PS Magazine - TB 43-PS-627

PS, The Preventative Maintenance Monthly

ISSUE 627

FEBRUARY 2005

PS Magazine - TB 43-PS-627 - Page 23 of 33
Installing Them Right
Don’t try to save money on
batteries; replace all three each
time. Make sure the polarity is
correct as you install each new
battery. It’s important to do it
right the first time, because you
might not have the time to do it a
second time.
Put the housing back into the
DTD with the positive contacts
going in the slot first. The hous-
ing will not fit if you put the non-
contact end in first.
Tighten down the four battery
cover screws, but don’t overtight-
en them. You’ll crack the cover if
you do.
Turn on the DTD to make sure
the batteries are working.
43
Keeping Good Contacts
As you install the battery housing, take a
look at the positive and negative contacts on
the DTD. Are they loose? Any burn marks?
Do the burn marks limit the electrical con-
tact? Good electrical contact is a must.
Unit maintenance can replace both the
negative contact, NSN 5810-01-350-8388,
and the positive contact, NSN 5810-01-350-
8387.
They will use a 1/16-in hex head screw-
driver to remove the screws that hold the con-
tacts. Then they will replace the contacts,
making sure to get them in the right posi-
tions.
They will tighten the screws without over-
tightening or they could crack the case.
One strong word of caution: 40,000 battery
housings were replaced in 2003 because con-
tacts were shorted! Never touch the contacts
with your hand or any other material that may
conduct. The fuse in the battery holder will
blow.
Since the fuse is not replaceable, a new
battery housing will be needed.
First, you will get a low battery indicator message readout: LOW BAT. This mes-
sage will be displayed continuously after a low battery is detected and will give you
enough time, in most cases, to complete your current operation.
Don’t depend entirely on the low battery indicator light, though. Batteries have
been known to creep well below 9 volts without the light coming on. Do your best
to keep track of how long a battery has been in the DTD.
When time has almost run out, the low voltage detector (LVD) will activate,
sounding an alarm. You will have enough time to shut down the DTD in an orderly
and secure manner, but not much more.
To replace batteries,
first remove the battery
cover, NSN 5810-01-
347-9668, by loosening
the four screws.
Carefully insert a flat-
tip screwdriver under the
extension lip and pry up
the battery housing, NSN
Once the battery hous-
ing is disconnected from
the DTD, you’ve got 2
minutes to replace the
batteries and reconnect
the battery housing.
After 2 minutes, data is
lost and the DTD must
be initialized again.
You can figure
on replacing
the BA-5123/U
batteries in a
regularly used
DTD about
every 30 days.
The DTD will
tell you when
your battery
time is up.
Check contacts on DTD
Is polarity right?
Put
contacts
in first
Remove the
four screws
Carefully
remove
housing
With housing
removed, clock
is ticking!
PS 627
FEB 05
42
627.42-43(C)
12/28/04
12:18 PM
Page 1


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