It is possible for the user to receive a low battery
indication on a single range only (particularly
the 20 ohm range), while the 620 series igniter
tester remains well within operating limits on
other ranges. Unless the user observes a
continuous low battery indication during
measurement, readings are still valid.
Notice for Cal Lab:
The variable trimpot RV3
is factory adjusted to have the low battery
indicator come on at 4.50 VDC. To make this
adjustment, first
remove the fuse
from the
fuseholder. With an adjustable DC power
supply, set the power supply output to be 4.50
VDC. Be sure to observe power supply polarity.
Connect the power supply to the test points
labeled “
MAIN
” + pos. and - neg. located in
the rear section of the MAIN PCB. (i.e
+
power
supply output to the anode side). Adjust trimpot
RV3 so the low battery indicator just comes on
(negative sign on display). An increase in power
supply voltage to 4.52 VDC should have the low
battery indicator go out. Finally, disconnect the
power supply, and return the fuse to the fuse
holder in the rear panel.
Summary of Contents for 620A 4R
Page 28: ......
