Teledyne 514 Instruction Manual page 53

1. Adjust the input square wave at pin 8 to be equal above and
below ground. To accomplish this R2 must be raised or lowered
in value. This is necessary for proper operation of the rest of the
switching circuit.
2. Check the following test points for proper wave forms (refer to
Table IV at the end of the chapter):
a. TP4 (S). Square wave clamped to ground with +5V P-P.
b. TP3 (S). Square wave clamped to ground with +5V P-P
180° out of phase with S.
c. TP1 (P). Five (5) volt spikes with the tips at ground and
the base line of +5V (5V P-P).
d. TP2 (P). Same as TP1 (P) except 180° out of phase.
e. TP5. Clamp reset pulse. 30V P-P spike centered around
ground +15V and -15V.
f. Remove the card extender and re-insert the switch driver
card in the analyzer.
Balancing the Measuring and Reference Peak
Heights
For the electronic checkout the peak heights are balanced with air in the
sample cell. The peak heights will later be re-balanced with sample in the
sample cell, prior to chemical calibration. The peaks must be balanced within
+10% in air before the electronic calibration can be accurately completed.
1. Connect an oscilloscope to pin 6 on the circuit board connector
of the switch driver PCB. The video from the pre-amp will
displayed on the oscilloscope.
2. To determine which peak is the measuring or reference, connect
another oscilloscope lead (use a dual trace scope) to TP3 on the
switch drive PCB. The +5 volt (positive going) portion of the
square wave will correspond to the measuring peak (see Table
IV).
3. Screen the larger peak until about a +10% balance is achieved.
Never screen both filters.
Automatic Gain Control (AGC) PCB
See dwg. B-14564. Insert the AGC in the detector module. Refer to
Table IV for wave forms and test points (TPs).
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
Maintenance & Troubleshooting 5.0
5–15