Metrohm 794 Basic Titrino - Manual (Page 141)

4.2. Diagnosis
794 Basic Titrino 137
4.2 Diagnosis
4.2.1 General
The 794 Basic Titrino is a very precise and reliable instrument. Thanks to its rugged con-
struction it is virtually impossible for external mechanical or electrical influences to have
an adverse effect on its functions.
Although the occasional fault in the instrument can not be excluded completely, it is cer-
tainly much more likely that malfunctions are caused by wrong operation or handling or
through improper connections and operation with non-Metrohm instruments.
It is advisable in each case to isolate the fault with the rapid and easy to perform diagnos-
tic tests. The customer thus need not call METROHM service until there is a true fault in
the instrument. In addition, with the aid of the numbering in the diagnostic program he
can provide the service engineer with much more accurate information.
In inquiries always quote the manufacturing (page 4) and program number (see configu-
ration, page 23) and specify possible error displays..
4.2.2 Procedure
• The diagnostic steps must be performed in sequence and compared with the reac-
tions of the 794 Basic Titrino (indented). In the "yes" case, continue with the next in-
struction.
• If the instrument does not show the expected reaction ("no" case), the appropriate
diagnostic step must be repeated to exclude an operating error. With repeated
wrong reactions, however, there is a strong possibility that a malfunction exists.
• The diagnostic steps allow re-entry into the test routine for repetition if the following
display appears:
diagnose press key 0...9
If the instrument is in a subprogram of the diagnostic routine: Press <Clear>.
If need be, switch the power off then on again after a few seconds. At the same time press key
<9> until the above display appears.
• If <Clear> has been pressed during the display of 'diagnose press key 0...9', the in-
strument returns to the user program.
• Error display: An error is shown in the display as follows:
error XX
error number
• If a fault causes the burette drive to stick at the top or bottom end of the cylinder,
see page 148, point 4.4.