Part III | Model 6600 | |
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The reference and measuring signal at the first stage of integration can be observed by placing the scope probe across capacitors C4 and C5 respectively located at PC Board 1 in the detector unit. A dual trace scope is advantageous but not required for this observation.
The test points’ significance is that they reveal proper switch action. The display shows a sawtooth pattern which is a
If one is missing, this means that the switch is not switching.
If the sawtooth shows a broken pattern, this means the switching action is feeble or irregular.
The faulty condition of the switch can usually be corrected by moving the switch up and down or rotating it in its holder.
The magnetic mercury reed switch is activated by the action of a bar magnet and a rotating chopper disc.
An aluminum motor mounting block houses a bar magnet. This bar magnet is positioned in parallel with the mercury chopper switch.
The chopper disc is the green and black disc mounted on the filter wheel shaft next to the motor. The disc is composed of both magnetic and nonmagnetic materials.
As the shaft rotates, the magnetic portion of the disc shorts the magnetic flux as it passes between the magnet and the switch. The nonmagnetic portion of the disc will allow flux lines from the bar magnet to activate the mercury switch.
7.6Sample Cell Maintenance
The Sample Cell needs inspection every 6 weeks. For E.P. systems, open the sample compartment and inspect the cell windows for dirt and oil film. This inspection can be quickly done by removing the external folded optyical path assembly from the main Control/Analysis Unit. Disassemble all, clean and reassemble exactly as before.
CAUTION: wear UV goggles if lamp left on.
Teledyne Analytical Instruments