Roche Diagnostics April 2007
Service manual · Version 2.0 A-27
91xx pH/Electrolyte Analyzers 4 Description of modules
Description of modules
Lamp board
The rear panel and SBC board must be removed to gain access to the lamp board.
Remove one screw and washer which hold the board in place and remove the
electrical connectors to remove this board.
Display board
The rear panel and SBC board must be removed to gain access to the display board.
Remove three screws and 50 degree spacers and unplug the preheater or sample
sensor cable from the front and the ribbon cable to the SBC board to remove the
display board.
Fluidic Module
Standard A
Standard A is drawn to the electrode module by vacuum provided by the peristaltic
pump.
9110 pH Analyzers: When Standard A is to be aspirated into the electrode module, solenoid valve A and R
are opened. Standard A is then drawn from the ISE SnapPak
TM
until Sample Contact
1 detects Standard A bridging the T-piece and Sample Contact 1. At this point,
solenoid valve V is opened and solenoid valve A is closed. The standard is pumped up
the tubing, through the wash portand into the sample needle until Sample Contact 2
detects the standard. The peristaltic pump slows down and the standard moves into
the electrode module until detected by Sample Contact 3 (bridge between sample
preheater tube and reference electrode). Then, the pump stops.
9120, 30, 40, 80, 81 Electrolyte
Analyzers:
When Standard A is to be aspirated into the electrode module, solenoid valve A is
opened and solenoid valves B, V and R are closed. Standard A is then drawn from the
ISE SnapPak
TM
, to the fill port, through the sample needle and is sensed by the
sample sensor. At this point, solenoid valve V is opened and solenoid valve A is closed
as the peristaltic pump continues to pump Standard A into the electrode module. As
the trailing edge of the Standard A sample is sensed by the sample sensor, the
peristaltic pump stops.
During the time Standard A is aspirated into the electrode module, the reference
housing is pressurized due to the peristaltic pump providing pressure to the reference
solution line and solenoid valve R being closed. An amount of reference solution is
forced out through the reference junction to provide contact to the sample.
Standard B
The process for Standard B is identical to that of Standard A with the exception of the
operation of solenoid valve B. This solenoid valve is operated in reverse order of
Standard A aspiration.
Standard C (not on 9110)
The process for Standard C is identical to that of Standard A with the exception of the
operation of solenoid valve C. This solenoid valve is operated in reverse order of
Standard A aspiration.
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