Metrohm 794 Basic Titrino - Manual (Page 142)

4.2. Diagnosis
794 Basic Titrino 138
4.2.3 Equipment required:
− voltage calibrator, e.g. 1.773.0010 Metrohm pH Simulator
or 1.767.0010 Calibrated Reference for mV, pH, Ω
µ
S, °C
− highly insulated interconnection cable 6.2108.060
− cable 3.496.5070
− exchange units, if possible with different cylinder volumes (or 3.496.0070 dummy exchange unit)
− stop watch or watch with second hand
− digital or analogue voltmeter (if need be, connect a calibrated recorder)
− 2 connecting cables with 4 mm banana plugs
− test plug 3.496.8510 (necessary only if plug ‘Remote’ should be checked)
− test plug 3.496.8480 (necessary only if plug ‘RS 232’ should be checked)
4.2.4 Diagnosis steps
1 Prepare instruments for diagnostic test
• Power off.
• Disconnect all external connections (cables at rear, except mains cable and key-
board).
• Remove exchange unit.
• Power on and immediately press and hold the <9> key until the power up test pat-
tern disappears.
diagnose press key 0...9
2 Perform display test
• Press <2>.
display test
• Press <Enter>.
Characters for a visual check of the display are generated on the eight lines.
Test sequence:
a) The display is cleared and overwritten from the left to the right with a dot pattern ( ▓ ▓ ▓
▓ ▓ ▓ ▓ ▓ ).
b) The display is cleared and both lines are written into with the letters A, B, C,…Z.
c) The complete character set is shown as a moving display. At the same time with
moving display the LED’s „COND.“, „STATISTICS“ and „SILO“ are swtiches on and off.
• The test sequence can be held and then continued at any time by pressing <5>.
• Block 2 is quit by pressing <Clear>.
diagnose press key 0...9