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1-28 Part III
Part III Model 6600
Teledyne Analytical Instruments
2. When balancing is needed, identify the peaks as outlined under 5.5.4.
3. For example, if the reference peak is the shorter one, stop the filter wheel
with the hand and see if screens are located behind the reference filter.
The reference filter is identified by the letter R scribed on the filter wheel.
4. If screens are found, remove them after taking the filter wheel off the
shaft with the special Allen wrench supplied in the tool kit.
5. After removal of the screens and remounting the filter, mount the filter
wheel back on the shaft. Position it correctly on the shaft by lining up
the two paint marks on shaft and wheel.
6. Turn on the instrument and observe the balance on the oscilloscope.
a. If the reference peak is now too tall, remove the filter wheel and add
a screen of lesser density behind the reference filter. Repeat the
procedure until the peaks are within 2 volts of each other.
b. If the measuring peak is equal to or within 2 volts of the reference
peak, the system is optically balanced and ready for calibration.
c. If the peak is still too short, repeat the procedure, but this time put a
screen behind the measuring filter to shorten its peak.
7. After the peaks are balanced, adjust the gain control until the
tallest of the two peaks is 7 to 8 volts. The peaks should still
be within 2 volts of each other.
8. It is always good practice to operate the analyzer with as
low
a gain as possible. Therefore, with the gain control just barely
off its stop, once again remove or add screens in the light path
to obtain as high a voltage as possible without exceeding 8
volts for the highest peak. Readjust the gain for 7 to 8 volts.
This concludes the balancing procedure and the instrument is
ready for calibration.