Model 8901B Service
0
Front-Panel
LED
Check
Procedure:
Disconnect any connection to the INPUT connector. Switch POWER to STBY and
back to ON.
Normal Indication:
After less than one second, all front-panel LEDs and display segments
and decimal points should light for about 10 seconds. The display should blank for one second,
then show
“--”
with the MHz annunciator. The FREQ key, the AUTO TUNING, and the FM
MODULATION OUTPUT annunciators should all light. This indicates that the Controller
is
able to output to the front-panel LED and display latches which are all operative.
If Indication Abnormal: If
one
or
more LEDs
or
display segments fail, check the respective
components and drive circuits. (See Service Sheets 26 and
27.)
Also check the CPU
1/0
port.
(See Service Sheet BD5.)
@
Measurement Error Check
Procedure:
Key in 43.1 SPCL to enable Service Errors. Make the measurement in which the
fault appears.
Normal Indication:
As the Special F’unction code
is
entered, 43.1 should appear in the display.
This indicates that the Controller responds to keyboard interrupts. After pressing the SPCL key,
measurements should proceed as normal.
If Indication Abnormal:
If
the keys have no effect, check the Keyboard interrupt. (See Service
Sheet 25.)
If
the keystrokes produce an erroneous display, check the Keyboard. (See Service Sheet
BD5.)
If
the measurement is improper
or
error messages appear in the display, consult the error
message tables (see
Error
Messages
in the
Detailed Operating Instructions
of
the
Operation and
Calibration Manual,
or
see
Error
Messages,
paragraph
8-8,
or
see
Error
Codes
in the
Operating
Information
pullout card)
or
consult the block diagram service sheet that documents the section
of the instrument that appears to have the fault. (See Service Sheets BD2 through BD5.)
NOTE
For problems that are exclusive to the HP-IB, see Service Sheet BD5.
Service Sheet BD1 8D-13
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