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[Walt2]

I never unplug the PC or my power strip so I don't know where Walt2 got that info from. 

I never said you did.  I only asked that question.  Part of helping debug something, is to ask questions that help to eliminate certain possibilities.  My hunch at the time, was that you possible kept your power strip 'on' when you wanted your CM15A to remain active, but without thought turned it 'off' at all other times.

The RTC (Real Time Clock) on a PC is powered from either (1) the motherboard's CMOS battery or (2) the standby power supply (the ATX spec's +5VSB). 
 
If one's battery is dead, then the only choice left is for the RTC to run off the standby power supply.  Of course, if AC is "killed" to the PC, then even the standby power supply is 'off'.   One way to "kill" the AC, and possibly not even realize it, is to turn 'off' the PC"s power strip.

If one's battery is weak, then any kind of really odd things can happen, as the voltage drifts up, down, and around the critical minimum value needed by the RTC.

Now, having said all that, it might be possible that the CM15A has a short against the USB +5v, and that kills the standby power.  I mean, USB's +5v is only about 500mA.  So, a 2 amp draw, would not kill the powered 'on' supply, but might kill the standby supply.  Just a guess, though.

[Walt2]

FYI, I'm a retired IBM engineer and although I may not know something someone else does, I am very computer literate.  Not knowing something is why I came to this forum hoping someone else had this issue and could help diagnose it. 

I am from IBM too.  I was there 15 years before moving on.   There seems to be a lot of us. 

The only way for anything to change the RTC, is for it to have software code which calls the appropriate BIOS commands to change the RTC, or to have software code that writes to the RTC's hardware registers directly.

There is no way that the CM15A could do this.

I also don't see how the AHP software could, since it doesn't seem to have any code or function that can do that.  I mean, there is nothing under "tools", or elsewhere, which has an option to "Set PC clock".  Without such code, there is no way for it to happen even accidentally.

[steven r]

...I kept the USB unplugged from the [CM15A]^* for several days and clock works fine and doesn't require resetting.  A simple restart with it plugged in doesn't effect it but if I shut down the PC with it plugged in it retains the time I shut it down when I turn the computer back on...

^*Quote edited for clarity.

Seems to point to the CM15A playing a role in the problem at least. Still not sure how it could do it unless possibly it's shorting the USB port's 5 volts or something. Again I'm note sure if this could cause that, however. Maybe the computer's CMOS battery is weak as Walt suggested. As it has been mentioned earlier, nothing in the design of the CM15A sends a clock reset signal back to the computer nor does the AHP software poll the CM15A for the purpose of resetting the computer clock.

Am I right to assume that current computer time when the computer is shutdown (even if an incorrect or different time from the CM15A) is retained at the time of rebooting? e.g. If say the CM15A was set at 1:00pm, you exited from AHP, reset the computer to say 1:30pm and rebooted the computer. Would the time still be 1:30pm?

I'd also be curious if after powering down while connected to the CM15A, there was any difference between rebooting with the CM15A connected and rebooting without the CM15A.

Message originally entered before reading page 2 of this topic. Edited to note Walt's suggestion of a weak battery.