M1DBH just died on me?

All,
 
Have been running my M1 Gold for a year now, and at 5am this morning, one of my keypads started beeping, and I got a serial expander error message on the screen.  This particular keypad is on the bus directly, while my other 2 keypads run through the M1DBH (they are the only 2 items on the M1DBH).  The 2 keypads connected through the M1DBH were dark.  I tried to re-enroll the modules, but it didn't reactivate.
 
I power cycled the whole system, and that seemed to do the trick, but am worried that this might happen again.
 
Any thoughts?
 
Thanks
 
Scott

Start out by checking your connections.   Follow the wires.  You didn't say where the serial expander (m1xsp) was in the scheme, but let me guess its just upstream of the DBH.  So the power went out to it and also took out the DBH and keypads. 

Haven't touched the connections since I installed it a year ago, and everything looks good there...  The DBH is directly connected to the bus, with the other end of the bus going to my other expansion modules (RFEG, M1XSP, M1X1N). 

Would buy a bad connection/crimp or XSP going south before I bought a bad DBH.

Trace the 12v supply backwards from the devices that went dark back towards the M1 to find where the supply is lost.
 
Mike.

Only 1 device went dark (M1DBH), and it's connected directly to the bus.  All wires check out ok.  I did a power cycle and the M1DBH is working again, just can't afford to have this happen again, with some travel happening soon and a wife who won't appreciate endless beeping! 

I would re-terminate from end to end. A straight passive device on a printed circuit board vs. field constructed terminations....if you do the math, the issue is statistically going to reside in one location far more than the other.