HP 3438A Operating And Service Manual page 63

Model 3438A Section V l l l
device participating in that particular conversation. 7-he
three Data BYTE Transfer CONTROL linesare used to
implement the handshake technique.
,fi'ngerprinrs rc,ill reduc,r the acc,urac:L, qf' rhe
Multitneter. L!se 1o~c.flux content solder (-hp-
Port N o . 8090-0512) tr,hen replac.ing
c.otli/~onerlfs. Do not permit rrac.e.s c?f:flux- t o
fOrtl! on the c.irc,uit hoard. Ohserve
/)recmirion.s ogoinst static discharge. Do nor
use flu..; rc/no\l(Jr.
8-50. T h e remaining five GENERAL INTERFACE
MANAGEMENT lines a r e used for such things as
activating all the connected devices at once, clearing the
interface, etc. Refer t o Table 8-3 for the definition of each
of the management lines.
8-53. F r o n t P a n e l Observations. W i t h o u t
disassembling the Multimeter, failures can often be
isolated by doing t h e Abbreviated Performance Tests
and by carefully observing a n d recording the display
indications. This is especially true if the failure is a
measurement error.
Table 8-3. General Interface Management Lines.
1
Name
1
Mnernonlc
1
D e s c r l ~ t l o n
1
1
Attent~on
Interface
Clear 8-54. Refer t o Table 8-4 A C Gain, 8-5 DC Gain. a n d
Figure 8-12. Simplified Analog Schematic for the
following examples.
ATN
IFC
IFC
Serv~ce
Request
Rernote
Enable
End of
ldent~ty
DETERMINES the Operaflng rnode
INITIALIZES the HP-IB system to a n idle
state (no act~vlty on the BUS)
SRQ
REN
ED1
ALERTS the Controller to a need f o ~
Commun~cat~on
PLACES Instruments under remote
program control
INDICATES last data transltlon
d u r ~ n g a data transfer sequence
NOTE
Circled letters
@
through
@
are reference
/ J O ~ ~ / S
to aid in carrelaring berween hlocYi,
simplified, ant1 comple~e sc.hemaric diagrams.
Table 8-4. AC Gain.
@
@
TROUBLESHOOTING
8-51. Preliminary Troubleshooting.
l n p u t
1 0
v
l n p u t A m p
[Gain)
8-52. Troubleshooting procedures a r e performed after it
is established that there is a failure in the Multimeter
circuitry. Unless a failure is obvious, such as a blank
display, refer t o the Adjustment Procedures a n d
Abbreviated Performance Checks before attempting t o
troubleshoot the Multimeter.
The h17hrid c.irc.uit.s in the Multimeter m
yr.
he
~~ert1lunet~t~r' clotnaged hy .sta~ic discharge
Jrotn a hantl or tool when the Mulritneter is
disassetn bled. The proceclures hrlo w must be
,followed to prevent possible damage.
Table 8-5. DC Gain.
@ @
I. Ground the hand while disassemhling
and working on the Multitneter. Conductive
w~risthands (-hp- Part No. 00970-67900) are
ovailable~for this purpose.
2. Attac,h rile Multimeter COM tertninal
to earth ground. Touch all tools lo earth
ground to remove sturic charges hefore usit~g
thrt~l on the Multitneter.
Range
2 0 0 m V
8-54(a). 100 kHz frequency response failures are most
often associated with t h e a c to d c converter of the post
a m p
x
10 gain. This failure can also be isolated by
recording and evaluating the ranges that a r e in or out of
specification.
l n p u t A m p
(Gain)
X I
l n p u t
Voltage
l 0 0 m V
3. Clse o .soldering iron tc3ith a grounded ti/,.
Ilfear c./ean c.ottot2 g1ove.v tc'herz tt.orking on
t h e c,irc,uit hoard. C o n t o t ~ i i n a t i o n or
Post A m p
(Gain)
X
1 0
Example 1:
Post A m p
O u t p u t
1
v
O U T
O U T