[c-nsp] 1841 dumps to rommon only on power failure

[Vinny Abello]

Got an interesting problem I thought someone else might have 
experienced. I have an 1841 in my home that I've used for a while. 
Recently (probably within the past year) I noticed that when it looses 
power, the next time it powers on it doesn't boot properly and just gets 
dumped to rommon. This problem may have existed far longer as it used to 
be on a UPS, but now is just on a surge protector. I know what everyone 
is going to say, your config registers aren't set properly... Well, yes 
they are. I've verified the config register being 0x2102 a dozen times 
now and even reset it a few times to be sure. The odd thing about this 
is if I simply reboot it again, it starts fine. Even if I power cycle it 
with the rocker switch it boots up fine. I literally cannot reproduce 
the problem by powering it off and back on, yet every time there is a 
power failure, it fails to load IOS and a reboot is the quick fix. This 
kind of stumped me having used Cisco routers and switches of all types 
for many many years now. The only thing I could think of is that somehow 
the lack of power for an extended period is causing it. Could this 
behavior be caused by the battery on the main board being too low of 
voltage? I think it was rated for 3.3 volts and measuring slightly over 
3 volts but my memory may be foggy on that. Any other thoughts (other 
than put it on a UPS like it used to be)? :)

Thanks for any thoughts...

-Vinny