i.
Twist together one of the two wires connected to pin
15
and the wire connected to pin
14.
These are
the oven controller power supply inputs.
j.
Twist together the remaining wire connected to pin
15
and the wire connected to pin
11.
This is the
oven monitor output.
k.
Twist together the two wires connected to pins
2
and
3.
These are the oscillator supply inputs.
1.
Connect one banana plug to the free end of each wire.
m. Label each banana plug
as
follows:
Wire
connected
to:
pin
2
pin
3
Label
as:
oscillator supply
(
-
)
oscillator supply
(+)
pin
11
oven monitor
(
+
)
pin
14
oven supply
(
+
)
pin
15
(two wires)
oven monitor
(
-
)
n.
Inspect the connector for poor solder joints, bent, or damaged pins. Double check the labeling of the
plugs to be sure the polarity markings are correct. If the voltages are connected the wrong way,
damage to the oven oscillator may occur.
8-390.
Types
of
Failures
8-391.
Failures in the oscillator unit can be divided into two sections:
a.
Failure of the oscillator's circuits.
b. Failure in the oven controller circuits.
8-392.
Failures in the oscillator circuits can be divided into the following problems:
a. No output.
b.
Output amplitude is too low or too high.
c.
Output frequency is too low or too high.
8-393.
Poor frequency stability can be difficult to troubleshoot and many times the oscillator is not at fault. En-
vironmental conditions can affect stability and should be ruled out first.
8-394.
Failures in the oven circuitry can be divided into the following problems:
a. No oven current (heat).
b.
Excessive oven current
(
>
600
mA).
c. Oven does not cut back after warm-up (this will open the thermal fuse
if
allowed to continue).
8-395.
Since the main oscillator and oven control power supply inputs are separate from each other, the defec-
tive circuit can be operated without applying power to the complete oscillator.
8-3%.
Determine which section is defective (oven or oscillator circuit), then proceed as described in the follow-
ing troubleshooting section. The two circuits can be investigated separately.
HP
5334B
-
Service Manual
8-57
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