HP 3478A Technical Manual page 90

3478A 3478A
Figure 7-D-5. 5. U462 ALE Figure 7-D-
Other failures are normally noted when, after doing a Other failures are normally noted when, after doing a
Self-Test, the 3478A display's either "A:D SLOPE ERR" Self-Test, the 3478A display's either "A:D SLOPE ERR"
or "A:D TEST FAIL". If an "A:D LINK FAI or "A:D TEST FAIL". If an "A:D LINK FAIL" is displayed,
the failure is most likely in the Isolation Circuitry (go to the failure is most likely in the Isolation Circuitry (go to
paragraph paragraph 7-D-44 7-D-44 for for troubleshooting).
paragraphs have the failures and troubleshooting paragraphs have the failures and troubleshooting
information for the A/D Converter. information for the A/D Converter.
7-D-37. Overload, Constant 7-D-37. Overload, Constant Zero, Floating,
Readings. . Before troub Readings Before troubleshooting the
these failures, make sure the failures are not caused by these failures, make sure the failures are not caused by
the 3478 the 3478A's I A's Input Circuit nput Circuitry.
follows this paragraph (the same procedure is also in follows this paragraph (the same procedure is also in
Service Group A). Service Group A). If the pro If the procedure has been
already, ig already, ignore the pro nore the procedure and go cedure and go to to Flowchart D for
troubleshooting. If it troubleshooting. If it has not has not been performed,
following: following:
a. a. Set Set the the 347 3478A to t 8A to the DC V
Range. Range.
b. b. Turn A Turn Autoz utozero o ero off by
ton and then the INT/TRIG (AUTOZERO) button. ton and then the INT/TRIG (AUTOZERO) button.
c. c. App Apply a st ly a stabl able + 3V d e + 3V dc to t
d. d. With a With a Dig Digita ital Vo
measure for + O1V at JMIOI. measure for + O1V at JMIOI.
e. e. If th If the rea e readin ding on th g on the tes
10V, the 10V, the A/D Conver A/D Converter is ter is at fault.
troubleshooting. troubleshooting. If the reading If the reading is other than
Service Group A for troubleshooting. Service Group A for troubleshooting.
7-D-38. A/D 7-D-38. A/D Slope Slope Error Error. . When an
is displayed on the 3478A, the most likely cause is the is displayed on the 3478A, the most likely cause is the
A/D Converter (U403 and associated circuitry) or the A/D A/D Converter (U403 and associated circuitry) or the A/D
Controller Controller (U462). (U462).
troubleshooting. troubleshooting. The pro The procedure
the different ports (using Signature Analysis) of the A/D the different ports (using Signature Analysis) of the A/D
Controller (U462) and also checks the DAC (U465). Controller (U462) and also checks the DAC (U465).
7-D-39. A/D 7-D-39. A/D Test Test Falls Falls. . If If the
FAIL" is displayed, the A/D Converter fails its internal FAIL" is displayed, the A/D Converter fails its internal
test. test. Since this can be caus Since this can be caused by the A/D Cont
U462 ALE Signal Signal
L" is displayed,
troubleshooting). The follow The following
Zero, Floating, or Noisy
leshooting the A/D Converter A/D Converter for
ry. Do the Do the procedure w procedure which
cedure has been performed performed
Flowchart D for
been performed, do the
he DC Volt olts Fun s Functi ction an on and 3V
ff by press pressing t ing the bl he blue Sh ue Shift bu
c to the I he INPU NPUT Ter T Termin
l Voltm ltmete eter (l r (like t ike the 34 he 3456A
e test vol t voltme tmeter i ter is a stab s a stable +
at fault. Go to Go to Flowchart D Flowchart D for
is other than + O1V, go to + O1V, go to
When an "A:D SLOPE "A:D SLOPE ERR"
Go Go to to Flowchart Flowchart
cedure in t in the he Flowchart Flowchart checks
the message message "A:D "A:D TEST
ed by the A/D Controller roller
(U403 and associated circuitry) or the A/D Controller (U403 and associated circuitry) or the A/D Controller
(U462), go (U462),
procedure in the procedure
(using Signature Analysis) of the A/D Controller and also (using Signature Analysis) of the A/D Controller and also
checks the DAC (U465). checks the DAC (U465).
7-D-40. Input Hybrid 7-D-40.
7-D-41. An inoperative 7-D-41.
the hybrid itself or when it receives wrong information the hybrid itself or when it receives wrong information
from the A/D Controller. from the A/D Cont
following: following:
a. a. Tu
b. b. Mov
"D" position (JM403 pin 1 and 2), as shown in Figure 7- "D" position (JM403 pin 1 and 2), as shown in Figure 7-
D-7. D-7.
ing
c. c. Obt
as follows (shown in Figure 7-D-7) as follows (shown in
or Noisy
S S t t a a r r t t : :
for
S S t t o o p p : :
hich
C C l l o o c c k k : :
H H o o l l d d : :
Self-Test: Out Self-Test: Out
G G n n d d : :
do the
d. d. Tur
signatures: signatures:
d 3V
U462 pin 32: 7ACA U462 pin 32: 7ACA
U462 pin 33: 20FO U462 pin 33: 20FO
U462 pin 34: 666H U462 pin 34: 666H
ift but- t-
e. e. If a
defective. Go t defective.
minals als. .
f. f.
defective. defective.
56A) )
7-D-42. A/D Controller 7-D-42.
le +
7-D-43. 7-D-43. Do the
for
(U462). (U462).
a. a. Usi
RESET line (U462 pin 4) is high. RESET line (U462 pin 4) is high.
ERR"
b. b. If t
D D for for
checks
may may be
TEST
troubleshooting. troubleshooting.
pin 3. pin 3.
7-D-8 7-D-8
go to to Flowchart D D for Flowchart
in the Flowchart Flowchart checks the
Input Hybrid (U102) Inope (U102) Inoperative
An inoperative Input Hy Input Hybrid can be
roller. To isolate the circuit To isolate the circuitry, do t
Turn rn th the 3 e 347 478A 8A of off. f.
Move jump e jumpers J ers JM50 M502, JM 2, JM503
Obtain ain a S a Sign ignatu ature re Ana Analy lyze
Figure 7-D-7): :
T T P P 4 4 0 0 1 1 ( ( J J M M 4 4 0 0 3 3 p p i i n n 6 6 ) ) ( (
T T P P 4 4 0 0 2 2 ( ( J J M M 4 4 0 0 3 3 p p i i n n 5 5 ) ) ( (
T T P P 4 4 0 0 3 3 ( ( J J M M 4 4 0 0 3 3 p p i i n n 4 4 ) ) ( (
O O u u t t
G G r r o o u u n n d d P P in in ( ( n n e e x x t t t t o o C C 2 2 0 0 3 3 ) )
Turn the n the 347 3478A on a 8A on and ch
If any ny sig signat nature ures are w s are wron
Go to o Flowchart Flowchart D f D for t
If the s If t he sign ignatu atures res are are goo
A/D Controller Troubleshooting Troubleshooting
Do the following to following to check the A/D
Using a lo ng a logic p gic prob robe, ch e, check an
If the RE he RESET l SET line i ine is low s low, do t
1. 1. Mak Make su e sure p re pin 1 in 1 of U of U462
2. 2. If p If pin 1 in 1 is no is not t t togglin oggling, t
be at at fault. fault. Go to to paragraph Go
3. 3. If p If pin 1 i in 1 is tog s toggli gling, ng, che
TM 11-6625-3071-14 TM 11-6625-3071-14
for troubleshooting. troubleshooting. The The
checks the different port different ports s
rative
brid can be caused by caused by
ry, do the
503, an , and JM4 d JM403 to t 03 to the
zer. r. Set Set and and con connec nect t
) )
) )
) )
nd check fo eck for the f r the foll ollowi owing
rong, U4 g, U462 ma 62 may be y be
or troubleshooting. roubleshooting.
good, t d, the I he Inpu nput Hy t Hybri brid is d is
check the A/D Controller Controller
eck and make d make sur sure the e the
, do the fo he follow llowing ing: :
462 is t is togg ogglin ling. g.
g, the I he Isolat solation C ion Circuit ircuitry ry
paragraph 7-D-44 7-D-44 for
check fo ck for a lo r a low at U w at U466 466
he
he
ng
for