4)
5)
Low Battery Indicator:
remove the fuse
MAIN
Secure the new batteries in place by re-
connecting the battery retaining plate.
Replace the 640N Igniter Tester front panel
top plate and re-tighten the calibration access
screws, taking care not to pinch any wiring.
The variable potentiometer - trimpot RV3 is
factory adjusted to have the low battery
indicator come on at 4.50 VDC. To make this
adjustment,
from the
fuseholder located next to the power switch on
the 640 main operation top panel. R
f the top panel
has’nt already been lifted off.
, as there is ~14” umbilical
wiring and ribbon cabling that connect the top
panel electronics to circuitry mounted inside the
bottom of the 640 case. Set the top panel on end
resting on the bezel of the 640..
With an adjustable DC power supply, set the
power supply output to be 4.60 VDC. Observe
power supply polarity. Connect the power
supply to the wiring labeled “
” + pos.
and - neg. located in the rear section of the
MAIN PCB. (i.e po power supply output
to the anode side). Adjust trimpot RV3 to have
the low battery indicator just come on (negative
sign on display) with 4.60 VDC applied from
the power supply. An increase in power supply
voltage to 4.62 VDC should have the low
battery indicator go out. The low battery
indicator adjustment should now be complete.
Disconnect the power supply, and return the
fuse to the fuse holder. Replace the 640 top
panel to its original location. Return the
calibration access screws to the perimeter of the
640 main top panel .
emove the
10 calibration access screws located around the
perimeter of the 640 top panel, i
Use caution when lifting the 640 top panel up
by the handles
2.
3.
F-4.
Battery Replacement Instructions
1)
2)
Adjust RV1 for a display indication of
100
0
.00.
Check
the
200
K
Ohm
range
with
the
100
K
Ohm
Standard
Resistor
and the 2 Megohm
The rechargeable NICAD batteries (D cell 5.7
AHr each) used in the 640 series Igniter Tester
are durable and should provide years of trouble-
free operation. Some military maintenance
procedures may require replacement of the
640N NICAD batteries as part of the overall
annual calibration plan, even if the batteries are
working well. As with all batteries,
replacement will eventually be necessary.
Batteries may be ordered from AMPTEC
RESEARCH as stock #05-10117, quantity: (4).
The battery replacement process is :
Remove the calibration access screws (10 of
them) located around the perimeter of the 640N.
lift up the 640 series igniter tester
front panel top plate by the handles (using a
push back tilt up, pull forward and lift up
motion). Note: ~14" of umbilical wire cabling
connects the top plate electronics to the main
PCB on the bottom of the case. Delicately tilt
the 640 series igniter tester top plate so the
bottom portion rests on the bezel ring of the
case. Rest the upper portion of the top plate
against the 640N lid, with the umbilical wiring
intact. This top plate lift and tilt process gives
the technician complete access to the internal
electronics of the 640N.
Locate and unscrew the battery retaining
plate on the bottom of the 640 series igniter
tester (take note of internal #6 star washer).
range
with
1
Megohm
Standard
Resistor.
All
ranges
must
be
within
the
specifications
outlined
in
Chapter
B.
There
are
no
adjustments
necessary
for
the
200
K
Ohm
and
2
Megohm
ranges.
Remove the old batteries and replace.
Carefully
3)
Observe polarity!
Summary of Contents for 640N
Page 19: ......
