888-2406-002
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WARNING: Disconnect primary power prior to servicing.
Troubleshooting
6.11 PA Controller Faults
The following paragraphs give a detailed description of all faults associated with the
PA Controller Boards. This mostly deals with the PAs and Isolation resistors. A
quick reference of these faults is given in Table 6-2 at the end of this section.
6.11.1 General PA Troubleshooting
As a general rule, the first step in troubleshooting any PA (or IPA) problem is to
swap the PA or the entire module with another in the transmitter. If the problem
moves with the PA, you have verified that it is the PA and not the slot to which it is
connected. If the problem appears to stay with the particular slot, then more
advanced troubleshooting of the Z-Plane or cabling back to the controller should be
explored. This is where Table 4-1 on page 4-59 can save alot of time.
6.11.2 PA#_OC, PA Over-Current Fault
The PA Current overload threshold for each PA is nominally 14.5 amps, provided
there are no failed PAs. If an individual PA exceeds this current, the individual PA
will be switched out.. This optimizes the combiner for the other PAs until a
TX_RESTART is initiated by pressing one of the ON buttons. This will un-mute the
faulty PA. If the current is still too high, the PA will be switched back out again.
However, it should be noted that the Z2 control system is adaptive. With the failure
of one PA, the other 3 PAs in that foursome will have a reduced PA current foldback
level due to the increased VSWR. If a second PA fails, it depends on where it is
located in relation to the first one as to the action the controller will take when
reducing the current foldback limit on the PAs. Basically, this means that with 2 PAs
failed, the transmitter may be close to 90% power or it could be as little as 50%,
depending on the location of the failed PAs. See “Multiple PA Failures in a
Foursome” earlier in this chapter.
6.11.3 PA Current Foldback
The PA Current Foldback threshold is 13.4 amps. This means the PA Controllers
will try to foldback the power of a PA, to keep its current at or below 13.4 amps, by
making the PA gate voltage more negative. The PA Foldback current rating is a
moving target depending on the number of working PAs and VSWR. The PA
Current Foldback points can be checked using the Diagnostics Display by pressing
[METERING A,B,D].
Summary of Contents for Platinum Z2 CD
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Page 70: ...3 14 888 2406 002 WARNING Disconnect primary power prior to servicing Operator Guide ...
Page 130: ...4 60 888 2406 002 WARNING Disconnect primary power prior to servicing Overall System Theory ...
Page 194: ...6 38 888 2406 002 WARNING Disconnect primary power prior to servicing Troubleshooting ...
Page 196: ...7 2 888 2406 002 WARNING Disconnect primary power prior to servicing Parts List ...
