HP 3562A, Service Manual

Page: 539 / 570

MOD E L 3S62A
S E RVICE
Failure
Type LEDs
-
B7
-
BS
1
9N
2
AN
3 DN
4 E N
S
OB
-
81
-
82
-
83
Table AB-l Global RAM Failures
Probable Fault
Description Location
Power-u p tests
-
and calibration
done; keys active
Starting G l obal
-
RAM test
G lobal data
G lobal Bus l i ne "N" (G DN)
bus fai lure
G lobal Bus Transceivers
bit "N"
(A8U609, U61 0), other
assembl ies on the global
bus
Memory address
A8 U21 1 , U1 1 1 , U61 1 ,
failure, bit "N"* U61 2
Repeatable Dynamic RAM chip
memory fai l ure,
assoc iated with fai l ing bit,
bit "N"
G DO thr,ough G D1 S
Nonrepeatable Dynam ic RAM chip
memory fai lure,
associated with fai l ing bit,
bit "N"
G DO through G D1 S, address
circu it, global bus
transceivers
G l obal RAM
Memory Refresh Tim er,
refresh failure
Arbiter, Refresh Address
Cou nter
G lobal RAM a l l
Memory control circu it,
bits failed, A8 U307, U308
both bytes
G lobal RAM a l l
A 8 U61 0, U307, U308
bits fai led, high
byte
G l obal RAM a l l A 8 U609, U307, U308
bits fai led, low byte
Further Tests
-
-
C hapter 7-S-F,
G lobal Bus Test
Table A8-9 #8
B.3.d
-
-
B.3. b, B.3.d,
B.3.e
B.3.b, B.3. c,
B.3.d, B.3.e
Table A8-9 #8, #9
Table A8-9 #8, #9
* I f the problem is after the m u ltiplexer, the L E Ds wi l l display only one of the two
address bits mu ltiplexed to the affected l ine.
8-89