5-19. Channel B Adjustments; 5-21. Troubleshooting; 100 Mhz Channel Troubleshooting - HP 5305 B Operating And Service Manual

Model 5305B
Maintenance
k. Slowing increase generator output level and observe
counter display. 5305B must never count 00180.XXX
MHz. If it does, adjust A1R71 cw until count light (C)
stops blinking.
l. Set generator output to 1.29999999 GHz at -21 dBm as
measured on power meter. 5305B should count
01299.999 MHz ±1 count.
m. Reduce generator level until counter barely counts
01299.999 MHz ± 1 count.
n. Adjust A1R71 cw if 5305B ambiguity is greater than ±1
count.
o. Adjust A2R22 cw until counter barely counts
01299.999 MHz ±1 count.
p. Input power to 5305B should be ≤ -21 dBm.
q. Set input level to -21 dBm and scan frequency down to
90 MHz. Counter should display same reading as
8660B ±1 count.
r. Set generator to 90 MHz at -5 dBm.
s. Connect 5306A voltmeter to TPG and adjust
A2R13 cw until 5306A reads +12V ±1V.
9E-5-19. CHANNEL B ADJUSTMENTS
9E-5-20. The following steps outline proper adjustment
procedure for Channel B amplifier.
a. On 5305B, set RANGE to B and RESOLUTION to
1 Hz.
b. Set A1R44 to midrange and A1R18 to full cw.
c. Set 651B Test Oscillator to 50 Hz at 3V rms and
connect directly to 100 MHz input on 5305B.
d. Measure AGC voltage at TP A with 5300B/5306A
voltmeter.
e. Adjust A1R44 for 1.75V reading on voltmeter.
SERVICE NOTE
AGC voltage should decrease when level
of input signal is reduced. With no input
signal, AGC voltage should be negative.
f. Disconnect 651B Test Oscillator.
g. On 5305B, set RANGE to B and RESOLUTION to 10
Hz.
9E-5-6
h. Set 8660B/86602A Signal Generator to 100 MHz at
±2mV and connect output of generator to 100 MHz
input using a 50-ohm feed-thru.
i. Increase generator level until counter displays stable
MHz ±1 count.
J. Adjust A1R18 ccw to point where 5305B barely continues
to make measurements. (Any more ccw rotation will stop
gating.)
k. Input signal must be 20 mV or below.
9E-5-21. TROUBLESHOOTING
9E-5-22. Use the following troubleshooting information, the
waveforms, and schematic diagram in subsection VIII to
isolate troubles in the counter to a defective component.
9E-5-23. If a malfunction is suspected, operate the counter
in the self-check mode (see Figure 9E-3-3) and analyze the
front-panel indicators for evidence of improper operation.
Some troubles can be quickly isolated in this manner. The
self-check procedure exercises most of the counter circuits; the
input circuits for both channels are notable exceptions.
9E-5-24. To determine if a problem exists in both input
channels or just one channel, then perform the appropriate
troubleshooting procedure. Be sure to perform each step in
sequence. The following test equipment is required:
a. HP 10525T Logic Probe
b. HP 180A/1801A/1821A Oscilloscope
c. HP 651B Test Oscillator
d. HP 8660B/86602A Synthesized Signal Generator
9E-5-25.

100 MHz Channel Troubleshooting

9E-5-26. Set the RESOLUTION switch to 1 kHz and the
RANGE switch to 100 MHz. Supply a 9 kHz, 1-volt
sinusoidal input to the channel. Perform the following steps:
a. Check output of Channel B at A1 U6(3). See wave form
photos in Subsection VIII.
b. If proper signal is not present, compare waveforms with
those provided in Subsection VIII.
c. If proper signal is present, check operation of U12C.
100