HP 8508A - Page 121

MEE PRE RR RR RRR eRe eee
- Service
ERROR CCDES 200 SERIES
Errors
in
this
series
indicate
a
problem
with
the
Power
Supply
Assembly.
POWER SUPPLY ASSEMBLY A2
Summary
Description
.
=
The
power
supply
is
a
conventional
linear
circuit
design
that
provides
the
instrument
with
supplies
of
+5
Volts
and
+12
Volts.
Test
Points
and
adjustments
are
provided
on
the
Circuit
Board.
ae
AC Input three
+12 Volt
-12 Volt
Figure
8-4.
Simplifed
Block
Diagram
of
the
Power
Supply
Troubleshooting
A
fault
in
the
power
supply
will
be
indicated
by
a
display
of
an
Error
Code
in
the
200
series
and,
if
this
should
arise,
the
transformer,
supply
voltages
and
distribution
cables
should
be
checked
and
any
faulty
items
replaced.
Because
the
+12V
check
is
performed
using
the
Search
and
Lock
Assembly
(A4),
a
fault
on
the
Search
and
Lock
Assembly
(A4)
can
indicate
an
error
on
the
Power
Supply
Assembly
(A2).
Should
the
Error
Code
persist
the
defective
assem-
bly
should
be
replaced
with
a
new
one.
Disassembly and Reassembly Procedures
Removing the Power Supply Assembly
To
remove
the
Power
Supply
Assembly
from
the
Vector
Voltmeter:.
a. Wear 2 wrist strap for ESD protection.
b.
Remove
the
power
cord
from
the
instrument.
c. Remove the instrument top cover.
d.
Remove
the
nut
and
washer
securing
the
power
connector
Earth
lead
to
the
rear
panel.
e.
Remove
the
2
Nuts
and
Pozidriv
screws
securing
the
power
connector
to
the
rear
panel.
E1089
8-11