HP (Hewlett-Packard) HP 85660B ユーザーズマニュアル
100 MHz VCXO, Troubleshooting
The 100 MHz VCXO supplies all of the fixed reference frequencies for the HP 8566B. Separate
100 MHz outputs are routed to the
and
assemblies. A 400 MHz signal is
applied to the
assembly. The
assembly divides the 100 MHz input to provide 10
MHz and 20 MHz references.
100 MHz Oscillator
The tune voltage at
is nominally -8 V. If an unlocked condition exists, this voltage
is either -23 V or -1.3 V. If the level is -23 V, check the 10 MHz reference to
If the
level is -1.3 V, check the outputs of the 100 MHz Buffer/Amplifier.
Typical voltage levels for the oscillator transistor Q5 are:
Emitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Collector
Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Collector
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..O.O V
100 MHz Buffer/Amplifier
All 100 MHz output levels should be approximately 0
Typical voltage levels for each
transistor are as shown in Table 1.
Emitter
4.0 3.9
3.9
Base
4.7 4.7 4.6
Collector 9.3 9.4
9.4
Table 1. 100 MHz Buffer/Amplifier Voltage Levels
Quadrupler and 400 MHz Amplifier
Typical voltage levels for the Quadrupler and 400 MHz Amplifier are as shown in Table 2.
The 400 MHz Amplifier output at
(96 cable) is approximately -10
when the
100 MHz board assembly is in the casting.
Table 2. Quadrupler and 400 MHz Amplifier Voltage Levels
Q3 Q4
Q3
Emitter
-4.6 -5.1 -6.6 -6.6
Base
-5.9 -5.9 -5.9 -5.9
Collector
0.0
0.0
0.0
0.0
2