Midland 70-1526A User manual

441 DLAN D
LAND MOBILE RADIO
SERVICE MANUAL
MOBILE TRANSCEIVER
UHF BAND
[406 - 430 MHz, 450 - 470 MHz)
15-25 WATT
MANUAL NO.: 70-152600
09-1526-SM-4/91-2M

This manual section is designed to facilitate the set-up and service of the Midland 70-1526
transceivers. As necessary, service maual supplements will be published and distributed on the
following forms:
Manual Addition (MA) .For supplemental information useful in product service or
improvement. Printed on BLUE paper.
Change Notice (CN).For details about changes made during production by
model and serial number. Printed on YELLOW paper.
Manual Correction (MC).For correcting literature errors not related to production
changes. Printed on GREEN paper.
Technical Bulletin (TB) ....... For solutions to field problems and tips for performance
improvement. Printed on PINK paper.
Comments or suggestions concerning areas of manual improvement are welcome.
ii

TABLE OF CONTENTS
Manual Supplement Information....... .11
Table of Contents ...... lil
SECTION 1 GENERAL INFORMATION
Description...1-3
Specifications.....1-3
SECTION 2 PREPARATION
Pre-Installation Check.2-3
Complete Realignment. 2 - 3
SECTION 3 INSTALLATION
Installation ..3-3
SECTION 4 SERVICING
Component Replacement.......4-3
Eliminating Radio Interference ..... 4 - 7
Voltage Charts. . 4 - 1 1
Troubleshooting Charts ........ 4 -14
SECTION 5 CIRCUIT DESCRIPTIONS
RF Section .5-3
25-Watt PA Section...5-5
Logic Section.5-5
SECTION 6 DIAGRAMS
Block Diagram...6-3
Wiring Diagram .6-4
CX-103 Layout.....6-4
CX-104 Layout.... 6 - 4
TR-423 Layout — Bottom View ...6-5
TR-423 Layout — Top View .6-6
TR-423 Schematic...6-7
Component Layout. , 6 - 8
Diode Pinouts...... 6 - 9
Transistor Pinouts.......6-9
Exploded View. 6 - 1 0
SECTION 7 PARTS
Parts List....7-3
Replacement Parts Ordering ... 7 - 1 0

SECTION 1 — General Information
SECTION 2 — Preparation
SECTION 3 — installation
SECTION 4 — Servicing
SECTION 5 — Circuit Descriptions
SECTION 6 — Diagrams
SECTION 7 — Parts

GENERAL INFORMATION
70-1526
NOTES

_ GENERAL INFORMATION
70-1526
DESCRIPTION
The 70-1526 Midland 8-Channel Wide Band transceivers are programmable frequency-synthesized two-
way FM mobile radios that operate in the UHF frequency range. They are programmable for up to eight
channels.
The 70-1526 is designed to operate within either of two frequency ranges: 406—430 MHz (A-Band), or
450—470 MHz (B-Band). Transmit RF power is adjustable for 15—25 Watts.
SPECIFICATIONS
Refer to EIA-152-C, EIA/TIA-204-D, EIA-220-B, and DOC RSS-119 for standard of performance and method
of measurement.
GENERAL
OPERATING FREQUENCY RANGE:
A-Band: 406^430 MHz
B-Band: 450—470 MHz
CHANNEL SEPARATION: 24 MHz
CHANNEL SPACING: 25 kHz
CHANNEL STEPPING: 12.5 kHz/5 kHz optional
CHANNEL CAPACITY: Programmable for up to eight channels
POWER SUPPLY: 13.6 V DC negative to ground
CURRENT DRAIN:
Transmit (at 25 W): 10.0 A
Receive (@ rated audio): 2.0 A
Standby (std, varies with options): 400 mA
OPERATING TEMPERATURE: -30° C + 60° C
DIMENSIONS (H xWxD): 2x7x87/ 8 i n (50x 178x225mm)
WEIGHT: 2.5 kg

GENERAL INFORMATION
70-1526
TRANSMITTER
RF POWER OUTPUT (adjustable):
FREQUENCY STABILITY:
MODULATION (FOR 100% AT 1000 Hz):
BANDWIDTH:
SPURIOUS AND HARMONICS:
FM HUM AND NOISE:
AUDIO RESPONSE:
AUDIO DISTORTION (±3 kHz deviation):
OUTPUT IMPEDANCE:
15—25 W
±0.0005% (—30°C + 60° C)
16K0F3E ±5.0 kHz @ 25 kHz
24/20 MHz without retuning
-60 dB
-50 dB
per EIA and DOC specifications
Less than 3% @ 1 kHz
50 Q
RECEIVER
FREQUENCY STABILITY:
SENSITIVITY:
12 dB SINAD:
20 dB Quieting:
SELECTIVITY:
BANDWIDTH:
ACCEPTABLE RADIO FREQUENCY
DISPLACEMENT:
SPURIOUS REJECTION:
INTERMODULATION:
SQUELCH SENSITIVITY:
AUDIO OUTPUT:
Internal Speaker:
External Speaker:
±0.0005% (-30° C + 60° C)
0.30 fiV
0.5/fV
-75 dB @ ±25 kHz
24/20 MHz without retuning
±3.0 kHz @ 25 kHz
-80 dB
-75 dB
0.2/A/ maximum
2 W @ less than 3% distortion @ 8 Q
5W@ less than 3% distortion @ 3.2 Q
INPUT IMPEDANCE: 50 Q