OMNI-IIe freezes within 24 hours of re-start

We have had an OMNI-IIe for several years.  A few months ago it started to freeze up, required power cycle to restore:

• no network access with PC-Access
• no nework access with Snap-Link
• Console diplays "No Controller Data"

So yesterday I replaced the Controller with a brand-new controller, updated the firmware to V3.16 released in July 2016 and loaded my program file.   Everything works.
 
But then this morning the new controller was off-line:

• no network access with PC-Access
• same as above
• same as above

What can Cause this ?

• I am using the original ELK 24 volt AC power supply.  It measures 27 volts AC at the controller.
• Can a user's program error cause this ?
• Can the firmware be bad ? both controllers had V3.16 - the newest available

When the original controller froze, it was really messed up, nothing worked and the console display was scramble after a reboot until I reloaded the program file and maybe updated the firmware at the same time.  I thought maybe it was related to a lighting storm.  I was confident a new controller would fix this.

Yes, user programming can cause this problem.  If there are loops or things that execute too frequently, you can see this.  I would start by saving your config file under a new copy and delete all the programming, then download to the panel.  Let it run for a while to see if the problem exists.

Do you recall making any changes back when the problem first started?

I have taken your suggestion of loading a copy of the .pca file with all programs deleted.
 
Since both the old and new controllers freeze, I am also wondering if their is some wired connection that has some stray voltage or leakage to ground that has occurred.   If needed maybe Ill start disconnecting these systems one at a time.

• security zone devices 
• Thermostats
• Temp Sensors
• Ethernet - but all other local network systems work correctly
• outputs to horns/speakers
• Leakage to 120v line through the HAI and X10 power line interfaces

 
I don't recall if I made adjustments just prior to the problem originally starting.
 
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I didn't want to confuse the question when I first posted this, but all HAI keypads stopped working about a year ago, plus about 1/2 of the HAI switches stopped being controlled by the controller.  

• I have an HAI brand phase coupler.
• putting the HAI Power Line interface on the other phase changes the response of a couple of the switches but not the keypads.
• Upstart doesn't detect any noise, but it also doesn't seem to find the HAI devices.
    I have 2 HAI power line interface devices and they both provide the same partial functionality.
   

Do you see any potential connection between the HAI communication problem and the Controller-Freeze problem (with both controllers)

I would try unhooking the consoles from the controller. When I reversed the power, fried two consoles, and then connected them correctly the OmniPro would hang / act weird. It appears that the consoles were sending garbled data over the data bus. Once I disconnected the two bad consoles my last console and controller worked fine.

You likely have a programming loop.  These can be tricky to solve, but you need to map out your code to verify that you don't have something like a changes b, b changes c, then c changes a.