HP 5300A - Page 50

left. drift indicates the counter oscillator frequency is
higher than the standard frequency. A right drift
indicates the counter oscillator frequency is lower
than the standard frequency. The rate of movement is
related to the frequency difference between the
5300A oscillator and the standard frequency as shown
in the following example.
Example. A 5 MHz frequency is used to trigger
the oscilloscope sweep; the oscilloscope vertical
amplifier signal is the 5300A oscillator frequency.
The time required for the pattern to drift the
width of one cycle for the display is (in this ex-
ample) 10 seconds. The frequency error is:
Af _ At_ 2x 10-7
f
t
1x10
=
2x
10-8
=
2
parts
in
108
error.
f. Longer measurement periods are required to
observe smaller frequency differences.
g. If frequency difference (drift) is excessive
adjust 5300A rear-panel OSC ADJ.
5-61. HP 5310A BATTERY PACK
5-62. Battery Capacity Check
CAUTION
Maximum recharge time is 24 hours. Bat-
teries may be damaged by heat if limit is
exceeded.
5-63. The condition of the batteries in Model 5310A
Battery Pack can be checked using equipment listed
in Table 5-1 as follows:
a. Mate the 53810A Battery Pack to the 5300A
Measuring System mainframe and the plug-on in use
using procedure in Paragraphs 2-15, 2-16, and 2-17.
b. Unplug the 5300A ac line cord and set 5310A
switch to BATTERY so that the battery pack is oper-
ating with normal load and supplying power to the
Measuring System/Plug-on combination.
c. If the LOW BATTERY lamp starts to glow or
if short battery life has been experienced, the Battery
Pack should be recharged as follows:
1. Connect ac line power to 5300A. (Note: it is
not necessary to have plug-on connected to
charge batteries.
2. Set panel switch to CHARGE for 18 hours.
3. After 18 hours, disconnect ac power and set
panel switch to LINE.
d. Ensure that the panel switch is set to LINE,
then separate the Battery Pack from the 5300A and
plug-on combination.
Model 5300A
Maintenance
e. Connect a load across Battery Pack as follows:
1. Remove the Battery Pack top cover by re-
moving the six attaching screws.
2. Obtain a 10-ohm, 25 W resistor and a 50-pin,
female connector, HP Part No. 1251-0101
(CINCH 57-20500-375). *
3. Solder the resistor between pins 25 and 49 of
this connector.
4. Connect the loaded female connector to the
Battery Pack bottom connector, AlJ1.
f. Set Battery Pack switch to BATTERY.
g. Check the voltage conditions of each of the
five batteries with a dc voltmeter. The normal volt-
age for each battery should be greater than 2 voits
(about 2.3 to 2.8 V depending on time since charge)
and each battery should be nearly the same level. A
difference in voltage level between batteries is an
indication that the lower voltage batteries are faulty
and should be replaced.
h. Following an 18-hour charge, the Battery Pack
should operate with a 10-ohm load for about 2.5
hours. The total battery voltage after this time should
be greater than +10 volts de.
i. If above tests indicate that battery capacity is
lower than normal, full capacity can sometimes be
regained by exercising the batteries through several
charge-discharge cycles. Batteries may be loaded
separately with 10-ohm, 25-watt resistors, for various
lengths of time, until the capacities of all batteries
are the same (all batteries measure 1.5 volts under
load, for example). In some cases, full capacity may
be obtained after charging the entire Battery Pack for
18 hours in the normal manner.
j. The battery pack should be checked and re-
charged every 30 days as part of a regular mainten-
ance cycle.
k. On days when the Battery Pack is used con-
tinuously for 3 to 8 hours (depending on plug-on
used), it should be recharged over night.
5-64. Replacing Internal Battery Supply
(see Figure 5-5)
5-65. If the procedure of Paragraph 5-62 establishes
that the 5310A internal batteries do not provide
power for the normal operating time, replace the
batteries. The batteries must be replaced with power
removed and battery pack separated from the 5300A
and plug-on used. Hewlett-Packard recommends
replacing
all
five
batteries.
Installing
only
one
new
battery
may
result
in
decreased
operating
life
of
the
older
batteries
or
the
newer
replacement
due
to
dif-
ferences
in
battery
capacity
with
age.
If
single
battery
5-15