GE Superadio 2 Manual

Re-typed in HTML format, remaining as faithful as possible to the original.

GENERAL		ELECTRIC
SERVICE INFORMATION

MODEL
7-2885A/B/C
FM/AM
PORTABLE RADIO

FILE TAB 7

CAUTION: THIS MANUAL IS DESIGNED FOR USE BY QUALIFIED ELECTRONIC TECHNICIANS ONLY. CONSUMER
USERS ARE URGED TO CONTACT QUALIFIED FACTORY AUTHORIZED SERVICE FACILITIES FOR REPAIRS.

FEATURES

Air-gang tuning capacitor with tuned RF on FM and AM
976mm (38") swivel whip FM antenna
200mm (7 7/8") ferrite rod AM antenna
External AM and FM antenna terminals
Ceramic IF filter plus 3 IF tuned circuits on FM
Four IF tuned circuits on AM
AFC (Automatic Frequency Control) with AFC
defeat switch for fine tuning of adjacent stations
Precision vernier tuning
Two-speaker performance:
- 6 1/2" high sensitivity speaker
- plus piezo tweeter
700mW RMS audio output
Separate bass and treble controls
Loudness control boosts bass
6 "D" size batteries (not incl.) for
up to 460 hours battery life
Two-Way power: Automatic switching
from batteries to AC when plugged in
Separate power On/OFF switch
Earphone jack for optional earphone or headphone
GE AM/FM Integrated Circuit (IC)

Optional: Earphone 5-1082, Headphone 3-5750

SERVICE SPECIFICATIONS

ELECTRICAL	120 9	Volts AC, 60 Hz Volts DC Battery
BATTERIES	6	D Size
TUNING RANGE	AM FM	530 kHz - 1630 kHz 87.5 MHz - 109 MHz
IF FREQUENCIES	AM FM	455 kHz 10.7 MHz
POWER OUTPUT 10% DISTORTION	700	mW RMS Minimum
SPEAKER	8	Ohms - Woofer
IMPEDANCE	140	Ohms -Tweeter

SENSITIVITY	AM	Better than 65 uV/M for 20 dB quieting
	FM	Better than 8 uV for 30dB quieting
POWER OUTPUT @10% DISTORTION (aVERAGE)	900	mW
MINIMUM VOLUME HUM	5 mV	or Less
CURRENT DRAIN IDLE CURRENT (Average)	AM FM	15 mA 21 mA

ALIGNMENT PROCEDURE

AM ALIGNMENT - FUNCTION SWITCH IN AM POSITION

AM Generator - RF Radiated Signal Modulated 30% at 400 Hz
	GENERATOR FREQUENCY	RADIO DIAL SETTING	INDICATOR	ADJUST	REMARKS
1.	455 kHz	Closed	Output Meter Across Speaker	T4, T5, T6, T9	Adjust for maximum. Repeat until no further improvement is noted.
2.	1630 kHz	Open		C1L	Adjust for maximum
3.	510 kHz	Closed		L5	Adjust for maximum. Repeat steps 2 and 3 until set will tune to both band end frequencies.
4.	1400 kHz	Tune to Signal		C1J, C1K	Adjust for maximum
5.	580 kHz	Tune to Signal		T10, L6	Adjust for maximum. Repeat steps 4 and 5 until no further improvement is noted.

FM ALIGNMENT - FUNCTION SWITCH IN FM POSITION

High Side of FM Sweep Generator thry a 0.04uF capacitor to TP1, Use only enough Marker Signal for Indication.
	GENERATOR FREQUENCY	RADIO DIAL SETTING	INDICATOR	ADJUST	REMARKS
1.	10.7 MHz	Open	Scope at TP2. Use Pad (See Figure 1)	T1, T2, T3	Adjust for maximum gain and symmetry. Repeat as necessary.
2.	10.7 MHz	Open	Scope at TP3. Use Pad (See Figure 2)	T7, T8	Adjust for maximum gain and symmetrical S-Curve
FM Generator - Modulated RF Radiated Signal
3.	109.0 MHz	Open	Output Meter Across Speaker	C15	Adjust for maximum.
4.	87.5 MHz	Closed		L4	Spread or compress coil wind- ings slightly to raise or lower frequency. Repeat Steps 3 and 4
5.	108.0 MHz	Tune to Signal		C1G, C1H	Adjust for maximum.
6.	88 MHz	Tune to Signal		L1, L2	Spread or compress coil wind- ings slightly to obtain optimum alignment. Repeat Steps 5 and 6

FM AFC ALIGNMENT (R17) TRIM POT

1.	Tune FM dial to a no signal area near the center of the FM Band (98 MHz).
2.	With the AFC switch S2 in OFF position, connect a high impedance voltmeter (Triplett 630-NS or equivalent) to S2 pin A1 and measure the D.C. voltage. Note: Voltemeter chosen must not cause noise in FM Band which would cause incorrect alignment.
3.	Next connect voltmeter to S2 pin A2 and adjust R17 trim pot to the same voltage as measured in Step 2. Accuracy of voltage adjustment to voltage measured in Step 2 should be better than +/- 5%.

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REPLACEMENT PARTS LIST - MODEL 7-2880A

CAT. NO. SYM. DESCRIPTION

ELECTRICAL

EA49X649 R20 Loudness Control, 100K

EA49X518 R24 Treble Control, 100K

EA49X518 R25 Bass Control, 100K

EA36X483 CF1 Ceramic Filter, 10.7 MHz

EA57X14 D1,2 Rectifier

EA16X492 D3 AC/DC Switching Diode

EA16X193 D4 Varistor, 2.4 Volt

EA16X144 D5 Zener Diode, 4.7 Volt

EA88X129 T11 Power Transformer

EA39X579 S1 AM/FM Switch

EA39X579 S2 AFC Switch

EA39X254 S3 Power On/Off Switch

EA95X225 LS101 Speaker, 8 ohm

EA95X226 LS102 Speaker. 140 ohm

TRANSISTORS and INTEGRATED CIRCUITS

NOTE: when replacing transistors and integrated

circuits with the type specified below, corresponding

changes must also be made.

CAT. NO. SYMBOL DESCRIPTION

EA15X7242 Q1 R2 (330K)

EA15X7245 Q2 R4 (470K)

EA15X7136 Q3 R7 (27K)

EA15X7174 Q4 R12 (68K)

EA15X2023 Q5 R13 (47K)

EA15X4335 Q6 R14 (82K), R21 (150K)

EA15X4336 Q7 None

EA33X8546 IC1 R18 (43K)

CAT. NO. SYM. DESCRIPTION

EA41X42 J1 Earphone Jack f/7-2885A/B

EA41X336 J1 Headphone Jack f/7-2885C

EA82X50 MS-1 Whip Antenna f/7-2885A

EA82X107 MS-1 Whip Antenna f/7-2885B/C

EA66X56 MS-2 Power Cord

EA3X264 MS-3 External Antenna Terminals

EA2X1495 MS-4 Neg. Spring Contact

EA2X196 MS-5 Neg./Pos. Spring Contact

EA1X777 MS-6 Eyelet f/Spring Contact

EA2X1496 MS-7 Pos. Contact

EA98X976 MS-8 Cab. Front Ass'y. f/7-2885A/B

EA98X1029 MS-8 Cab. Front Ass'y f/7-288SC

EA98X977 MS-9 Cab. Back Ass'y f/7-2885A

EA98X1028 MS-9 Cab. Back Ass'y f/7-2885B

EA98X1030 MS-9 Cab. Back Ass'y f/7-2885C

EA9X700 MS-10 Battery Compartment Door

EA78X92 MS-11 Handle

EA4X798 MS-12 Handle End Cap

EA43X1634 MS-13 Tuning Knob

EA43X960 MS-14 ON/OFF Knob

EA43X1373 MS-15 Treble Control Knob

EA43X1373 MS-16 Bass Control Knob

EA43X1373 MS-17 Loudness Knob

EA4X921 MS-18 Monogram Insert

EA89X301 MS-19 Grille w/Monogram

EA4X799 MS-20 Control Insert

NOTE: MS Reference is for factory use only.

Capacitors and items not listed are non-stocked items.

All Capacitors should be replaced with same type, size

and Voltage rating as original.

Replacement parts may be ordered from: General Electric Company, National Parts Distribution, P. O. Box 7025,
Charlotte, N.C. 28217 or in CANADA - Canadian General Electric, 80 Bradford Street, P. O. Box 1060, Barrie,
Ontario L4M5E1.

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