12/20/11
888-2595-001
4-19
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ZX Series
Similar functionality is provided for PA modules 2 through 8 by the remaining positions
in U22, U23, U1, U2.
In addition to the total PA stage current, the current of each individual PA module may
be read by means of a series of selector pushbuttons whenever the meter is already in
the PA AMPS position. These switches are located on the reverse side of the controller
board and may be accessed by opening the front door to the amplifier chassis.
Pushbutton switch S1 activates analog switch U3A and passes the PA1_AMPS sample
to the ONE_PA_AMPS signal line, provided that switch S15A is in the ON position.
Switch S15 allows the pushbuttons for non-populated module positions to be
deactivated in transmitter models without the full complement of modules installed.
Steering diode CR2E also passes a logic high level via ONE_PA_MTR to SPDT switch
U17 (page 5), thereby causing a substitution of the ONE_PA_AMPS reading (in this
case, PA1 AMPS) for the total PA_AMPS reading to be passed on to the meter via U7A.
Pushbuttons S2 through S8 and the remaining positions of U3, U4 provide similar
functionality for PA modules 2 through 8.
4.12.5 Fault and Status Signaling
(page 6) Front panel tri-color LEDs DS1, DS2, and DS3 assume one of three states
depending on the current operational status:
Green: transmitter is on and no faults are present
Yellow: transmitter is on but faults are present
Red: transmitter is off
Only one of these three LEDs will be lit, according to the current operational mode:
FM Mode: DS1
FM+HD Mode: DS2
HD/SL Mode: DS3
The green segment of LEDs DS1-DS3 is lit from the TX_ON_STAT line via current
limiting resistor R22 and analog switches U9A, U9B, or U9C, depending on the current
mode. The TX_ON_STAT line will be high whenever the PA_VOLTS sample reports a
PA voltage greater than approxi25V as determined by comparator U26A and
voltage divider R80-R100 (page 4).
The red segment of LEDs DS1-DS3 is lit via any one of a variety of fault conditions via
diode-or network CR3. If the green segment is also lit (i.e. PA volts present), an
orange-yellow output will result. If the green segment is not lit, a red output will result.
Summary of Contents for ZX2500
Page 2: ...ii 888 2595 001 12 20 11 WARNING Disconnect primary power prior to servicing...
Page 4: ...iv 888 2595 001 12 20 11 WARNING Disconnect primary power prior to servicing...
Page 6: ...MRH 2 888 2595 001 12 20 11 WARNING Disconnect primary power prior to servicing...
Page 8: ...viii 888 2595 001 12 20 11 WARNING Disconnect primary power prior to servicing...
Page 9: ...12 20 11 888 2595 001 ix WARNING Disconnect primary power prior to servicing...
Page 10: ...x 888 2595 001 12 20 11 WARNING Disconnect primary power prior to servicing...
Page 14: ...xiv 888 2595 001 12 20 11 WARNING Disconnect primary power prior to servicing...
Page 18: ...Table of Contents Continued 4...
