How hard is it to upgrade the DAS firmware/software in the field?
New EPROMS must be installed in the CPU board, and possibly the DSP board. The DAS must be opened, the card cage removed, the particular card removed and two chips pried out and replaced with new ones and the whole thing put back together again. An experienced technician can do this in a lab in 40 minutes with about 95% of the DAS working on powerup. In the bush, the rate could drop to 85% and take a little longer. A novice would take twice as long and the odds of it working are lower still. Further consideration should also be given to the dismantling of the station just to get the DAS free from all the interconnecting cables and correctly reconnecting them. As a rule, PASSCAL does not upgrade DAS software during an experiment but has been forced to when bugs have appeared after equipment was shipped. The next best option is to return units to a suitable environment such as the field headquarters and upgrade several units as a group. This allows a certain amount of cross-checking and
