Fluke 8840A - IEEE-488 Interface Troubleshooting

Maintenance
TROUBLESHOOTING
2. Release the two nylon latches that hold the IEEE-488
CAUTION
Interface PCA in place by pulling the latches upward.
To avoid damage to the 8840A or other
3. Position the IEEE-488 Interface PCA vertically as
equipment, the 8840A must be discon-
shown in Figure 6-19 and latch it in place be pressing
the two nylon latches into the mounting supports
nected from all other IEEE-488 interface
specially provided on the chassis.
instruments while the diagnostic pro-
gram is running.
6-70. DIAGNOSTIC PROGRAM
To facilitate troubleshooting, the IEEE-488 Interface pro-
1. Ensure the 8840A POWER switch is OFF.
vides a diagnostic program which places the instrument in
known configurations. To initiate the diagnostic program,
2.
Disconnect all cables from the rear panel IEEE-488
- - -
proceed as follows: connector.
r
-
1
-
Figure 649. Option -05 Service Position
Table 6-24. Diagnostic Modes
CONFIGURATION
SWITCHES
Static, odd-port bits = 1, even-port bits = 0
Static, odd-port bits
= 0, even-port bits = 1
0 X
-
-
NOTES:
"x" means switch setting does nol: matter
"Static" means the Out-Guard
WC VO port bits programmed as outputs are driven to a constant logic 1 car 0
level (as defined by switch
A2).
"Dynamicw means the Out-Guard PC 110 port bis programmed as outputs are driven with a 610 Hz, 50%
duty cycle square wave. All odd
port bi numbers are 180 degrees out of phase with even port bi numbers.
"ReadNVriten means that data is read from and wriien to the NEC7210 IEEE chip
(U901) when DS (U901-8)
is low.
FUW (U901-7) determines whether the data is being read from or written to the NEC7120. The
address
bits are always 3 (0011) and the data bits are incremented each time.
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