PKT-BUS alarms when trying to add a signal group

[wmainc]

Old Definity 9.5 with the even older cabinet that requires the TN2400 daughter board on the TN2401 Netcon/Pktcon. The DS1 board (TN464F) sees the circuit just fine, but as soon as I add the signal group and assign the port I get a PKT-BUS alarm. The alarm will not clear when the signal group is programmed. As soon as I remove the signal group I can clear the alarm with a few tests.
The installed common control packs are:
01A PROCESSOR TN2404 000003
01A PROCR INTERFACE 1 TN765 000017 u u u u
01A NETCON/PKTINT TN2401 000003 01 02 03 04 u u u u
01A NET/PKT BP CONN TN2400 000001
01A TONE/CLOCK TN768 000008
The upgrade to 9.5 software/hardware from V6 was only done about a year ago and there are no other problems. The interesting thing is we just added a C-LAN/MEDPRO combo and have IP trunk groups running from this location to 3 of their other offices with no problems.
I'm thinking probably something wrong with the TN2401/TN2400, but does anyone have any other ideas?

 

[losfep]

add a tn771dp circuit pack. This will clear the pkt-bus alarm.

 

[wmainc]

Moved the DS1 board down to an open slot in carrier A and the alarm did not occur.
As a side note, I was told the same PKT-BUS alarms occurred when first trying to add the C-LAN and MEDPRO boards in carrier D. They were both moved to other carriers and worked fine there.
Looks like some kind of issue with the D carrier.