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 connector of 
the controller board (refer back to Figure 6). Secure the 
connection. View the flex connection at a slight angle from the 
top of the radio and ensure that the flex connector is fully seated 
into the locking connector as illustrated in Figure 7.
3. Check to make sure that the O-ring is in place, and slide the 
chassis (control top first) into the front cover assembly. Check to 
ensure that the orange emergency button seal slides into position 
freely.
NOTE:When performing the next part of this step, 
pay particular attention to the O-ring near the 
bottom of the radio to ensure that it does not 
raise up and get pinched between the front 
MAEPF-22579-A
Flex Not Fully Seated
in ConnectorFlex Fully Seated
in Connector
Misaligned
Plating
Reliefs
Figure 14  Seating the Flex
Figure 15  Installing the O-Ring/Antenna Bushing Seal
Contoured O-ring/
Antenna Bushing Seal
MAEPF-27018-O
Contoured O-ring/
Antenna Bushing Seal
Unit with 
early Front Shield Unit with 
latest Front Shield  
						

							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 
disassembled, or once a year, whichever comes first. Periodic visual 
inspection and cleaning are also recommended.
InspectionCheck that the external surfaces of the radio are clean, and that all 
external controls and switches are functional. A detailed inspection of 
the interior electronic circuitry is not needed or desired.
CleaningThe following procedures describe the recommended cleaning agents 
and the methods to be used when cleaning the external and internal 
surfaces of the radio. External surfaces include the front cover, chassis 
(rear cover), and battery case. These surfaces should be cleaned 
whenever a periodic visual inspection reveals the presence of smudges, 
grease, and/or grime. Internal surfaces should be cleaned only when 
the radio is disassembled for servicing or repair.
The only recommended agent for cleaning the external radio surfaces is a 
0.5% solution of a mild dishwashing detergent, such as JOY®, in water. 
The only factory recommended liquid for cleaning the printed circuit 
boards and their components is isopropyl alcohol (70% by volume).
Cleaning External Plastic 
SurfacesThe detergent-water solution should be applied sparingly with a stiff, 
non-metallic, short-bristled brush to work all loose dirt away from the 
radio. A soft, absorbent, lintless cloth or tissue should be used to 
remove the solution and dry the radio. Make sure that no water 
remains entrapped near the connectors, cracks, or crevices.
Cleaning Circuit Boards and 
ComponentsIsopropyl alcohol may be applied with a stiff, non-metallic, short-
bristled brush to dislodge embedded or caked materials located in 
hard-to-reach areas. The brush stroke should direct the dislodged 
material out and away from the inside of the radio.
!
C a u t i o n
The effects of certain chemicals and their vapors 
can have harmful results on certain plastics. 
Aerosol sprays, tuner cleaners, and other 
chemicals should be avoided. 
						

							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 back cover.
NOTE:Always use a fresh supply of alcohol and a 
clean container to prevent contamination by 
dissolved material (from previous usage).
Safe Handling of 
CMOS DevicesComplementary metal-oxide semiconductor (CMOS) devices are used 
in this family of radios. While the benefits of CMOS are many, their 
characteristics make them susceptible to damage by electrostatic or 
high voltage charges. Damage can be latent, resulting in failures 
occurring weeks or months later. Therefore, you must take special 
precautions to prevent device damage during disassembly, 
troubleshooting, and repair. Handling precautions are mandatory for 
CMOS circuits, and are especially important in low humidity 
conditions. DO NOT attempt to disassemble the radio without first 
referring to the CMOS CAUTION paragraph in the Disassembly and 
Reassembly section of the manual.
Repair Procedures 
and TechniquesRefer to the Disassembly and Reassembly section of the manual for 
pertinent information prior to replacing and substituting parts.
General
Parts Replacement and 
SubstitutionSpecial care should be taken to be as certain as possible that a 
suspected component is actually the one at fault. This special care will 
eliminate unnecessary unsoldering and removal of parts, which could 
damage or weaken other components or the printed circuit board 
itself.
When damaged parts are replaced, identical parts should be used. If 
the identical replacement component is not locally available, check 
the parts list for the proper Motorola part number and order the 
component from the nearest Motorola Communications Parts office 
listed in the “Replacement Parts Ordering” section of this manual.
Rigid Circuit BoardsThis family of radios uses bonded, multi-layer, printed circuit boards. 
Since the inner layers are not accessible, some special considerations 
are required when soldering and unsoldering components. The 
printed-through holes may interconnect multiple layers of the printed 
circuit. Therefore, care should be exercised to avoid pulling the plated 
circuit out of the hole.
When soldering near the module socket pins, use care to avoid 
accidentally getting solder in the socket. Also, be careful not to form 
solder bridges between the module socket pins. Closely examine your  
						

							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 Station 
with a 600 or 700 degree tip, and use small diameter solder such as ST-
633. The smaller size solder will melt faster and require less heat being 
applied to the circuit.
To replace a component on a flexible circuit, grasp the edge of the 
flexible circuit with seizers (hemostats) near the part to be removed, 
and pull gently. Apply the tip of the soldering iron to the component 
connections while pulling with the seizers. Do not attempt to puddle 
out components. Prolonged application of heat may damage the 
flexible circuit.
SpecificDuring 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” above the printed 
circuit board when removing or replacing the device.
Strip Connector (P301/
P704)On the latest version HT 1000, JT 1000, MT 2000, MTS 2000, and MTX 
series radios, a strip connector, two female connectors and a strain 
relief electrically connect the RF board with the controller board. On 
earlier versions of these radios, the RF board and controller board were 
connected using a jumper flex that soldered directly to the circuit 
board solder pads.
An interconnect kit, REX4350A, is available to retrofit earlier version 
jumper-flex radios with the later version strip connector parts. The 
REX4350A kit includes the following items: 
CONNECTOR, Female (J301) 0905461X01
CONNECTOR, Female (J704) 0905461X01
CONNECTOR, Male (P301/P704) 0905461X01
STRAIN RELIEF 4205507X01
INSTRUCTIONS 6880309F14
!
C a u t i o n
If neighboring PBGA components are heated 
above 365 degrees F. (185 degrees C.), they will 
suffer die-bond delamination and possible 
“popcorn” failure. 
						

							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 contact area) to locate the RF switch components. 
NOTE:The RF switch spring and the RF switch piston 
must be ordered separately.
To Remove the RF Switch:1. On VHF and UHF radios, unsolder the two tabs of the RF switch 
bracket that secure the RF switch to the RF board. On 800MHz and 
900MHz radios, use a #2 slotted screwdriver to straighten the two 
tabs of the RF switch bracket that wrap around the RF board. Use 
your forefinger to hold the RF switch bracket to the RF board while 
straightening the tabs to avoid lifting the solder tabs on the 
opposite end of the RF switch bracket.
2. Refer to Figure 16 and use a small heat-focus head to distribute 
heat over the area occupied by the three solder tabs until the 
solder softens.
3. Carefully lift the RF switch assembly away from the rf board. 
Notice that the RF switch circuit board remains attached (soldered) 
to the RF board.
4. Using the same heat-focus head as in steps (2) and (3), unsolder 
the RF switch circuit board, and remove it from the RF board using 
forceps.
5. In the RF switch circuit board area, reflow all the solder pad areas 
on the main RF board such that similarly shaped pads have 
uniform solder heights. Add or remove solder as required. Clean 
the RF board thoroughly. Then swab on a minimum amount of 
flux to each of the solder pads.
To  R e p l a c e  t h e  R F  S w i t c h :1. Place the RF switch assembly on the RF main board and gently 
heat. Visually inspect to make sure no flux migrated onto the gold 
plated areas of the RF switch board. The guide pins should provide 
self alignment between the two circuit boards. Visually inspect the 
3 Solder
Tabs
Figure 16  Solder Tabs 
						

							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 should be facing the 
gold-plated pads of the RF switch board. Once the spring and 
piston are inserted into the RF switch, they will be retained by the 
switch.
Chip ComponentsUse either the RLN-4062 Hot-Air Repair Station or the Motorola 
0180381B45 Repair Station for chip component replacement. When 
using the 0180381B45 Repair Station, select the TJ-65 mini-thermojet 
hand piece. On either unit, adjust the temperature control to 700 
degrees F. (370 degrees C), and adjust the airflow to a minimum 
setting. Airflow can vary due to component density.
1. To remove a chip component, select a hot- air hand piece and 
position the nozzle of the hand piece approximately 1/8” (0.3cm) 
above the component to be removed. Begin applying the hot air. 
Once the solder reflows, remove the component using a pair of 
tweezers. Using solder wick and a soldering iron or a power 
desoldering station, remove the excess solder from the pads.
2. To replace a chip component using a soldering iron, select the 
appropriate micro-tipped soldering iron and apply fresh solder to 
one of the solder pads. Using a pair of tweezers, position the new 
chip component in place while heating the fresh solder. Once 
solder wicks onto the new component, remove the heat from the 
solder. Heat the remaining pad with the soldering iron and apply 
solder until it wicks to the component. If necessary, touch up the 
first side. All solder joints should be smooth and shiny.
3. To replace a chip component using hot air, select the hot-air hand 
piece and reflow the solder on the solder pads to smooth it. Apply 
a drop of solder paste flux to each pad. Using a pair of tweezers, 
position the new component in place. Position the hot-air hand 
piece approximately 1/8” (0.3cm) above the component and begin 
applying heat. Once the solder wicks to the component, remove 
the heat and inspect the repair. All joints should be smooth and 
shiny.
Plastic-Ball Grid-Array 
(PBGA), Over-Molded Pad-
Array Carrier (OMPAC), and 
Glob Top ComponentsThe term Plastic-Ball Grid-Array (PBGA) will be used to describe most 
of this products type of modules. PBGA modules may be the 
construction of an Over-Molded Pad-Array Carrier (OMPAC) 
component or “Glob Top” component. A U204 synthesizer 
component in one radio may be an OMPAC and the same U204 
synthesizer in another radio may be a Glob Top. The two components 
look a little different, but are electrically the same and are 
interchangeable. 
						

							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 PBGA. Attach the heat-focus head 
to the chimney heater. Adjust the temperature control to 
approximately 415 degrees F (215 degrees C); 445 degrees F (230 
degrees C) maximum. Apply the solder paste flux around the edge of 
the PBGA. Place the circuit board in the circuit board holder, and 
position the PBGA component under the heat-focus head. Lower the 
vacuum tip and attach it to the PBGA component by turning on the 
vacuum pump. Lower the heat-focus head until it is approximately 1/
8”-1/4” (0.3cm-0.6cm) above the carrier. Turn on the heater and wait 
until the PBGA component lifts off the circuit board. Once the part is 
off, grab it with a pair of tweezers and turn off the vacuum pump. 
Remove the circuit board from the R-1319’s circuit board holder.
!
C a u t i o n
If neighboring PBGA components are heated 
above 365 degrees F. (185 degrees C.), they will 
suffer die-bond delamination and possible 
“popcorn” failure. To prevent this delamination 
problem, circuit boards to be repaired must be 
baked in an oven for eight hours at 260 degrees F. 
(125 degrees C.) prior to solder repairs.
!
C a u t i o n
All pad-array carriers in these radios, except for 
the IF IC (U3), are PBGA components. Prior to use, 
all PBGA components must be kept in the sealed 
bag (with moisture-indicator card) as supplied by 
the Motorola Parts Department. Once the sealed 
bag is opened and/or the PBGA component 
subjected to ambient humidity (for an unknown 
amount of time or for more than 96 hours) then 
that PBGA component must be baked in an oven 
for at least eight hours at 260 degrees F. (125 
degrees C.) 
						

							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 circuit board back in the 
circuit board holder. Add solder paste flux in the trench of the flux 
block and spread it using a one-inch putty knife. Flux the PBGA 
component by placing it in the trench of the flux block. Once the flux 
is applied, place the PBGA component on the circuit board, making 
certain that it is oriented correctly on the board. Position the heat-
focus head over the PBGA component and lower it to approximately 
1/8”-1/4” (0.3cm-0.6cm) over the carrier. Using the same heat setting 
used to remove the PBGA component, turn on the heater and wait for 
the carrier to reflow (heating and reflow should take longer than 60 
seconds).Watch the PBGA component reflow and note that when a 
proper reflow has taken place, the PBGA component will drop (usually 
one side, then the other). The end result is that both sides have 
reflowed, and the PBGA component is sitting parallel to the circuit 
board.
Once the carrier reflows, raise the heat-focus head and wait 
approximately one minute for the part to cool. Remove the circuit 
board and inspect the repair. No cleaning should be necessary.
Thin Small Outline Package 
(TSOP) Components
Removing and Replacing a TSOP 
Component: will be done with the R-1319, using the same procedure used to 
remove and replace an PBGA component.
Place the circuit board in the circuit board holder. Select the proper 
heat focus head and attach it to the heater chimney. Position the TSOP 
component under the heat-focus head. Lower the vacuum tip and 
attach it to the component by turning on the vacuum pump. Lower 
the focus head until it is approximately 1/8”-1/4” (0.3cm-0.6cm) 
above the component. Turn on the heater and wait until the TSOP lifts 
off the circuit board.
!
C a u t i o n
The application of heat to the PBGA device, 
beginning at ambient air temperature and 
ending with the PBGA component lifting from 
the circuit board, should take longer than 60 
seconds. If the PBGA component lifts from the 
circuit board earlier than 60 seconds:
check the temperature control setting on 
the rework station, and if OK 
lift the heat-focus head an additional 1/8” 
from nominal setting, and
check the circuit board plating for possible 
damage. 
						

							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 inspect the pads to ensure that the solder has flattened 
out and that there are no solder shorts. Clean the area with alcohol 
and a small brush.
Once the preparation is complete, place the circuit board back in the 
circuit board holder. Add solder paste flux to the solder pads and place 
the new component on the circuit board. Position the heat-focus head 
over the component and lower it to approximately 1/8”-1/4” (0.3cm-
0.6cm) above the carrier. Turn on the heater and wait for the 
component to reflow.
Once the component reflows, raise the heat-focus head and wait 
approximately one minute for the part to cool. Remove the circuit 
board and inspect the repair. No cleaning should be necessary.
Shields
Removing and Replacing the 
Shields:will be done with the R-1319, using the same procedure used to 
remove and replace TSOP and PBGA components.
Place the circuit board in the circuit board holder. Select the proper 
heat focus head and attach it to the heater chimney. Add solder paste 
flux around the base of the shield. Position the shield under the heat-
focus head. Lower the vacuum tip and attach it to the shield by 
turning on the vacuum pump. Lower the focus head until it is 
approximately 1/8”-1/4” (0.3cm-0.6cm) above the shield. Turn on the 
heater and wait until the shield lifts off the circuit board. Once the 
shield is off, turn off the heat, grab the part with a pair of tweezers, and 
turn off the vacuum pump. Remove the circuit board from the circuit 
board holder.
To replace the shield, add solder to the shield if necessary, using a 
micro-tipped soldering iron. Next, rub the soldering iron tip along the 
edge of the shield to smooth out any excess solder. Use solder wick and 
a soldering iron to remove excess solder from the solder pads on the 
circuit board. Place the circuit board back in the circuit board holder. 
Place the shield on the circuit board using a pair of tweezers. Position 
the heat-focus head over the shield and lower it to approximately 1/
8”-1/4” (0.3cm-0.6cm) above the shield. Turn on the heater and wait 
for the solder to reflow.
Once complete, turn off the heat, raise the heat-focus head, and wait 
approximately one minute for the part to cool. Remove the circuit 
board and inspect the repair. No cleaning should be necessary.
RF PA (U105)The procedure for removing and replacing the RF PA is very similar to 
the procedure for removing and replacing an PBGA or a TSOP 
component. But because the device is large, extra heating time is 
required to flow the pads. And as a result, neighboring components 
(especially those on the opposite side of the circuit board) will heat,