asterisk users - Jan 2007 - S400M (FXS) Modules no longer seen

Hi,

I have a TDM21B (A new TDM20B that just arrived plus a X400M that I 
already had).  This card sometimes works, and sometimes only the FXO 
module is seen.

By "works", I mean all 3 modules have the green lights on the ports on
and when zaptel is loaded the log shows:

    Freshmaker version: 73
    Freshmaker passed register test
    Module 0: Installed -- AUTO FXS/DPO
    Module 1: Installed -- AUTO FXS/DPO
    Module 2: Installed -- AUTO FXO (FCC mode)
    Module 3: Not installed
    Found a Wildcard TDM: Wildcard TDM400P REV I (3 modules)

When things don't work, I either see:

    Indirect Registers failed verification.
    [deleted registers in question]
    Module 0: FAILED FXS (FCC)
    Indirect Registers failed verification.
    [deleted registers in question]
    Module 1: FAILED FXS (FCC)
    Module 2: Installed -- AUTO FXO (FCC mode)
    Module 3: Not installed
    Found a Wildcard TDM: Wildcard TDM400P REV I (1 modules)

Or sometimes, I'd get nothing about FXS modules, and only log messages 
about the FXO working.

I removed the FXO so that I have just what was just shipped to me.  Now 
nothing is recognized.  If I manually insmod zaptel, all I see is:

    Found a Wildcard TDM: Wildcard TDM400P REV I

Any ideas?  Before sending this card back, I'd like to make sure there 
isn't something else basic that I'm not doing.  I did supply power to 
the TDM400P.  That was the first thing I checked.

Thanks,
MikeC