HP 8901B

Help 3-9
1. Check tuning mode. ~
Refer to lncreaslng
Selectivity (3-5) or
Drifty Carrier (3-6).
Check modulation
source.
2. Check calibration
(3-2).
Increase input
signal level.
NO Error
If the error goes away after the AUTOMATIC OPERATION key has
been pressed,
the error was caused by an operating problem. Look
up the error code in Table 3-1 and take the action recommended for
“Operating Problem”.
~ Recheck operating
conditions being used.
Decrease RF
attenuation.
New Error
If the error is replaced by a different error or dash code after the
AUTOMATIC OPERATION key has been pressed, the original error was
being caused
by a combined input problem and operating problem.
Look
up the error code displayed by the instrument after the
AUTOMATIC OPERATION key was pressed. Take the action recommended
for
“Input Problem“.
Questionable
Measurement
Remember
Because of the wide variety of input signals and the operating
flexibility of the
HP 8901B, it is not possible to list all
recovery actions for each error code. After using the table
to
determine the cause of the problem, you may discover other error
recovery procedures
that are better suited to your application.
1. Measurement is very inaccurate.
2. Measurement is slightly inaccurate.
Table 3-1 Modulation and Audio Error Codes (1 of 2)
--
or
0 MHz
----
01
02
03
04
Display
Code
Problem Description
Input signal level below measurement range.
Instrument has detected an input signal
and is attempting to set up measurement.
Continuous display indicates instrument is
having difficulty tuning
to the input signal.
IF signal within IF passband but not cen-
tered well enough to guarantee measure-
ment accuracy (due to manual tuning).
High AM depth (>95%) on low-level carrier.
Input circuits overdriven.
Input circuits underdriven.
Modulation level on input signal
exceeds modulation range limit.
Manually tune to
input signal. Refer to
Noisy Carrier (3-5).
Re-check operating
conditions being used.
Input Problem I Operating Problem
Increase carrier signal
level or decrease AM.
Increase RF
Press the MHz key
to center
IF signal
in IF passband.
If problem persists,
signal may be
drifting. Refer to
Drifty Carrier (3-6).
input attenuation. I
Increase aain. I Decrease RF
level on input
signal to within Function
k~.
setting, S ecial