Metrohm 797 VA Computrace - Manual (Page 40)

2 Installation
797 VA Computrace / Hardware-Manual 8.797.8001EN
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5 Clean MME
• Clean inner compartments of the MME, contact pin 80 and the screw
threads 76, 78 and 82 with a lint-free cloth.
• If required, rinse all inner compartments of the MME and the unscrewed
individual parts with dist. water and then dry with N
2
.
Do not use any organic solvents.
If you used water to clean the MME, make sure that the inside of the
electrode has dried entirely. Residual moistness can cause problems
during subsequent measurements.
6 Replace sealing needle 75 if needed
If problems with leaks arise owing to a worn, deformed or damaged sealing
needle this must be replaced. Three spare needles are supplied separately in a
protective plastic package. After unpacking a needle, please avoid any contact
whatsoever with the needle tip. The spare needle 75 is installed as follows:
• Carefully pull old sealing needle out of PTFE membrane of the slotted screw
74.
• Carefully insert new sealing needle without tilting into the hole in the PTFE
membrane of the slotted screw.
When the sealing needle 75 is changed, it is always necessary to
change the glass capillary 87!
7 Replace sealing ring 84 if needed
• If the sealing ring 84 is contaminated or damaged in any way, it must be
replaced for the subsequent assembly of the MME. Two new sealing rings
are enclosed in the package with the 6.1226.030 (normal) resp. 6.1226.050
(silanised) glass capillaries.
8 Reassemble MME
• Screw slotted screw 79 using a suitable coin flush into screw thread 78.
Do not turn so tightly that the cemented-in steel threaded ring 78
becomes loose and hence jeopardizes the tightness and safety of the
MME!