Fluke PM6681 - Page 70

Introduction
Power
Supply
Required Test Equipment
Type
Performance
Model No
DMM 5 full digits PM
2534
Counter
PM 6669
DC
source
5
V Philips
PE
1536
LF-synthesizer 10 kHz/20
Vpp PM
5193
S
PC incl. CRC
GPIB
interface
_**
Interpolator
Calibration
program
**
(incl.
in
this
manual)
Pulse
Generator
125
MHz/2ns
PM 5786
(PM
5781**)
Signal generator 1300 MHz
6062A
Sampling oscilloscope
FET probe
Passive probe 10:1 <1.5 pF
PM 8926
Terminator
50 £2/1 W
PM9585 or
Y9103
Attenuator
20 dB PM
9591 or
Y9102
Power splitter
50 n/4W
PM 9584
T“piece
PM 9067;
Y9107
10 MHz
reference X o
PM 9691
10 MHz
reference
X o PM
6681 R or
PM6685R*
BNC-BNC cables
Insulated screwdriver
Table
6-1
Required Test
Equipment
*
For
adjustment
of Oven Oscillators only.
**
PM
5781 required for
Interpolator
calibration
adjustment.
Preparation
WARNING:
Live parts and
accessible
terminals
which
can be dangerous
to
life are always
exposed
inside the
unit when it is
connec-
ted to
the iine
power.
Use extreme
caution
when
handiing, testing,
or
adjusting
the
counter.
Before beginning
the
calibration
adjustments,
power
up the
instrument
and
leave it on for at
least 60 minutes to
let it
re-
ach
normal
operating
temperature.
CAUTION: If
you
adjust the
+5V trimmer you
have to adjust the
complete
instrument.
•
Setup
-
Connect the counter
to the iine
power.
-
Switch
on the
counter.
-
Press PRESET, then press
ENTER.
Figure
6-1
Test
points and trimmer
for the Power
Supply.
•
Adjustment
-
Connect
the
DMM to test points
L10 and GND6, see
Figure
6-1.
-
Adjust the
+5V
trim
potentiometer
R446=+5V
adjust in
the power supply
using an insulated
screwdriver, until
the DMM reads
+5.000 +0.001 V.
-
Check
that the
voltage at the test
points
X15=+5 and
GND6 is
+5.00
±0.05
V.
-
Check that the unregulated
voltage
from the power supp-
ly at test points XII
=+15
and GND6 is about
+18
V.
-
Check that the
unregulated
voltage from the
power
supp-
ly
at
test points X12=-9 and
GND6 is
about
-8
V.
6-2
Introduction