Motorola Two Way Portable Radio Ht1000 Jt1000 Mt2000 Mts2000 Mtx Series 6881200c75 B Manual

39 are raised enough to see plating under them, 
then the flex is not fully seated.
5. Reinstall the rubber controls top seal on the control top.
NOTE:Two tabs are provided in the emergency button 
area to help hold the seal in place.
Front Cover Assembly to 
Chassis1. Install the contoured O-ring/antenna bushing seal around the 
antenna and in the groove provided (see Figure 15).
2. Orient the front cover assembly with the chassis, and insert the 
front cover/display flex connector into the locking...

40cover clip and the chassis.With the top of the 
chassis fully seated, lower the bottom of the 
chassis and press it into the front cover 
assembly until it snaps into place.
4. Check the emergency button again. If it is cocked to one side, 
repositioning it will be necessary.
Knobs, Antenna, and 
Battery1. Reinstall the switch knobs and antenna; the shorter knob with the 
volume on/off switch, the taller knob with the channel selector 
switch.
2. Reinstall the battery. 

41
Maintenance
7
IntroductionThis section of the manual describes preventive maintenance, safe 
handling of CMOS devices, and repair procedures and techniques. 
Each of these topics provides information vital to the successful 
operation and maintenance of your radio.
Preventive 
MaintenanceIn order to avoid operating outside the limits set by the FCC, it is 
recommended that the reference oscillator of the HT 1000, JT 1000, 
MT 2000, MTS 2000, and MTX radio be aligned every time the radio is...

42
Alcohol is a high-wetting liquid and can carry contamination into 
unwanted places if an excessive quantity is used. Make sure that 
controls or tunable components are not soaked with the liquid. Do not 
use high-pressure air to hasten the drying process, since this could 
cause the liquid to puddle and collect in unwanted places.
Upon completion of the cleaning process, use a soft, absorbent, lintless 
cloth to dry the area. Do not brush or apply any isopropyl alcohol to 
the frame, front cover, or...

43 work for shorts due to solder bridges. When removing modules with 
metal enclosures, be sure to desolder the enclosure ground tabs as well 
as the module pins.
Flexible CircuitsThe flexible circuits are made from a different material than the rigid 
boards, and different techniques must be used when soldering. 
Excessive prolonged heat on the flexible circuit can damage the 
material. Avoid excessive heat and excessive bending. For parts 
replacement, use the ST-1087 Temperature-Controlled Solder...

44
Jumper Flex (on radios 
shipped prior to 7/94)Jumper flexes are not available. They are replaced with connectors as 
described in paragraph “a” of this section. If the jumper flex needs to 
be replaced, order Interconnect Kit REX4350A. The retrofit kit includes 
all of the parts required and detailed instructions on the removal of the 
old jumper flex, and the installation of the new connector 
arrangement.
RF Switch (S101):Refer to the applicable exploded view and to your radios RF board 
(antenna...

45 plastic switch housing to ensure that it has not warped due to 
overheating.
2. While holding the RF switch bracket firmly against the RF board:
VHF and UHF radios - solder the two leads of the housing to the 
solder pads on the RF board.
800MHZ and 900MHz radios - bend the two tabs around the side 
of the RF board as close to the board edge as possible to hold the 
bracket down tightly.
3. Insert the new RF switch spring and RF switch piston into the RF 
switch assembly. The contacts of the piston...

46During all repair procedures, heating neighboring components can be 
minimized by:
using upper heat only.
using the correct size heat-focus head, approximately the same size 
as the carrier being replaced.
keeping the heat focus head approximately 1/8”-1/4” (0.3cm-
0.6cm) above the printed circuit board when removing or 
replacing the device.
To  R e m o v e  a  P B G A  C o m p o n e n t ,  select the R-1319 Rework Station and the appropriate heat- focus head 
(approximately the same size as the...

47 To Replace an PBGA compo-
nent, the solder pads on the board must first be cleaned of all solder to 
ensure alignment of the new chip carrier. Prepare the site by using 
solder wick and a soldering iron to remove all solder from the solder 
pads on the circuit board. If a power desoldering tool is available, it can 
be used instead of the solder wick. Clean the solder pads with alcohol 
and a small brush. Dry and inspect. Ensure that all solder is removed.
Once the preparation is complete, place the...

48Once the part is off, turn off the heat, grab the part with a pair of 
tweezers, and turn off the vacuum pump. Prepare the circuit board for 
the new component by applying solder paste flux to the solder pads. 
Position the circuit board under the heat-focus head, lower the head 
to approximately 1/8”-1/4” (0.3cm-0.6cm) above the board, and turn 
on the heat. When the solder left behind on the pads reflows, turn off 
the heat and raise the heat-focus head. Remove the circuit board from 
the holder and...