Platinum Z5 CD, Руководство пользователя, Страница: 168 / 194

6-16 888-2408-002
WARNING: Disconnect primary power prior to servicing.
Troubleshooting
If a PAC_REF fault appears along with the MSTR_REF fault, then the +5V
reference is most likely the problem. If only the MSTR_REF fault is present then
the Master Controller or a connection between the Life Support Board and the
Master Controller should be suspected. The +5V REF can also be checked at TP19
on the Master Controller Board. Note that CR11 will 5Vdc to TP19 if the
5V REF has failed, but with the diode drop it will be less than 4.6Vdc and
adjusting R28 on the Life Support Board will have no effect.
6.9.5 RFL_PWR, Reflected Power Fault
This fault is activated when the VSWR overload trip point is exceeded. This fault
will only show up if there is a large and quick change in the transmitter load
impedance or if the VSWR foldback setting is too close to the overload setting. The
VSWR overload should be set at 1.5:1 with the VSWR foldback setting normally at
1.35:1. A gradual change in impedance should be caught by the VSWR foldback
threshold and the RFL_PWR fault will not occur, although the transmitter may be
operating at a reduced power. If the 1.5:1 VSWR overload threshold is exceeded,
the transmitter will mute and then very slowly ramp the power up until back at full
power or until the foldback threshold of 1.35:1 is exceeded. The controller will now
try to keep the transmitter at its maximum power level while staying below the
foldback threshold.The Foldback light on the front of the controller will be
illuminated.
The VSWR Fault threshold is set via software in the Diagnostics Display Menu. To
check the VSWR Fault threshold press [CONFIGURATION B,D,C,C]. Caution,
this setting can be changed using the ABCD buttons to the right of the display. To
leave a screen without saving any changes, press [HOME]. The default for this
setting is 1.50:1. The VSWR foldback setting is under [CONFIGURATION B,D]
and should be 1.35:1. For all system calibrations refer to Section V, Maintenance
and Alignment.
It is also possible that a VSWR fault could be caused by a defective forward or
reflected directional coupler or simply from calibration error. An external reflected
power meter should be used to verify if there is really a VSWR problem or if it is an
internal sensor problem. Keep in mind that the reflected reading will be less than
200 watts when the transmitter is in foldback. This would barely be visible on a
5kW scale, but care should be taken to avoid overloading a lower power element.
6.9.6 INTLK, External Interlock Fault
This fault is activated anytime the External Interlock circuit is opened. An External
Interlock fault shuts the transmitter off by disengaging the main AC contactor.
There must be a closed contact between the external interlock connections in order
for the transmitter to operate. This fault also illuminates (not flashing) the Interlock
Fault LED on the controller front panel. See Table 2-1, “TB1 Remote Control
Interface Connections,” on page 28, for more information on External Interlock
Connections.