Motorola Astro Digital Spectra Digital Spectra Plus Basic 6881076c20 E Manual

							6881076C20-EFebruary 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures 8-3
11. Remove the circuit board assembly from the housing.
12. Remove the keypad [6] from the housing assembly [7].
8.2.2.2  Models W4, W5, and W7
NOTE:For the following procedure, refer to Chapter 11: Exploded Views and Parts Lists, beginning 
on 
page 11-3, for the exploded view and associated parts list applicable to the model being 
disassembled.
1. Unplug the microphone.
2. Remove the two front panel screws using a 2.5mm hex-key driver.
3. Disconnect the control cable on remote models.
4. Grasp the front panel firmly, and carefully unplug the control head assembly from the radio or 
remote control head back housing.
5. Lay the control head face down on a clean, flat surface, being careful not to scratch or mar 
the display.
6. Using a Torx T10 driver, remove the control head screws:
- Model W4: four screws [callouts 5-8], as shown in 
Figure 8-1.
The Model W4 has, in addition to the screws, four snap features [callouts 1-4], which are shown in 
Figure 8-1.
- Model W5 and Model W7: seven screws, as shown in 
Figure 8-2.
Figure 8-1.  Model W4 Rotary Control Head Assembly Screw and Snap Sequence
Figure 8-2.  Models W5 and W7 Pushbutton Control Head Assembly Screw Sequence
7158
3426
416
2
5 3
7 
						

							February 3, 20036881076C20-E
8-4Disassembly/Reassembly Procedures: Replacement Procedures
7. Carefully separate the printed circuit board, internal spacer, and elastomer keypad assembly 
from the front panel.
On rotary control head models, care must be taken not to damage the flex circuit when 
separating the printed circuit board from the front housing. Do not disturb the buttons in the 
front panel.
On rotary control head models, the flex circuit must also be unplugged.
8. On rotary control head models, desolder the XMIT and BUSY LED before removing the 
elastomer keypad.
9. Remove the elastomer keypad from the printed circuit board.
NOTE:Before you unsnap the PC board, notice that the board slips under a hook on the 
right and snaps on the left. This will facilitate assembly.
10. Remove the PC board from the internal spacer. The PC board snaps into and out of the 
spacer.
11. To reassemble, snap the PC board into the internal spacer. Before you press the elastomer 
keypad into the board, make sure that the conductive pads in the board and the elastomer 
keypad are clean and free of any foreign material.
12. On rotary control head models, solder the XMIT and Busy LEDs onto the PC board.
NOTE:On rotary control head models, the flex circuit must be connected to the PC board 
prior to attaching the PC board to the spacer.
13. Install the PC board internal spacer and elastomer keypad assembly into the front panel. 
Replace the screws and torque them to 6-8 in.-lbs.
14. For dash-mounted radios, plug the interconnect board into the radio, then plug in the control 
head assembly and fasten it with the two front panel screws (torqued to 4-6 in.-lbs).
OR
For remote-mount control heads, replace the front panel into the remote control head back 
housing, make sure the gasket is in place, then torque the screws to 4-6 in.-lbs. Replace any 
plugs and cables on the rear of the control head.
8.2.2.3  Model W9
NOTE:Before disassembling the W9 control head, note the location of the labeled bottom.
NOTE:Refer to 
Figure 11-4: “Model W9 Pushbutton Control Head Exploded View,” on page 11-5 and 
Table 11-4, “Model W9 Pushbutton Control Head Parts List,” on page 11-5 for the callout 
numbers in this section.
1. Using a Torx T15 driver, remove the two 30mm machine screws [29] from the back housing 
[31] of the control head.
2. Fold the front housing [41] over so that the front housing is face down and the back housing is 
on your working surface with the flex cable [18] attached.
Take care to avoid misalignment of connector pins. On dash mount 
radios, remove the radio top cover to allow visual inspection during 
connector alignment.
!
C a u t i o n 
						

							6881076C20-EFebruary 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures 8-5
3. Using a Torx T10 driver, remove the five 8mm tapping screws [17] from the Display Board Kit 
[37], the two 10mm captive screws [12] with the leaf assembly spring [11], and the two 16mm 
tapping screws [38] from the control PC board.
4. Remove the Command Board Kit [36] from the back housing and the Display Board Kit [37] 
from the front housing.
5. Remove the elastomer keypad [7], ON/OFF switch gasket [34], the “D” Connector Gasket 
[33], the solder side shield [16], and the component side shield [19] from the PC boards.
NOTE:Be careful to not bend the tabs on the shields when removing them and align them 
carefully when replacing the shields. When working with chips and SOT (small 
outline transistor) parts, use extreme caution when heating. Never reuse a chip or 
SOT part; always replace with the correct Motorola part.
6. Install the new PC board with the elastomer keypad, the ON/OFF switch gasket, the “D” 
Connector Gasket, the “D” Connector O-ring, the solder-side shield, and the component-side 
shield in the appropriate locations.
7. Reassemble the Command Board Kit [36] into the back housing [31], making sure that the 
power switch is in the proper location and replace the two tapping screws [38], torquing them 
to 6-8 in.-lbs.
8. Reassemble the Display Board Kit [37] into the front housing [41], making sure that the 
elastomer keypad [7] is in the proper location.
9. Replace the captive screws [12] and the leaf assembly spring [11] in the front housing, and 
torque them to 6-8 in.-lbs.
NOTE:Before assembling the leaf assembly spring, check that the insulator [10] on the 
board is present. Ensure that the leaf assembly spring and captive screws are 
aligned properly to prevent stripping the front housing screw bosses.
10. Close the assembly by replacing the front housing [41] and the two screws in the back 
housing [31]. Torque the screws to 6-8 in.-lbs.
8.2.3 Remote Back Housing Interface Board
8.2.3.1  Models W4, W5, and W7
1. Unplug the microphone.
2. Disconnect the control cable from the control head on remote models.
3. Remove the two front panel screws using a 2.5mm hex-key driver.
4. Grasp the front panel firmly, and carefully unplug the control head assembly from the radio or 
remote control head back housing.
5. Remove the two remote back housing interface attachment screws.
6. Remove the remote control head interface board from the remote control head back housing.
7. Attach the new interface PC board to the back housing with two screws torqued to 6-8 in.-lbs.
8. Reassemble the back housing to the front housing with two screws torqued to 4-6 in.-lbs.
Take care to avoid misalignment of connector pins.!
C a u t i o n 
						

							February 3, 20036881076C20-E
8-6Disassembly/Reassembly Procedures: Replacement Procedures
8.2.4 Remote Interconnect Board
8.2.4.1  Low-/Mid-Power Radios
1. Remove the two front panel screws using a 2.5mm hex key driver.
2. Grasp the front panel firmly, and carefully unplug it from the radio.
3. Remove the three screws that hold the remote interconnect board to the front panel using a 
Torx T10 driver.
4. Install the new remote interconnect board onto the front panel, and replace the screws. 
Torque the screws to 6-8 in.-lbs.
5. Reassemble the front panel into the radio and replace the screws.
6. Torque the screws to 4-6 in.-lbs.
8.2.4.2  High-Power Radios
1. Use a Torx T15 driver to remove the two screws in the radio top cover. Remove the radio top 
cover.
2. Remove the ribbon cable [38-conductor] from between the command board and the 
interconnect board by first disconnecting the cable at the command board side and then at 
the interconnect board.
3. Disengage the retaining wire on the back of the interconnect board at the chassis side.
4. Use the radio key to unlatch the radio handle and use a Torx T15 driver to remove the two 
interconnect board screws that are inside the handle.
5. Turn the radio upside down and use a Torx T15 driver to remove the four bottom-cover 
screws. Remove the bottom cover.
6. Remove the RF board shield and unplug the coaxial cable that comes up from the other side 
of the radio. Move the end of the coaxial cable out from behind the interconnect board.
7. Pull the retaining wire up into position so that the interconnect board can be slid back away 
from the front of the radio, and then up and out from the radio chassis.
8. Remove the rubber gasket from the front of the interconnect board by pulling it up and over 
the D-connectors.
9. Gently pry each of the arms on the interconnect board spacer so that the snap feature on the 
arms can be slid past the interconnect board.
10. Place the interconnect board spacer onto the new interconnect board, by making sure that 
each arm is aligned in the proper slot and snaps securely into place.
11. Replace the rubber gasket, retaining wire, coaxial cable, bottom cover (torque four screws to 
6-8 in.-lbs), and interconnect board screws (torque two screws to 10-12 in.-lbs).
12. Turn the radio top side up and re-insert the ribbon cable [38-conductor] by first connecting the 
command board side, and then the interconnect board side. This cable is connected to two 
38-pin connectors. The cable is keyed so that the cable fits only in the correct position.
Take care to avoid misalignment of connector pins. Remove the 
radio top cover to allow visual inspection during connector alignment.!
C a u t i o n 
						

							6881076C20-EFebruary 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures 8-7
13. Fold the ribbon cable down flat. Replace the top cover and torque the two screws to 6-8 in.-
lbs. These screws are self-tapping and caution should be used so that the screws enter the 
previously cut threads.
8.2.5 Power Amplifier Board
8.2.5.1  Low-/Mid-Power Radios
1. Use a Torx T15 driver to remove the four screws from the PA cover, and then remove the 
cover and the PA shield.
2. Use a metric 3.0mm Allen wrench to remove the two Allen-head screws from the heatsink.
3. Carefully separate the PA assembly from the transceiver chassis.
NOTE:Before disconnecting, note which RF cable goes to the VCO (TX injection) and 
which goes to the RX front end. This will facilitate assembly.
4. Disconnect the large ribbon-cable connector from the command board, the small connector 
from the PA board, and two RF cables from their respective boards in the transceiver chassis.
5. Install the feed-through plat and grounding clip, making sure the RF cable is installed into the 
clip.
6. Install the receiver cable clip, making sure the cable is routed under the clip, and then fold the 
cables.
7. Connect the large ribbon-cable connector to the command board connector.
8. Connect the small connector to the PA.
9. Connect the RF cables to their respective boards in the transceiver chassis.
10. Be careful not to pinch the RF or ribbon cables, and position the PA assembly on the chassis.
11. Install the two Allen-head screws through the heatsink. Before tightening the mounting 
screws, check that the command board connector and RF connectors are in place. Torque 
the mounting screws to 14 in.-lbs.
12. Press the PA compartment shield and install the PA cover. Torque the screws to 10-12 in.-lbs.
13. Perform the radio alignment procedures and performance check procedures recommended 
in 
Table 8-1 on page 8-1.
8.2.5.2  High-Power Radios
1. Use a Torx T15 driver to remove the top cover by removing the two screws.
2. Disconnect the 12-conductor ribbon cable from the bottom of the power amplifier board.
3. Disconnect the red (A+) power cable from the bottom of the PA board.
4. Turn the radio upside down. Use a Torx T15 driver to remove the four bottom-cover screws. 
Remove the bottom cover.
5. Remove the PA shield.
6. Remove the harmonic filter cover.
7. Desolder the mini UHF cable connector from the PA board and the coax clip.
8. Disconnect the two coaxial cables from the board-mounted receptacles and the coax clip, 
noting where each cable goes for reassembly.
9. Use a Torx T15 driver to remove the two screws that anchor the PA board to the chassis.
10. Use a Torx T8 driver to remove the nine screws that anchor the components to the chassis.
11. Remove the PA board by carefully lifting the board out of the chassis while guiding it past the 
coaxial cables. 
						

							February 3, 20036881076C20-E
8-8Disassembly/Reassembly Procedures: Replacement Procedures
NOTE:Before disconnecting, note which RF cable goes to the VCO (TX injection) and 
which goes to the RX front end. This will facilitate assembly.
12. Apply a thin white coat of thermal compound (for example, Motorola part no. 11-83166A01) in 
the power transistor mounting locations of the chassis where the thermal compound was 
removed.
13. Locate the new PA board into the chassis cavity by feeding the short coaxial cable through 
the hole in the board and starting all the screws. After the ten PA screws are started, torque 
them to 8-10 in.-lbs.
14. Install the new strip outline emitters onto the new PA board by replacing the eight screws, and 
torque to 6-8 in.-lbs.
15. Solder the collector leads to the board.
16. Plug the coaxial cables into the mating receptacles on the board.
17. Solder the braided coaxial cable to the power amplifier board at the tip and at the braid.
18. Snap the harmonic-filter shield into place, and replace the power-amplifier shield over the 
power amplifier cavity. Make sure that the PA cover is firmly seated into the chassis cavity.
19. Replace the bottom cover, and torque the four bottom-cover screws to 6-8 in.-lbs.
20. Turn the radio top side up, and reconnect the 12-conductor ribbon cable to the bottom of the 
PA board.
21. Reconnect the red (A+) power lead to the bottom of the PA board.
22. Replace the radio top cover and torque the two screws to 6-8 in.-lbs.
8.2.5.3  800 MHz Radios
8.2.5.3.1  Back-End Removal
1. 20- and 35-watt radios only: Use a Torx T15 driver to remove four screws from the PA cover, 
and then remove the cover and lift the PA shield and the harmonic filter shield cover.
2. Use a metric 3.0-mm Allen wrench to remove the two Allen-head screws from the heatsink.
3. Carefully separate the PA assembly from the chassis.
NOTE:Before disconnecting, note which RF cable goes to the VCO and which goes to the 
RX front-end. This will facilitate assembly.
4. Disconnect the large ribbon cable connector from the command board, the small connectors 
from the PA board, and the two RF cables from their respective boards in the chassis.
8.2.5.3.2  PC Board Removal
NOTE:Before unfolding the RF cables, note how each is routed. This will facilitate assembly.
1. 15-watt radios: Insert a small, flat-blade screwdriver into the clip slot to deflect the snap 
holding one side of the clip to the shield and remove the two plastic clips that hold the RF 
cables to the shield. Unfold the RF cables and remove the PA compartment shield.
20- and 35-watt radios: Use a Torx T15 driver to remove two screws, and pull feed-through 
plate from the side of the PA assembly. Remove RF cable clip. Unfold the RF cables and 
push them through the slots in the PA compartment.
2. Unsolder the three leads for pass device Q9500.
3. Use a Torx T8 driver to remove two screws from the power shield.
4. 35-watt radios only: Remove two screws from the final device.
5. Disconnect the red power lead. 
						

							6881076C20-EFebruary 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures 8-9
6. Use a Torx T15 driver to remove the larger screws. (Five screws are used on 15-watt, six on 
the 20- and 35-watt.)
7. Carefully lift the PC board from the heatsink.
NOTE:Before unsoldering the RF cables, note which cable is attached to each connector 
on the board. This will facilitate assembly since the cables differ in length.
8. Unsolder the antenna coax cable attached to the bottom of the board.
9. Unsolder and remove the power module shield.
10. Unsolder the RF cables from the board.
8.2.5.3.3  PC Board Installation
1. Solder the RF cables to the board connectors.
2. Clean any old thermal compound from the mounting surfaces of the power transistor, power 
module, and (on 20- and 35-watt models) the final device.
If the power transistor insulator was not disturbed, it is not necessary to clean beneath it.
3. Apply a new, uniform coat of thermal compound (e.g., Motorola part no. 11-83166A01), which 
is thick enough to fill all small air voids, to the mounting surfaces.
NOTE:Do not use a thick coating of compound and do not allow any small bits of dirt or 
debris to get in the compound; such would degrade the thermal efficiency of the 
heatsink.
4. Solder the three leads of the Q9500 pass device.
5. Install the PC board, and then attach and tighten the screws (torque 8-10 in.-lbs.) in the 
sequence shown in 
Figure 8-3.
Figure 8-3.  PA Board Screw Fastening Sequence (800 MHz 15-Watt PA)
6. 20- and 35-watt radios only: Install the final device with two screws (torque 8-10 in.-lbs.). The 
properly oriented final device is shown in 
Figure 8-4.
12
34
5APPLY TERMINAL
COMPOUND HERE
PASS DEVICE
INSULATOR HERE 
						

							February 3, 20036881076C20-E
8-10Disassembly/Reassembly Procedures: Replacement Procedures
Figure 8-4.  PA Board Screw Fastening Sequence (800 MHz 20- and 35-Watt PA)
7. Place the power module shield over the power module.
8. Install the power module and shield with two compression washers and screws (torque 6-8 
in.-lbs.).
9. 20- and 35-watt radios only (
Figure 8-5): Solder the final device leads and five caps. Caps 
must be soldered flat to the board, and each cap surrounding the final device must be 
soldered as close to the device as possible.
Figure 8-5.  Installing the Final Device
10. Solder the power module leads, module shield, and transistor leads.
11. Install the red power lead.
8.2.5.3.4  Back-End Installation
1. 15-watt radios: Carefully position the RF cables through the slots in the PA shield and install 
the shield. Fold the RF cables under metal clips and install the two plastic clips.
20- and 35-watt radios: Push the RF cables through the slots in the PA compartment. Install 
the feed-through plate making sure the RF cable is routed under the plate. Install RF cable 
clip making sure the cable is routed under clip; fold the cables.
2. Connect the large ribbon cable connector to the command board connector.
3. Connect the small connector to the PA.
4. Connect the RF cables to their respective boards in the chassis.
5. Be careful not to pinch the RF or ribbon cables, and position the PA assembly on the chassis.
6. Install the two Allen-head screws through the heatsink. Before tightening the mounting 
screws, check that the command board connector and RF connectors are in place.
624
135
APPLY TERMINAL
COMPOUND HERE
PASS DEVICE
INSULATION HERE
POWER MODULE
U9850
D.C. CONN.Q9850
FINAL COLLECTOR
LEAD NOTCH 
						

							6881076C20-EFebruary 3, 2003
Disassembly/Reassembly Procedures: Replacement Procedures 8-11
7. Tighten the mounting screws (torque 8-10 in.-lbs.).
8. 20- and 35-watt radios only: Press the PA compartment shield, and install the PA cover.
8.2.6 VOCON (Vocoder/Controller) Board
NOTE:If you want to keep the information currently stored in the radio code plug, save its contents 
with the appropriate application software before you remove the original VOCON board. Refer 
to the Radio Service Software (RSS) user’s manual, or the Customer Programming Software 
online help.
1. Use a Torx T15 driver to remove the top cover by removing the four screws.
2. Remove the VOCON board shield.
3. Remove the board from the command board after reading the NOTES and CAUTIONS in this 
section.
4. Place the new board into the radio by aligning the pins and pressing the board firmly into 
place, and then replace the board shield.
5. Replace the radio top cover, and use four new screws (torque to 10-12 in.-lbs.) to secure the 
top cover. Ensure the screws are aligned with the holes.
NOTE:Replacement VOCON boards are preprogrammed to enable the radio to function 
only at test mode level. To restore the radio to complete operation, you must 
program the VOCON board via the radio service software or the Customer 
Programming Software.
6. Program the VOCON board as indicated in 
Table 8-1 on page 8-1. Programming procedures 
are found in 
Chapter 6: Radio Alignment Procedure of this manual.
8.2.7 Command Board
8.2.7.1  Low-/Mid-Power Radios
1. Remove the radio top cover.
2. Remove the PA assembly.
3. Remove the VOCON board according to previous instructions. See CAUTION notes in 
VOCON board replacement section.
4. Disconnect the PA connector and the control head connector.
5. Remove the heatsink clip from the power transistor on the command board.
6. Use a Torx T15 driver to remove six mounting screws.
To remove the VOCON board, gently pry the board up at the center 
of the connector end of the board. This will help prevent damage or 
bending of the connector pins.
Once installed, a replacement VOCON board may not be initialized 
a second time. Use the radio test modes to ensure that replacing the 
VOCON board will solve the problem before you initialize it.
!
C a u t i o n
!
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							February 3, 20036881076C20-E
8-12Disassembly/Reassembly Procedures: Replacement Procedures
7. Carefully lift the command board from the housing, making sure that the floating header is 
with the RF board.
8. To reassemble the command board, apply a thin coat of thermal compound (for example, 
Motorola part no. 11-83166A01) to the audio amplifier mounting surface.
NOTE:Do not use a thick coating of compound as it could degrade the thermal efficiency 
of the heatsink.
Prior to installing the command board, make sure the male-to-male command board 
header is fully seated in the RF board. 
9. Install the new command board, and clip the power devices to the chassis, being sure that the 
insulator is in place behind the devices.
10. Install new mounting screws (torque 8-10 in.-lbs.), starting with the screw holding down the 
audio amplifier. Ensure the screws are aligned with the holes.
11. Connect the VOCON board and option board.
12. Install the VOCON board shield.
13. Reconnect the two connectors.
14. Install the PA assembly, control head, and radio covers.
8.2.7.2  High-Power Radios
1. Use a Torx T15 driver to remove the two screws. Remove the top cover.
2. Disconnect and remove the 12-connector ribbon cable from the command board and the PA 
board.
3. Disconnect the 38-conductor ribbon cable from the command board.
4. Remove the heatsink clip from the three transistors in the corner of the board.
5. Remove the VOCON board shield.
6. Remove the VOCON board from the command board after reading the NOTES and 
CAUTIONS in the VOCON board section.
7. Use a Torx T15 driver to remove the six screws retaining the command board.
8. Gently work the command board out of the chassis cavity and then remove the foam piece 
from the crystal near the PA ribbon connector.
9. To reassemble the command board, apply a thin coat of thermal compound (for example, 
Motorola Part No. 11-83166A01) to the audio amplifier mounting surface.
NOTE:Do not use a thick coating of compound as it could degrade the thermal efficiency 
of the heatsink. Prior to installing the command board, make sure the male-to-male 
command board header is fully seated in the RF board.
10. Install the new command board into the chassis cavity.
11. Replace the foam piece.
12. Using six new screws, start all the screws, and then torque them to 8-10 in.-lbs. Ensure the 
screws are aligned with the holes.
13. Replace the heatsink.
14. Connect the 12-connector ribbon cable from the command board to the PA board.
15. Connect the 38-conductor ribbon cable to the command board.
16. Reassemble the VOCON board.