Gents, there's a lot of speculation but below are a number of facts that I think we should view to discount the "maybes":
1/ the audio stoppage has occurred whether a Mac or Windows PC is connected or not
2/ the audio stoppage has occurred whether PT or Reaper or Wavelab is running on said computer or not
3/ I never use any plugins
4/ 99% of my DM running is at 96K, however the stoppage has occured at 44.1K
5/ 99% of stoppages occur after extended running (6 hrs-ish), however it has occurred once just after boot up of the DM
6/ I never use any groups in the DM
7/ DM Automation is turned off 99% of the time
8/ confirmed that the clock lights are also cycling after the stoppage
Noteworthy items:
a/ I rarely run TMC but it happened to be running during the last stoppage (yesterday - and that was the first stoppage for a couple of months)
b/ I currently have firewire, 2 x analog and surround cards, but the first stoppage occured before I installed the analog and surround cards
c/ I have done a factory reset in the past and have had stoppages since then
d/ my DM has been in the same location since new (i.e. not gigged or transported)
e/ my DM was purchased new and has only been used by me
f/ as Jim noted, Tascam replaced the motherboard under warranty when this occured
g/ I'm estimating the stoppage has occured less than once a month, perhaps once every 2 months, but I have not kept a record of this
h/ The stoppage has never occured twice in a row, or even twice in a week
As Dan suggested, I will remove / reseat my firewire card today to remove that element of doubt.
Based on the above I'm thinking that it's narrowed down to an intermittent motherboard based internal clock issue or a power brownout issue.
fwiw I purchased my DM from a U.S. dealer and had it shipped to Oz (as it was only half the price of purchasing one in Oz). The risk was that the Oz distributor doesn't honour U.S. warranty.
