Chapter 2. Introduction
2.1 Scope
This information applies to 3TB borehole instruments manufactured after 2012 and to some 3TB instruments reconditioned or repaired after that date.
It only applies:
when the 3TB is used with a third-party (non-Güralp) digitiser; or
when the 3TB is operated directly using the buttons on a hand-held controller or break-out box.
Note: This information does not apply to 3TB instruments operated using:
the command-line of a Güralp digitiser;
the web interface of a Güralp acquisition system; or
the controls provided by Güralp's Scream! software.
2.2 Overview
The firmware of the SoH (state-of-health) processor within the 3TB has been updated in order to improve reliability. This has resulted in some minor changes in behaviour with respect to LOCK, UNLOCK and CENTRE operations. These changes are not yet reflected in the manuals.
There is evidence that users who are familiar with the older behaviour are operating the newer instruments in a manner that can result in damage to and failure of the instrument. This, unfortunately, has caused a significant increase in failures, returns and repairs.
This documented is intended to describe in precise terms the new behaviour in order to avoid the problems caused by the change.