HAI Omnipro II Omnitouch screens keeps shutting down

I have three Omnitouch screens in my house, and they are all shutting down (black screen and non-responsive to touch).  After little while, the three screens have an alarm sound, but the screens are still unresponsive to touch. I cycle the power to the Omnipro II system, reset the time and date on the screen, and after about an hour or so, all three screens black-out again. 
 
Also, all the smoke alarms through out the house is making this quiet buzzing/rattling/gurgling sound.  However, all the programs (night lights turning on/off) are working.
 
Any input on what I should check would be greatly appreciated.

This problem isn't caused by OmniPro. I have problem with lot OmniTouch 7 like yours. All Touchscreen need return for warranty

Can you clarify which kind of Omnitouch screens you have?  Are they the ethernet powered kind, or the 12 volt power bus kind?  Do they all go dark at the same time?
 
You may have a power hub going bad, which would explain the touch screens and the smoke detectors all doing strange things.

   
 
Here is the image of the back of the screen.  it's the 12V type. I have 3 in the house, and they all go dark at the same time.    How can I test out to see if it is the power hub? Thanks

This is diagram connect to controller directly:
 
[sharedmedia=gallery:images:1141]

Looks to me that you are drawing too much power from your panel.  Do an audit (bean counting) of everything you have connected to the panel first.
 
Then purchase an aux power supply with battery.  Here utilize the combo HAI touch / CCTV hub sub panel with a battery. 

The setup has not changed in years.  Nothing was added to the system, so if it is drawing more power, I think one of the load may faulty.  I unhooked two of the three omnitouch screens, and it seems ok so far.  I'll keep this setup for few more days (assuming it stays on), and then add the second omnitouch screen to the load.  I'll keep you posted.

Good news that it is working with 2 touchscreens.  How are smoke detectors behaving now?
 
Yes you could have a faulty load or even main transformer starting to go.
 
Many years ago here swapped out the HAI transformer for the ELK transformer.  Thinking because it had a 3rd ground post on it? 
 
I have also seen a near or close to bulging capactor near the power wires on the motherboard. 

A few years back here wires mounted in door frame stretched due to settling of the home and caused intermittent issues.

Thanks Pete_c for your input.  I'll check the components to see if there are any visible signs of defects. 
 
The smoke detectors are quiet.  Maybe I'll blow cigar smoke around it to make sure it is working.
 
To correct your comment, I currently only have 1 touchscreens on.  Planning on leaving it like this for few days, maybe a week, and if I don't see any problem, I'll hook up the 2nd touchscreen. 

So it's been few months since I checked in, but here is what I've done during that time.  I've connected and tested one touchscreen at a time.  Left it connected for couple weeks at a time to see if it's any particular touchscreen.  Then I connected and tested two touchscreens at a time for couple weeks.  With all the testing I've done, the touchscreens have not shut down.  Now I connected all three screens back, and it's been few weeks, and everything seems to be working.  So I'm not sure what the problem is/was.  I guess I'll consider this issue closed until I have the screens shutting down again.

Good news G13392.