Front Panel Overall Assembly-Level Troubleshooting - HP 8340B Manual

Front Panel
Overall Assembly-Level Troubleshooting
INSTRUMENT PRESET
1.
Disconnect all cables from the synthesizer.
2.
To
cycle the
power,
turn the power switch to standby, wait several minutes for all power supply capacitors to
discharge, and turn the power switch to on.
3.
Press [INSTR PRESET] and compare the instrument configuration
with the following:
Start Frequency:
10MHz
Stop Frequency:
26.5 GHz (HP 8340B)
20.0 GHz (HP
8341 B)
Power Level:
0.0 dBm (factory set value)
Can be changed with calibration constant 56.
Sweep Time:
AUTO (44.15
ms for
HP 8340B;
33.316
ms for HP 8341B;
press
[SWEEP TIME]
to
verify)
Sweep:
CONT
Trigger: FREE RUN
RF:
On
Leveling:
INT
INSTR CHECK
LEDs:
Off
Either or Both INSTR CHECK LEDS are On
If
either
or
both of the
INSTR CHECK LEDs
stay on after power on or an instrument preset, refer to the overall
instrument troubleshooting in the service introduction of this
manual.
Front Panel Diagnostic Mode Activates
If, at
power
on, the
front panel goes into the front panel diagnostic mode (the same as pressing [SHIFT] [FREE
RUN]), suspect the
main
instrument processor.
At power
on, the instrument microprocessor should initiate
a
self test. One
of the first things the
self test
does
is
send data to the front panel processor.
If
the front panel processor does not receive the data from the instrument
microprocessor,
it
automatically goes
into the diagnostic mode.
All
Front Panel LEDs are On
If,
at power on, all front panel
LEDs are on (similar to holding [INSTR
PRESET]), check the negative
power
supplies.
The
main instrument processor requires both the positive and negative supplies (and will
suspend
instrument functions
if
one is inoperative).
The front
panel LEDs require only the positive supplies.
LED AND ANNUNCIATOR TEST
1.
Turn the power switch to on.
2
Press and hold
[INSTR PRESET].
G-6 Front Panel Overall Assembly-Level Troubleshooting
HP 8340B/41B