Icom IC-910H service manual Transmitter Adjustments

5-5 TRANSMITTER ADJUSTMENTS

					MEASUREMENT				ADJUSTMENT
ADJUSTMENT		ADJUSTMENT CONDITION						VALUE	POINT
					UNIT	LOCATION			UNIT	ADJUST
PA UNIT	1	• Preset R131, R135, R150, R650 (PA unit) to max. counter clockwise.
PRESETTING		• Preset R3, R138, R503 (PA unit) to center position.
		• Preset C154, C659 (PA unit) to center position as illustration at right.
IDLING	1	• Display frequency:			PA	Connect an ammeter	At the point where the PA			R131
CURRENT		[EUR], [KOR]		145.0000 MHz		(3 A) between power	TX current increases
(for 144 M)		[USA-1], [AUS]		146.0000 MHz		supply and the IC-	0.5 A.
		• Mode	: CW			910H.

•Transmitting

2

• Transmitting

At the point where the

R135

TX

current increases

(R138)

1.0 A as step 1.

3

• Transmitting

At the point where the

R650

TX

current increases

0.5 A as step 2.

(for 430 M)

4

• Display frequency:

At the point where the

R150

[EUR], [KOR]

435.0000 MHz

TX

current increases

[USA-1], [AUS]

450.0000 MHz

1.0 A.

• Mode

: CW

• Transmitting

RF PEAK

1

• Display frequency: 440.0000 MHz

Rear

Connect

an

RF

Maximum output

PA

L1, L2

(for 430 M)

• Connect an SSG to P1 on the PA

panel

power meter to [UHF

power

unit via the JIG cable (A) and set as:

ANT] connector.

Frequency : 10.850 MHz

Level

: 18 mV* (–22 dBm)

Modulation : OFF

• Transmitting

2

• Set an SSG as:

C154

Level

: 0.79 µV* (–2 dBm)

• Transmitting

(for 144 M)

3

• Connect an SSG to P501 on the PA

Connect

an

RF

Refer page 5-16 software adjustment 6.

unit via the JIG cable (A) and set as:

power meter to [VHF

Frequency : 10.850 MHz

ANT] connector.

Level

: 18 mV* (–22 dBm)

Modulation : OFF

4

• Display frequency: 146.0000 MHz

Maximum output

PA

C659

• Set an SSG as:

power

Level

: 0.79 µV* (–2 dBm)

• Transmitting

IF PEAK

1

• Display frequency: Any

MAIN

Connect an RF volt-

Maximum level

MAIN

L2, L3

• Mode

: USB

meter to check point

• MIC gain

: Center

J51 via the JIG cable

• Connect an audio generator to

(B).

[MIC] connector and set as:

Frequency

: 1.5 kHz

Level

: 2 mVrms

• Transmitting

CARRIER

1

• Display frequency: Any

MAIN

Connect a spectrum

Minimum carrier level

MAIN

R206,

SUPPRESSION

• Mode

: USB

analyzer

to

check

R215

• Mic gain

: Minimum

point J51 via the JIG

• Apply no audio signals to [MIC]

cable (B).

connector.

• Transmitting

2

• Mode

: LSB

• Transmitting

3

• Repeat step 1, step 2 several times.

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