2 should run comfortably with a 300W PSU that can actually supply 300W.

It's hard to make a conclusive diagnosis from a distance. But I'm inclined to think that the new SMPS may be the culprit. I suggest that you try powering the new Sys 2 with the older 300W SMPS and see if it restarts when you cut mains power.

The 400W rating may be reliable, but a defect or a design flaw may be making it very sensitive to sudden changes in mains power.

I said in my ealier post that the UPS could be the source of the problem (and it's still a possibility), but from the details you supplied, I'm now leaning more towards the SMPS.

[Tech&ME]

Yes Mr. pimpom

What you are inclined to be thinking about the problem is correct. And I also have started to think on the same line now, The SMPS is faulty it seems.

I experimented with the SYS 2 as follows and the results are given below.:



The EXPERIMENT 1 : I used 2 UPS to experiment, let call them UPS 1 and UPS 2 .

What I did was disconneted the Monitor from the UPS 1 and connected it with the other UPS - i.e. UPS 2.

Now the CPU or Cabinet SMPS + Altec Lansing Speaker is still connected with the UPS 1 and
Monitor is connected to UPS 2.

The Results :

There are no problem during power cuts now.

Then I went further and did one more experiment.

The EXPERIMENT 2 : I used the same 2 UPS again. This time I conneted the CPU/ Cabinet SMPS + Altec Lansing Speakers + Printer with UPS 1.

Monitor is connected to UPS 2.

The Results :

When there is sudden power cut the same re-starting problem occured.

Now, can you tell me what is wrong in the system ?