Wavetek 188 - General Instructions

2. Opened capacitor can be located (but not always)
by
using
a good
capacitor connected
in parallel
with the capacitor under test and observing the
resulting effect.
Once the malfunction is defined, begin the isolation
procedure by selecting an indication in table
6-1
which
best
describes
the malfunction and proceed to
the referenced troubleshooting table.
6.4
GENERAL INSTRUCTIONS
When encountering a problem, it is
advisable
to
return
as
many
of
the front panel controls
as
possible
to
their
initial settings and still retain the problem The trouble-
shooting tables In this section generally begin at these
Initial settings and specify all subsequent setups
Preset the
front
panel controls
as
follows
Control
Frequency Dial
POWER
FREQ MULT (Hz)
FUNCTION
DC
OFFSET
AMPLITUDE
SWEEP
Position
40
..
ON
IK
'V
OFF
MAX
CONT.
STOP.
LIN
CAUTION
To prevent damage to
components, turn
unit off while romoving or replacing
components, connectors or pc boards.
Tho
suspected
malfunctioning condition should
be
double chocked
to
eliminate the possibility of improoer
settings or connections Before attempting
fault isola-
tion, tho unit should be
checked for proper line
voltage selection (refer
to
Section
2).
A
good
visual In-
spection of the boards and chassis
wires for damage
or overheating often saves
much time
Follow through the checks in the troubleshooting table,
using schematics and assemblies
as a
guide. When
positive results are not obtained, perform the in-
dicated corrective procedure
Table 6-1. Fault Isolation
Indication Table
1.
Fuse blown, no power indication or no
outputs 6-2
2
Function outputs
missing
or
clipped
when
TTL
sync
OK
Triangle problem
6-3
3.
Sme waveform problem
6-4
4
Square waveform problem 6-5
5
TTL sync output problem
66
6
Generator frequency
does nol
respond
correctly
to
dial and
VCG
input
6-7
7.
Waveform symmetry problem 6-8
8
Problem on bottom three ranges only.
6-9
9
Generator trigger and
gate
mode prob-
lem
6-10
10. Sweep
problem
6-11
Table
6-2.
Power Supplies and Generator Loop
Indication: Fuse blown
.
no power indication or no outputs
Check Corrective Procedure
1 . Set
all controls in their initial
positions
(refer
to
paragraph
6 4)
2. Ensure line voltage matches instrument configuration (refer to Section
2).
Check fuse.
Replace fuse; check
for nor-
mal operation.
3.
Check
Cl
( + )
and
C2
(
- )
for
± 20 to 26V
unregulated
dc. a
CRi
-
CR4
b. C1.C2
c SW1.
d.
Ti. RVi
,
Fi (bracket as-
sembly)