Motorola Two Way Portable Radio Ht750 Ht1250 Mtx850 Mtx1250 Mtx8250 Mtx9250 Basic 68p80906z54 D Manual

Maintenance3-11
Figure 3-8: Lock Retainer Catches to the Radio’s Body
3.7.5 Chassis Assembly Reassembly
1. Slide on the ground contact (if it was removed) on the top corner boss of the chassis. 
2. Replace the O-ring. The tabs on the O-ring should reach into the chassis and point down.
3. Stretch the O-ring to place it into the retaining pocket at the bottom end of the chassis.
4. Ensure that the antenna nut insulator is correctly replaced by pushing it all the way to the top of 
the antenna nut.
5....

3-12Maintenance
8. Reassemble the knobs, dust cover, antenna, and battery.
Figure 3-9: Fastening the Chassis 
3.7.7 DTMF Retrofit Kit Procedure (Optional Upgrade Procedure)
If you are performing an upgrade from a basic model to a DTMF model, replace the existing front 
cover kit with kit number HLN9984 and follow the reassembly steps to reassemble the upgraded 
radio. (See paragraph 3.7 for details about reassembly.) 
To activate the retrofit using the radio software, follow these steps:
1. Start the...

Maintenance3-13
3.7.8 Option Board Installation
1. With the keypad retainer removed the keypad backer board can be removed without the use of 
tools.
2. Remove the jumper flex from the connector on the keypad board. Notice the orientation of the flex 
to the connector. Arrows on the jumper flex point to the correct way of inserting the flex into the 
connector.
3. Discard the keypad backer board.
4. The “breakaway” tab at the top of all option boards contains an extra row of keys and is used to...

3-14Maintenance
Notes
. 

3-29
3.8.15 HT1550•XLS Exploded ViewFigure 3-19: HT1550•XLS Exploded View
1
2
3
4
5
6
7
8
910
11
121314
15
1617
18
19
20
21
22
2324
2526
2728
29
30
3132
33
3435
3637
384041
42
43
44 39 

3-303.8.16 HT1550•XLS Exploded View Parts List
Table 3-8.  HT1550•XLS Parts List
Item
Motorola Part 
Number
Description
1 See Section 7 in 
manualAntenna
2 3280529Z01 Knob, Volume
3 3280530Z01 Knob, Frequency
4 1380525Z03 Escutcheon, Top (Dotted)
5 3380644Z01 Escutcheon, Adhesive
6 3280533Z01 Seal, Control Top
7 6180527Z01 Litepipe, Tx
8 HKLN4011A Nameplate, HT1550•XLS
9 1586059A01 Dust Cover, Univ Conn
10 1386058A01 Escutcheon, Univ Flex
11 1580666Z02 Front Cover DTMF
12 Not Field...

Service Aids3-35
3.9 Service Aids
Table 3-11 lists service aids recommended for working on the HT750/HT1250/HT1250•LS/
HT1250•LS+/HT1550•XLS/MTX850/MTX950/MTX850•LS/MTX8250/MTX9250/MTX8250•LS radios.
Table 3-11:Service Aids NOTE: While all of these items are available from Motorola, most are standard shop 
equipment items, and any equivalent item capable of the same performance may be 
substituted for the item listed.
Motorola 
Part No.Description Application
RLN4460Portable Test SetEnables connection to...

3-36Test Equipment
3.10 Test Equipment
Table 3-12 lists test equipment required to service the HT750/HT1250/HT1250•LS/HT1250•LS+/
HT1550•XLS/MTX850/MTX950/MTX850•LS/MTX8250/MTX9250/MTX8250•LS radios.
Table 3-12:Recommended Test Equipment
Motorola Part 
No.Description Characteristics Application
R2000, R2600
R2400, or R2001 
with trunking 
optionService MonitorThis monitor will 
substitute for items 
listed below with an 
asterisk *Frequency/deviation meter and sig-
nal generator for wide-range trouble-...

Configuring and Wiring the Programming/Test Cable 3-37
3.11 Configuring and Wiring the Programming/Test Cable
Figure 3-22: Programming/Test Cable AARKN4074
Figure 3-23: Pin Configuration of the Cable Side Connector
Block 

3-38 Configuring and Wiring the Programming/Test Cable
Figure 3-24:  Programming/Test Cable Schematic
1
2
5
7
8
9
16
18
19
20
21
22
25 15AUDIO -
AUDIO +
MIC AUDIO
GND
VOL CTRL
DISC
PTT
OPT SEL INT/EXT
BOOT CTRL
1
4
15
25 11GND
BIAS
BUS +
BOOT CTRL BUS -   1
  2
  3
  4
  5
  6
  8
  9
10
11
12
13   7 EXT SPKR +
  EXT SPKR -
 OPTION B+
 EXT MIC
OPT SEL 2
  OPT SEL 1
 RX DATA
TX DATA
RSSI
XMIT/RX AUDIO
BOOT CTRL
N/C  GND
P2
TO RADIO
TEST SET
RLN4460 P1
TO RADIO
UNIVERSAL
CONNECTOR
J1
TO RIB
RLN4008...