So, NGS OPUS is based on NGS CORS. I wrote a short entry [ here ] describing the problem.
I though it would be fun to post some images of really whacked CORS sites:
If you were to decide to replace the batteries in a ProMark 3 (or MobileMapper CX) yourself, a good source of replacement batteries would be:
The part is actually a 220 mF super cap. (That is milli-F, not micro-F!)
They are less than a buck-fifty each.