Table of Contents
Advertisement
Model 654A
Section V
odel654A
Ir-
Je
Ie
es
e the wave
.
and g to
at 5MHz,
below the
e the wave
I
indicated
d measure
4dB below
l-5 I if the
igure 5-11.
) build the
Clockwise
..... XIK
.... +10,0
iO
UNBAL
AC VOL TMETER
TEST OSCILLATOR
hp400E
hp654A
rEll
.
@
o
~~
~d
f...JJ
"I
50n FEED-THRU
.,•••
-
~~
- -
-,~;~~~~
- - - -JG'-B_ _ _
T _ E - o ~ : n I ~ _ : ~ _ : l : ~ Q j I C I - ° _ N
_ _
--,J
:
SEE
~11~0~RE
5-12
:
I
I
k
_
_____________
~
Figure 5-11. Hum
and
Noise
Check
c. Adjust the
654A
AMPLITUDE
control
for an
ac
voltmeter indication of OdS on the OdB range.
IN THE FOLLOWING STEP THE
654A
TUNER CAPACITOR IS SHORTED TO
GROUND. CARE SHOULD BE TAKEN
NOT TO TOUCH OR DAMAGE THE
PLATES OF THE TUNER CAPACITOR
OTHERWISE THE INSTRUMENT WILL
HAVE TO BE RECALIBRATED.
DO NOT MOVE THE TWO WIRES BE-
TWEEN TUNER AND RANGE SWITCH
(95 AND 8): THEIR POSmON WILL
EFFECT FREQUENCY. ALL WIRES
ON OR AROUND THE FREQUENCY
RANGE
SWITCH
CAN EFFECT FRE-
QUENCY RESPONSE.
a
W
§ - l
+3.0
<[w
>
Ww
CD
-l
t2.5
ou
1--
UJ~
+
2
.
0
-l~
Wa:
~<[
+1.5
UI
W
atn
tl.O
lLw
o(!)
Ei~
+0,5
CD-l
::Eo
~I-
\
o
\
'\
\
1,\
l"-
I'-.
'"
r-.....
t--
t--
l -
t-
o
-2
-4
-6
-8
-10
-
12
-14
16
DECI BEL
01
FFERENCE BETWEEN TWO VALUES
Ie 5-12. Logarittunic Addition of Hannonic Components
d.
Remove the
654A
top
cover:
insert
a screwdriver
between the tuner
capacitor
(point X
on
Figure
5-14) and
chassis
ground.
The residual hum
and
noise indicated on the
ac
voltmeter
should be
greater
than 70d B
below
the Od B reference.
10MHz LOW
PASS FILTER
,---
-
-
------------------
-
-
--
-
,
I
I
I
LI
L2
L3
L4
I
I
.82jJH
.68jJH
.68jJH
.82jJH
b
I
1
C2
C3
J
C4
CI
I
~'20PF
~470PF
470PF~
1
20PF~
I
I
I
L
- - - -
- -
-
- -
- -
- -
;
---------
.;;;.~._.i
J
ct
~
CI,C4,
Capfxd:
120pF+/
-5
%
-hp- 0160-2205
C2,C3.
Cap fxd: 470pF
+/-5%
-hp- 0140 -0149
Ll.L4,
Ind fxd: 0.82uH
+/
-10%
-h p-
91
00-1
6
14
L2,L3,
Ind fxd:
0.68uH
+/-15%
-hp-
9140-0024
Figure 5-13. JOMHz Low
Pass
Filter
e.
If the tolerance
is
not met ensure thai
a good
ground
connection
was
made in
step
d before
troubleshooting the instrument.
5-37. COUNTER OUTPUT CHECK.
a.
Set the
654A controls
as follows:
FREQUENCY dial
.
.
...
1
FREQUENCY RANGE
XIO
b. Connect an
ac
voltmeter to the
654A rear
panel
COUNTER OUTPUT; terminate the the cable to
the
ac
voltmeter with a SO
ohm
feed through
termination.
c.
Sweep the FREQUENCY dial slowly
from
I
to 10
for all positions
of
the FREQUENCY RANGE
switch.
5-1
I
Advertisement
Table of Contents
