Icom Ic-910h Vhf/Uhf All Mode Tranciever Service Manual

SERVICE
MANUAL
VHF/UHF ALL MODE TRANSCEIVER
i910H 

INTRODUCTION
This service manual describes the latest service information
for the IC-910HVHF/UHF ALL MODE TRANSCEIVER at the
time of publication.
VERSION No.
#02
#04
#06
#07VERSION
Europe
Australia
U.S.A.
KoreaSYMBOL
EUR
AUS
USA-1
KOR
To upgrade quality, any electrical or mechanical parts and
internal circuits are subject to change without notice or
obligation.
DANGER
NEVERconnect the transceiver to an AC outlet or to a DC
power supply that uses more than 16 V.  This will ruin the
transceiver.
DO...

SECTION 1 SPECIFICATIONS
SECTION 2 INSIDE VIEWS
2 - 1 IC-910H  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1
2 - 2 UX-910 (OPTIONAL UNIT)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3
SECTION 3 DISASSEMBLY AND OPTION INSTRUCTIONS
SECTION 4 CIRCUIT DESCRIPTION
SECTION 5 ADJUSTMENT PROCEDURES
SECTION 6 PARTS LIST
SECTION 7...

SECTION 1 SPECIFICATIONS
1 - 1
GENERAL
• Frequency coverage :(Unit: MHz)
*
1Optional UX-910 is installed.
*2Guaranteed range is 144.0–148.0 MHz.
*3Guaranteed range is 430.0–450.0 MHz.
*4Guaranteed range is 1240.0–1300.0 MHz.
• Mode : USB, LSB, CW, FM, FM-N*
*Not available in 1200 MHz band
• No. of memory Ch. : 212 (99 regular, 6 scan edges, 1 calls for each band) plus 10 satellite memories)
• Antenna connector : SO-239 (50Ω; VHF)
Type-N (50Ω; UHF)
• Usable temp. range : –10˚C to +60˚C; +14˚F to +140˚F
•...

RECEIVER
•Receive system : 
VHF SSB, CW
Single conversion superheterodyne
FMDouble conversion superheterodyne
UHF SSB, CWDouble conversion superheterodyne
FM Triple conversion superheterodyne
•Intermediate frequencies :
(Unit: MHz)
•Sensitivity : SSB, CW (10 dB S/N)Less than 0.11 µV
FM 
(12 dB SINAD)Less than 0.18 µV 
•Squelch sensitivity : SSB, CW Less than 1.0 µV
(threshold)FM Less than 0.18 µV
•Selectivity : SSB, CW More than 2.3 kHz/–6 dB
Less than 4.2 kHz/–60 dB*
FM  More than 15.0 kHz/–6 dB
Less...

2 - 1
SECTION 2 INSIDE VIEWS
2-1 IC-910H
• MAIN AND PLL UNITS
DDS IC
(IC701: SC-1287) DDS gate array
(IC131: SC-1246A) DDS gate array
(IC331: SC-1246A) PLL unit
144 MHz band VCO circuit 430 MHz band VCO circuit
Reference oscillator
(X512: CR-452 30.2 MHz) Driver IC
(IC1: BU4094BCF) DDS IC
(IC601: SC-1287)
AF power amplifier
(IC1852: LA4445) MAIN unit * Located under side of the point
FM IF IC
(IC951: TA31136FN)
D/A converter
(IC1521: M62352GP)
Analog master IC*
(IC1701: mPC5023-077)
FM IF IC
(IC401:...

2 - 2
• PA UNIT
TX balanced mixer
 Q501, Q502: 2SK302
 D502: 1SV286 RX balanced mixer
(Q511, Q512: 2SK1740) Pre-amplifier
(Q507: 3SK177)
145 MHz power amplifier
(Q651, Q652: 2SC5152) TX/RX switching relay
(RL700: AE5349)
Varistor-A boardVaristor-C board
440 MHz power amplifier
(Q151, Q152: 2SC3102)
TX balanced mixer*
(Q1, Q2: 2SK302) Pre-amplifier
(Q260: 3SK177)
RX balanced mixer
(Q220, Q221: 2SC3356)
DRV boardDrive amplifier
(Q131: SRFJ7044)
* Located under side of the pointVaristor-B board
TX double...

2 - 3
2-2 UX-910 (OPTIONAL UNIT)
• TOP VIEW
• BOTTOM VIEW
Power module IC
(IC21: M57762-02)
1st LO VCO circuit PLL IC
(IC501: TB31242)
DDS IC
(IC661: SC-1246A)RF pre-amplifier
(Q281: NE34018) Power supply circuit
for AG-1200
 Q72: DTC144EU
 Q73, Q74: 2SC2712
RF amplifier
(Q271: 2SC5454)
YGR amplifier
(IC141: mPC1878G)TX 1st mixer
(IC131: mPC8163TB)
RX 1st mixer
(IC241: mPC2721)
TX 1st IF amplifier
(IC111: mPC2709)
RX 2nd mixer
(Q221: 3SK166)
TX 2nd mixer
(D82: HSB88WS)
2nd LO VCO circuit
Power supply...

SECTION 3 DISASSEMBLY AND OPTION INSTRUCTIONS
• Opening the transceiver’s case
Follow the case and cover opening procedures
shown here when you want to install an optional unit
or adjust the internal units, etc.
qRemove the 5 screws from the top of the trans-
ceiver and  4 screws from the sides, then lift up the
top cover.
wTurn the transceiver upside down.
eRemove 5 screws from the bottom of the trans-
ceiver, then lift up the bottom cover.
CAUTION:DISCONNECT the DC power cable
from the transceiver...

• Opening the PA unit cover
qRemove the top cover as shown in the diagram on p. 3-
1.
wRemove 8 screws and grounding plate from the PA unit
cover.
eRemove fastening tape from the inside power cable.
grounding plate
• FL-132/FL-133 CW NARROW FILTER
qRemove the bottom cover as shown in the diagram on 
p. 3-1.
• Remove the UX-910 if you have installed it. (p. 3-1)
wDisconnect the connection cable connectors from J501
and J1051 on the MAIN unit.
eRemove 2 clips.
WARNING!
BE CAREFULnot to pinch your finger...