Teledyne 7300A Operating Instructions Manual page 78

5 Maintenance
C. Meter reads Negative
(with zero gas flowing
through analyzer)
D. Meter Up Scale or
Overscale
E. Insufficient Span
Control (with span gas)
F. Noisy or Erratic
Operation
5-8
(a) ZERO control may be
misadjusted.
Adjust control to bring indication
up to zero. (refer to Section 4).
(b) If zero indication unattainable with
ZERO control centered, monitor TP6
on preamp board.
(c) Check that infrared source is
operating. If no light check source
element resistance and connections.
(a) Redo full calibarion.
(b) Check for obstruction in sample
beam path.
(c) Check for excessive moisture in
plumbing and sample chamber. Clean
and replace sample chamber.
(a) Recheck zero for excessive off-
set.
(b) Check modulation factor using
certified span gas.
The most eommon sources of
noises are:
(a) Reduced output of infrared source
(5v, 110 ma each) or replace as
necessary.
Teledyne Analytical Instruments
Model 7300A