Motorola HT-1000 Service Manual page 47

UHF, 403-470MHz Radios
UHF, 450-520MHz Radios
VCO varactors (CR201, 202, and 203) in "C" and later kits are not
interchangeable with VCO varactors in earlier kits; Motorola parts and
part numbers are different. When replacing a VCO varactor, Identify
the transceiver board and order replacement parts from the applicable
parts list.
UHF transceiver board (403 - 470MHz band split) NUE7231 and
NUE7240 ("C" and later) kits include new VCO varactors, and are
factory aligned with a new transmit VCO crossover frequency of
449.500MHz.
Since the transmit crossover frequency has changed, whenever
transmit VCO crossover alignment (an RSS function) is performed,
UHF band split and circuit board identification will be important.
• UHF band split can positively be determined by checking the
markings on the power amplifier shield. If the power amplifier
shield marking is 25U04 or 85Y10, then the transceiver is a 403 -
470MHz band split. If the power amplifier shield marking is 25U05
or 85Y11, then the transceiver is a 450 - 520MHz band split.
• The "C" kits can be identified by the circuit board number
4221J07 or 4221J37 visible on side 2 of the board, located along
the circuit board edge just next to crystal filter FL1. All future UHF
transceiver boards will be in the "4221J" series.
Anytime a controller board or transceiver board is replaced in a radio,
it will be necessary to perform the RSS transmit VCO crossover
alignment, and check the transmit VCO crossover frequency. The RSS
screen for this alignment will show a "current value" box
with a frequency already assigned, placed inside the box. When
performing transmit VCO crossover alignment, determine the UHF
transceiver band split, and then check the transceiver circuit board
number. In a UHF radio (403 - 470MHz range):
• If the board number is any "4221J" series number, other than
4221J01 thru 4221J06 or 4221J36, the transmit VCO crossover
frequency in the "current value" box should be 449.500MHz. If it
is not, change it to 449.500MHz.
• If the board number is 4221J01 thru 4221J06, 4221J36, or any
other number not in the 4221J series, the transmit VCO crossover
frequency in the "current value" box should be 438.025MHz. If it
is not, change it to 438.025MHz.
VCO varactors (CR201, 203, 207, 208, and 209) in "C" and later kits
are not interchangeable with VCO varactors in earlier kits; Motorola
parts and part numbers are different. When replacing a VCO varactor,
identify the UHF transceiver band split and the transceiver circuit
board number, and then order replacement parts from the applicable
parts list.
UHF transceiver board (450 - 520MHz band split) NUE7232 and
NUE7241 ("C" and later) kits include new VCO varactors, and are
factory aligned with a new transmit VCO crossover frequency of
495.375MHz.
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