UPS Problems

I have a Dell Studio XPS 9000 with a Inter(R) Core (TM) i7 CPU @2.67GHz. 8.00GB RAM 64-bit Operating System and a NVIDIA GeForece GTS 240 graphic card. The problem is when it running on a UPS in battery mode the computer starts and restarts. I have try 3 other UPS'S the work on my two other computers. The XPS 9000 only draws 1.2 amp at the highest most of time it using .8 amps. Could it have something to do with frequency not being a true sin wave. And Help would be great

 

The power supply in your computer seems to be suspect. Short of swapping it for another unit to test, I don't see any way out.

 

NO!!!! I say that emphatically because this "you gotta have true-sine wave" BS is just that - BS! It is marketing hype by the makers of true sine wave UPS makers. Nothing more. For decades "step approximation" UPSs have been used without problems on countless mission critical systems for the military, medical, communications, data centers and more. The ONLY reason we are hearing more and more about true sine wave UPS is simply because their costs have [finally] come down to be competitive with traditional UPS.

And BTW, it is not the frequency, but voltage sine wave. The frequency will be 50 or 60 Hz, regardless (depending on where you live).

The only systems that might actually need true sine wave UPSs are critical health monitoring and life support systems in intensive care units or active operating rooms.

Note too that modern computer power supplies are much more fault tolerant than power supplies of old. So today's power supplies are even more capable of dealing with the minor waveform anomalies (if you can even call them that) of a step approximation waveform output of a UPS.

I agree with rsinfo - you need to swap in another known good PSU and see what happens.

You should also make sure you facility wiring is good.

Every home and every computer user should have access to a AC Outlet Tester to ensure your outlet is properly wired and grounded. I recommend one with a GFCI (ground fault circuit interrupt) indicator as it can be used to test bathroom and kitchen outlets too. These testers can be found for your type and voltage outlet, foreign or domestic, (like this one for the UK) at most home improvement stores, or even the electrical department at Wal-Mart. Use it to test all the outlets in the house and if a fault is shown, have it fixed by a qualified electrician.

Lastly, make sure you are not powering the UPS through a surge and spike protector (S&SP). The UPS monitoring circuits can see the waveform from the S&SP as "dirty" and sporadically flip back and forth between line and battery. And do not connect a surge and spike protector to the output side of the UPS as the UPS may see the load as bad.

 

I don't think it is the power supply because i check the current draw when the computer running and its only 1.2 amp at peak most of the time it's .8 amps.

 

The only thing have not checked is the AC Outlet. I know must home UPS are step sin wave not true RMS but why just a Dell Studio 9000. the GFCI Light in not lit on the UPS but i will check out the AC outlet with a meter and plug the UPS in to another plug and see what happens.
I will post what i find

 

That means nothing except you are pulling from the wall less than 140W most of the time.

Are the +12V, +5V and +3.3V outputs all within the maximum allowed ±5% tolerances? Across all expected loads? Is the maximum ripple well below the maximum 50µVpp allowed? Unless you are a qualified electronics technician with the proper test equipment (oscope and power supply analyzer) and you know how to use them properly and correctly interpret their results, you don't know if your supply is providing good, clean, stable, within specs power. And since EVERYTHING inside your computer case depends on good, clean, stable power, the only way to eliminate your PSU from the equation is to swap in a known good spare.

My guess would be because of its power supply!

 

I am a qualified electronics technician but am i retired. I lack a o scope and power supply analyzer but have meter and voltages are OK. The computer is clean and every thing works OK until i unplug the UPS from the AC outlet. i don't a a spare power supply to swap. the AC outlet check OK also. i may just have to live with it

 

As seen via the link in my sig, I too am a qualified technician. As you know, most multimeters cannot measure ripple. And testing voltages with a meter is not conclusive unless you test the supply's output with the supply under a wide variety of expected and proper loads. This is generally from just 10% load up to full 100% loads.

How old are the UPS batteries? Note that typical SLA (sealed lead-acid) batteries need to be replaced every 3 - 5 years. Fortunately, with most UPSs this is a fairly easy task.

Scratch that - I just re-read your opening post and you said this happens with 3 different UPSs so not likely due to faulty batteries.

No, you need find a spare, or just buy a new PSU. Sudden shutsdowns or reboots can put undue stress on the connected devices and more likely corrupt your hard drives resulting in an unbootable operating system and worse, data loss.

I like to say you don't spend good money on a BMW then fill it up at the corner Tobacco and Bait Shop. At least with a car engine, it can miss a beat and keep running, but not so with digital electronics. So I would urge you to bite the bullet and "invest" in a quality 80 PLUS certified PSU, preferably one that is at least certified Bronze. I prefer EVGA supplies, but Seasonic, XFX, and Corsairs are all good as long as you stay away from the entry level lines.

 

Or if the computer is under warranty, just call Dell.

 

Good point.

 

computer no under warranty

 

Then either you swap power supply or live with it.

 

I would love solve the problem just to find out what it is. if it is the power supply like to know what wrong with it?

 

If you renew your PSU and the problem is fixed, then you would need to assess whether your time is worth it to dismantle the old PSU and test the components. Usually heat will be the destroyer of PSU's or cheap componentry. Your choice.

 

I second retiredlearner. Weigh the time & labor element carefully before doing anything.

 

I still can't how the PS can work just great on the UPS when i is plug into the AC outlet and cycle on/off when on UPS battery. But has to be the computer the problem flows the computer

 

Since you tried this with different computers and 3 different UPS, once again, it points to your power supply. Swap power supplies (perhaps with one of your other computers), or as suggested above, live with it.