Cannot power on iMac after power outage

My iMac has recently been protected by a UPS Prolink 700SFC.
When there is a power outage (I live in Indonesia and this happens once every few days) I can close all programs and turn the iMac off. When the power returns I can however not turn the iMac back on. Pushing the power button has no effect at all.
Waiting sometimes helps, plugging into another outlet sometimes helps.
What can be the cause of this problem?
Thanks,
Dirk

koetjing said:

My iMac has recently been protected by a UPS Prolink 700SFC.
When there is a power outage (I live in Indonesia and this happens once every few days) I can close all programs and turn the iMac off. When the power returns I can however not turn the iMac back on. Pushing the power button has no effect at all.
Waiting sometimes helps, plugging into another outlet sometimes helps.
What can be the cause of this problem?

Click to expand...

Hi Dirk - you might want to provide information on your Mac (model/year) and the iOS installed. Is this a 'new' problem or did it occur after such an outage (if so, any lightening involved)? Have you detached the Mac from the UPS and plugged the machine directly into an outlet (or preferably several), and if so, any different behavior?

If the Mac is behaving as described whether plugged into the UPS or just into an outlet, I suspect the On-Off switch or the power supply might have to be considered? Any authorized Apple repair services in your area? Dave

koetjing said:

When the power returns I can however not turn the iMac back on. Pushing the power button has no effect at all.

Click to expand...

This could also be a dead clock-PRAM battery - but I don't have an iMac so don't know for sure!
How To Fix Common Mac Startup Problems [MacRx] | Cult of Mac

You need to tell us the model of iMac.

Which iMac please indeed.

Let me explain:

The G5 power pc iMac has bad capacitors and they blow destroying the computer same thing happens to the core duo iMac.

iMac model information

iMac 21.5 inch
Mid 2011
2.7GHz Intel Core i5
4GB 1333 MHz DDR3

OSX 10.9.4

@RadDave:
I only recently bought the UPS because I thought it was not healthy for the iMac to be stopped each time we have a power outage. The computer however started up normally after an outage before I had the UPS.
Now, with the UPS installed, I encounter the problem.
I plugged in the iMac directly in a wall outlet and it then started normally.
I now am not using the UPS anymore because it creates the problem, although I feel it is a healthier solution to quit all programs before shutting down.
There is no authorized Apple repair center anywhere close.

If it's starting up without the UPS, it sounds like something happened to the UPS when you had the outage. What brand and model is the UPS?

I ask for a reason as my Belkin UPS did that very thing after a power outage. The UPS protected outlets on it had no juice but the NON UPS outlets were alive.

@dtravis7
UPS is a Prolink PRO700SFC.

ouch that answers that pro link ups where trash they blew every time you have a major outage i had to remove a bunch of these suckers out of a computer lab because they all failed i went to a better ups that was recommended vs a cheaper one

@johnodd4;
the strange thing is that the UPS actually is continuing to work perfectly.
It protects the iMac as it is supposed to do.
The problem is the iMac not reacting after it has been shut down in the normal way during a power outage.

If plugging it in directly makes the iMac work, how is it the iMac that is bad?

@dtravis7:
I did not say the iMac is bad.
I am just puzzled by the fact that both devices seem to work perfectly but that after a power outage and a normal shut down of the iMac, it is not possible to start the iMac in the normal way when the power outage is over.

But if you unplug the iMac from the UPS and plug it into the outlet it works? If so that is the same as what happened here with my iMac and Belkin UPS.

When the power came back on, was there any flashing lights or beeping sound on the UPS?

koetjing said:

@RadDave:
I only recently bought the UPS because I thought it was not healthy for the iMac to be stopped each time we have a power outage. The computer however started up normally after an outage before I had the UPS.
Now, with the UPS installed, I encounter the problem.
I plugged in the iMac directly in a wall outlet and it then started normally.
I now am not using the UPS anymore because it creates the problem, although I feel it is a healthier solution to quit all programs before shutting down.

Click to expand...

Hi again & thanks for the additional information - I believe that us posters are all agreeing that your UPS is the problem and not the iMac - you can certainly test the UPS: 1) Test its outlets w/ a device as simple as the one shown below (I have that @ home & also a much fancier one); and 2) If you have access to another computer, plug it into the UPS, pull the wall power & replug, and then see how the computer behaves.

Bottom line is that you likely need a new UPS and in your locale you should definitely have one that is operational - I've been buying APC UPSes for years (probably have about 4 now in the house - also plug them into my electronics), and the less expensive ones are under $100. Good luck - Dave
.

Agreed on APC. The one I had before the belkin always worked and never had that issue. Battery died and the Belkin was cheap so I got it instead of the battery and wish now I had not.