Roberts Radio 32-2054 User Manual

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www.radioshack.com
SM
OWNER’S MANUAL — Please read before using this equipment.
32-2054
Thank you for purchasing the RadioShack 40W AC/DC PA Amplifier. It gives you the versatility and power you need in a professional sound system. Your amplifier’ s wide frequency response easily handles ampli ficat io n of voi ce and musi c. Use it in meeting halls and audit oriums, at sports events, in schools, and in the office for paging syst ems - anywhere you need to deliver spec ial announcements with excellent sound.
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If an icon appears at the end of a paragraph, go to the box on that page with the corresponding icon for pertinent information.
— Caution ± — Note
© 2004 RadioShack Corporation.
All Rights Reserved.
RadioShack and RadioS hac k.co m
are trademarks used by
RadioShack Corporation.
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).
Front View of Amplifier
Phono/Aux Rotary Volume Control - lets you adjust the volume of the turntable or auxiliary sound source (See Page 15).
On/Off Rocker Switch with LED Indicator - lights to indicate power is turned on (See Page 15).
Output Power Level LED Indicator - lets you monitor and
control the output power level (See Page 15).
Microphone Rotary Volume Controls - lets you adjust the
microphone level (see Page 15).
MIC 1 and MIC 2 Input Jacks
- let you connect up to two
dynamic microphones (See Page 6).
Phones Jack - lets you connect headphones so you can hear the mixed audio in privacy (See Page 16).
Rotary MASTER Volume Control - lets you adjust the overall sound level (See Page 15
100 Hz/1kHz/8kHz Tone Controls - let you
enhance the sound or tailor the high, midrange, and low frequencies for each audio source input to the acoustics of a particular performance environment (See Page 15).
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Rear View of Amplifier
COM/4
/8/16Ω/70V Speaker
Connectors - let you easily connect speaker wires directly to the amplifier after the total speaker impedance is determined (See Page 9).
DC 5A/12V Input Jack - lets you power the amplifier from a 12V vehicle battery source
(See Page 15).
Ground Screw - connect the
ground wire (black or green) to this screw to avoid low-frequency hum.
AC IN - supports other music instrument/amplifier power with maximum load of 100W (See
Page 14).
Phono to AUX/CD Slide Switch - selects turntable
or auxiliary CD sound source (See Page 6).
Phono Jacks - let you connect a turntable (See
Page 6).
Mix Bus Jack - connects extra amplifier for multiple audio source
(See Page 7).
AUX/CD Input Jack - lets you
connect a variety of audio input sources for music and special effects (See Page 6).
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Preparation ............................ 4
Placing the Amplifier .......... 4
Placing the Speakers ......... 4
Presetting the Controls ...... 4
Preparation
Connections .......................... 5
Connecting Input Sources... 5
Connecting the Speakers.....7
One Speaker...................9
Two Speakers in Series..9 Two Speakers in
Parallel ..........................10
Series/Paral le l Comb. ...11
Speakers w/Transform. .12
Connecting Power ............... 15
Connecting the DC Jack ....15
Replacing the DC
Power Cord’s Fuse ............15
Operation ............................. 15
Monitoring Sound.............. 15
Listening Safely ................ 15
Troubleshooting ................... 16
Care ..................................... 17
Service and Repair .............. 17
Specifications ...................... 18
Accessories...........................19
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Before you use your amplif ier, be sure to place it o n a location with adeq uate ventil ation. Do not put it on thick carpeting (whic h can restrict a ir flow) o r ne ar a heat source, such as a heat vent or radiator (which can cause it to overheat).
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Speaker placement depends on your room’s size and arrangement. We recommend you play a wide-range recording and experiment with speaker placement until you find the locations that result in the best sound. For the best results, point the speakers in toward the listeners, especially if you place the speakers far apart so their coverage areas overlap to prevent dead spots (areas not covered by the speaker’s sound). Position the speakers slightly above the level of the listeners’ heads and be sure y ou have det ermined th e correct speaker impedance (see “Connecting the Speakers” on Page 7).
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Before you begin maki ng conn ection s or usin g your amplifier, preset the audio input sou rces’ and amplifier’s control s to avoid overdriving a channel o r producing loud sounds .
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Set the audio input s ources ’ control s to th ese l evels.
Audio Device Control Setting
Turntable Power Off
Tape Deck Power Off
CD Player P ower Off
Amplifier Receiver
Power
Tone
Off
Flat
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Warning: To prevent possible hearing loss, set the amplifier’s controls to the settings shown below.
Control Setting
Power Out
MIC 1, MIC 2, PHONO/AUX MIN
100 Hz, 1 kHz, 8 kHz 0dB (mid position)
MASTER VOLUME MIN
After you turn on the amplifier or change the program source, set the controls to a comforta ble listening level.
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You can connect optional components, such as microphones, tuners, turntables, or CD players to your amplifier to expand your system. To prevent hum and other noise , use lo w-ca pacita nce shie lde d cable. Your local RadioShack store carries a wide selection of audio components and connecting cable.
Connections
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You can connect one dynamic microphone (not supplied) to MIC 1 and another to MIC 2 using a 1/4” (6.35 mm) plug.
Connections
MIC 1
MIC 2
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You can connect a low level audio input source, such as a magnetic cartridge turntable, to the amplifier’s L and R PHONO jacks. With this connection, set the PHONO and AUX/CD selector switch to PHONO.
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You can connect an y high -level sound source , su ch as a CD player, tape deck, or tuner, to the amplifier’s AUX/CD jack.
AUX/CD Jack
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You can connect another MP-40 amplifier to this jack (shown on page 3) to double the size of your PA system. This lets you use up to four microphones and two turntables (or two auxiliaries) sound sources.
Use a shielded cable with phono plugs at each end to connect the amp lifier. Conn ect the cable between the two amplifiers’ MIX BUS jacks. For the best results, use the most appropriate cable length.
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You can connect one or more 4-, 8- or 16-ohm speakers to the amplifier, with or without transformers. To ensure equal volume from each speaker, all the connected speakers should have the same impedance rating.
Proper phasing is important when you use more than one speaker in the same room or area. Out-of-phase speakers can lose up to one-half of their potential volume, and can have a significantly decreased bass effect
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Most speaker terminals are color-coded or have a mark that indicates the terminal’s polarity. Usually, terminals with positive polari ty are red or have a plus (+) symbol, and terminals with negative polarity are black or have a minus (-) symbol. Phasing is correct when you connect + to + and - to -.
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Before you connect speakers to the amplifier, you must determine the total speaker impedance.
To determine total speaker impedance, you must first decide if you are connecting the speakers in series, parallel, or a series/parallel combination.
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Proper phasing occurs when speakers are set to allow sound to flow in the same direction.
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• A total speaker impedance higher than 16 ohms or lower than 4 ohms can damage your amplifier.
• When determining the total speaker impeda nc e, fir s t determine whether you are connecting the speakers in series, parallel, or a series/ parallel combination.
Connections
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For the best results when connecting speakers (in series or parallel), only use speakers having the same impedance.
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If you connect speakers
Connections
without transformers, the speaker wire should be no longer than 50 feet (See “Connecting Speakers with Transformers” on page 13).
Important: If you are connecting more than two speakers in series only or parallel only, be sure the total impedance does not exceed the amplifier’s maximum impedance (16 ohms) or fall below the minimum impedance (4 ohms). You can achieve a proper total impedance by combining series and parallel connections
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Use the shortest length of wire possible to connect the speakers. After placing the speakers in the desired location, determine the wire length and choose the appropriate gauge size.
Wire Length Wire Gauge
25 feet or less 18-gauge
Over 25 feet 16-gauge
• Use a wire stripper (not supplied) to remove about half-inch of insulation from the end of the speak er wire.
±
Wire Stripper
• Then, attach a wire connector (not supplied) and twist
Wire
Connector
the exposed wire to secure all of the wire strands.
• To connect the speaker wire to the amplifier, press down the appropriate push terminal lever on the amplifier a nd insert the end of the wire into the terminal’s hole. Then, release the lever to secure the wire.
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Connect the speaker’s negative (-) terminal to the amplifier’s COM terminal. Then, connect the speaker’s positive (+) terminal to the speaker terminal (4 speaker’s impedance.
, 8 Ω, or 16 Ω) that matches the
Speaker Terminals
Connections
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Speakers are connected in series when the first speaker’s positive terminal is connected to the next speaker’s negative terminal.
• Determine the total speaker impedance of speakers you want to connect in series by adding up the individual impedances of all the connected speakers.
For example: If connecting two 4-ohm speakers in series, your total speaker impedance is 8 ohms.
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Connections
Follow these steps to connect speakers in series.
1. Connect the first speaker’s positive terminal to the other speaker’s negative terminal.
2. Connect the first spe aker’s negative terminal to the amplifier’s COM terminal.
3. Connect the other speaker’s positive terminal to the amplifier’s terminal (4 that matches the total speaker impedance.
, 8 , or 16 Ω)
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Speakers are connected in parallel when all speakers’ negative terminals are connected together and all their positive terminals are connected together.
• Determine the total speaker impedance of speakers you want to connect in parallel by dividing the impedance of one speaker by the number of speakers.
For example: If connecting two 8-ohm speakers in parallel, divide 8 (one speaker’s impedance) by 2 (number of speakers). Your total speaker impedance is 4.
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Follow these steps to connect two speakers in parallel.
1. Connect both speaker’s negative (-) terminals to each other. Then, connect both wires to the amplifier’s COM terminal.
2. Connect both speakers’ positive (+) terminals to each other. Then, connect both wires to the amplifier’s speaker termi nal (4 that matches the total speaker impedance.
, 8 , or 16 Ω)
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Follow these steps to combine series and parallel combinations
1. Group the four speakers into two pairs.
2. Connect each pair of speakers in series. If you connected 8-ohm speakers, the total impedance of each pair is 16 ohms (8+8 = 16).
±.
Connections
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If each of the four speakers is 8 ohms, the total speaker impedance of the combined series/parallel connection described at right is also 8 ohms. Likewise, the total speaker impedance is 4 or 16 ohms if the speakers are 4 or 16 ohms, respectively.
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Connections
3. Connect each pair of speakers in parallel. If you connected 8-ohm speakers, the total impedance of both pairs is 8 ohms (16/2 = 8).
4. Connect the speakers’ negativ e (-) termina ls to the amplifier’s COM terminal.
5. Connect the speakers’ positive (+) terminals to the amplifier’s (4 Ω, 8 , or 16 ) terminal that matches the total speaker impedance, as calculated in Step 3.
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For the best results when you connect two or more speakers to your system, you can use a line transformer (not included) for each speak er.
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Transformers allow you to:
• connect speakers with different impedances without causing output di fferences between the speakers.
• add or remove a speaker from the system without having to recalculate the entire system’s impedance.
• reduce signal loss when you use speaker wire over 50 feet (15.24 meters) long.
Line transformers have several connectors called taps. The primary taps on one side of the transformer are the inputs, and are rated in watts. The secondary taps on the other side of the transformer are the outputs, and are rated in ohms.
Follow these steps to connect the speak ers with th e transformers. Example shown on next page.
1. Connect a wire from the amplifier’s 70V terminal to the transformer’s desired primary tap (10, 5, 2.5, 1.25 or 0.62 watts).
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2. Connect a wire from the amplifier’s COM terminal to the C (common) taps on the transformer’s primary side.
3. Connect a wire from the speaker’s positive (+) terminal to the t ransformer’s secon dary tap that matches the speaker’s total impedance
, 8 , or 16 Ω).
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4. Connect a wire from the speaker’s negative (-) terminal to the C (common) tap on the transformer’s secondary side.
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• Before you c onnect the speakers, be sure the total wattage of the primary tap you use does not exceed the amplifier’s maximum 40-watt output power rating.
• Avoid multiple connections to the amplifier’s 70V and COM terminals.
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Usually, a speaker in a system uses the same wattage tap. If you want a particular speaker to have a higher volume level, connec t the wire from t he 70V terminal to a higher wattage tap on its transformer.
Connections
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Connections
Amplifier
Note: The wires labeled with an A are connected to each other.
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To connect the amplifier to power, plug the female end of the supplied AC power cord into the amplifier’s AC IN jack and the other end to any standard AC outlet.
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To power the amplifier from your vehicle’s 12V battery, plug the supplied DC power cable’s barrel plug to the DC 12V IN jack, and then connect the other end to your vehicle’s 12V accessory socket, such as a cigarette-lighter socket.
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If the amplifier does not operate from a 12V battery source, check the fuse in the cigarette lighter plug. If the fuse is blown, remove the cap of the plug and replace the fuse with the proper type and rating (6A/250V).
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Follow these steps to use your amplifier.
1. Set the ON/OFF switch to the ON position.
2. Start the input sound source.
3. Set MASTER VOLUME approximately to the mid-position. The LEVEL indicator on the front panel flashes from the left to the right showing the sound level.
4. Adjust the following controls to the desired volume and balance: MIC 1, MIC 2,
PHONO/AUX, 100Hz, 1kHz, 8 kHz
5. After you get the desired balance, adjust the MASTER VOLUME to the desired volume level.
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To monitor the sound sources, insert the 1/4-inch (6.35 mm) plug of either m ono or stere o headphon e (not supplied) into the am plifie r’s PHONES jack Using headphones lets you easily check and adjust the sound sources’ balance.
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WARNING: To reduce the risk of fire or shock
hazard, do not expose this product t o rain or moisture.
..CAUTION..
RISK OF ELECTRIC SHOCK
CAUTION: TO REDUCE THE RISK OF ELECTRIC
SHOCK, DO NOT REMOVE COVER OR BACK. NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.
DO NOT OPEN
The lightning symbol is intended to alert you to the presence of uninsulated dangerous volta ge within this product’s enclos ure th at might be of sufficient magnitude to constitute a risk of electric shock. Do not open the product’s case.
The exclamation symbol is intended to inf orm you that important operating and maintenance instructions are included in the literature
!
accompanying this product.
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• Your vehicl e must have a negative ground electrical system. If you are not sure, check with your vehicle dealer.
• Unplug the AC power cord before you connect the DC power cable. Likewise, disconnect the DC power cabl e before you plug in the AC pow er cord.
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Operation
Operation
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To protect your hearing, follow these guidelines.
• Always start by setting the vol ume to the lowe st level possible before you begin listening.
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Troubleshooting
• Put the headphones on, and then gradually increase the volume to your desired listening level.
• Do not listen at extremely high volume levels. Extended high-volume listening can lead to permanent hearing loss.
• Once you set the volume, do not increase it. Over time, your ears adapt to the volume level, so a volume level that does not cause discomfort might still damage your hearing.
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We do not expect you to have any problems with your amplifier. But if you do, these suggestions might help.
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No power.
No sound.
Feedback.
16
Sound source or speakers not connected properly.
Amplifier’s MASTER
VOLUME, MIC 1, MIC 2, PHONO/AUX, 100 Hz, 1kHz, 8 kHz controls set to
minimum. Sound source or speakers
are not connected properly. A microphone or cable
might be faulty. The speaker’s wires might
be the wrong impedance.
The speaker’s wires might be too small.
The amplifier might have shut down.
Microphones or speakers are too close together.
Check all connections.
Adjust the volume control to desired setting.
Check all connections.
Check all microphones and cables.
Make sure all connected speakers have the same impedance rating.
Make sure the speaker’s wires are the correct gauge according to length.
Turn the amplifier off and let it cool. Make sure the amplifier is properly ventilated, and then turn it back on.
Reposition the microphones and speakers.
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• Keep the amplifier dry; if it gets wet, wipe it dry immediately.
• Use and store the amplifier only in room temperature environments.
• Handle the amplifier carefully; do not drop it.
• Keep the amplifi er away fro m dust and dirt, and wipe it with a dam p cloth oc casiona lly to ke ep it looking new.
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If your amplifier is not performing a s it should, ta ke it to your local RadioShack store for assistance. To locate your nearest RadioShack, use the store locator feature on RadioShack 's websi te (www.radioshack.com), or call 1-800-The Shack (843-7422) and follow the menu options. Modifying or tampering with the amplifier’s internal components can cause a malfunction and might invalidate its warranty.
Care
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Specifications
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Output Power at THD 10%, 4-Ohm Load 1 kHz ....... 40W
Total Harmonic Distortion (at 5 Watts, 4 ohms, 1 kHz, with Band Pass Filter)
MIC...................................................................0.50%
AUX..................................................................0.10%
PHONO............................................................0.30%
Input Sensitivity (at 10%, THD, 1kHz)
MIC..................................................................2.5 mV
AUX ................................................................ 150 mV
PHONO............................................................3.5mV
Signal to Noise Ratio with A-WTD
MIC....................................................................60 dB
AUX.................... ..................................... ..........80 dB
PHONO.............................................................70 dB
Hum and Noise at 4 ohms
At MASTER VOLUME MIN....................... .........1 mV
At MASTER VOLUM MAX.................. .............50 mV
Power Requirements................................120V AC 60 Hz
12VDC
Dimensions ............3 3/8 X 12 3/4 X 8 7/8 inches (HWD)
(8.5 X 32.4 X 22.6 cm)
Specifications are typical; individual units might vary. Specifications are subject to change and improvement without notice.
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The following acces sories ar e availab le at your local Radi oShack st ore. To loca te your nearest Radi oSha ck , u se th e s to re l oc ato r fe atu r e o n Radi oShack’s webs ite (www.radioshack.com), or call 1-800-The Shack (843-7422) and follow the menu options.
Transformer
Unidirectional Dynamic Microphones
Headphones
Wire
Connector
Speaker Wire
Wire Stripp er
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Limited One-Year Warranty
This product is war ran ted by R ad ioShack against manufact urin g defects in material and wor k ma n­ship under normal use for one (1) year from the date of purchase from RadioShack company­owned stores and authorized RadioShack franchisees and dealers. EXCEPT AS PROVIDED HEREIN, RadioShack MAKES NO EXPRESS WARRANTIES AND ANY IMPLIED WARRANTIES, INCLUDING THOSE OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED IN DURATION TO THE DURATION OF THE WRITTEN LIMITED WARRANTIES CONTAINED HEREIN. EXCEPT AS PROVIDED HEREIN, RadioShack SHALL HAVE NO LIABIL­ITY OR RESPONSIBILITY TO CUSTOMER OR ANY OTHER PERSON OR ENTITY WITH RE­SPECT TO ANY LIABILITY, LOSS OR DAMAGE CAUSED DIRECTLY OR INDIRECTLY BY USE OR PERFORMANCE OF THE PRODUCT OR ARISING OUT OF ANY BREACH O F THIS WAR­RANTY, INCLUDING, BUT NOT LIMITED TO, ANY DAMAGES RESULTING FROM INCONVE­NIENCE, LOSS OF TIME, DATA, PROPERTY, REVENUE, OR PROFIT OR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, EVEN IF RadioShack HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Some states do not allow limitatio ns on how long an implied wa rra nty la sts or the excl u sion or limi­tation of incidental or consequential damages, so the above limitations or exclusions may not apply to you. In the event of a product defect during the war ranty period, take the prod uct and the RadioShac k sales receipt as proof of purchase date to any RadioShack store. RadioShack will, at its option, un­less otherwise provided by law: (a) correct the defect by product repair without charge for parts and labor; (b) replace the prod uct with one of the same or simi lar design; or (c) refund the purchase price. All replaced parts and pr oducts, and p roducts on w hich a re fund i s made, be come th e prop­erty of RadioShack. New or recondit ioned parts an d produc ts may b e used in the per formance of warranty service. Re paired or r eplaced parts and produ cts are wa rranted for the r emainder of the original warranty period. You will be charged for repair or replacement of the product made after the expiration of the warranty period. This warranty does not cover: (a) damage or failure caused by or attributable to acts of God, abuse, accident, misuse, improper or abnormal usage, failure to follow instructions, improper installation or maintenance, alteratio n, lightning or other incidence of excess voltage or curr ent; (b) any repair s other than those provided by a RadioShack Authorized Service Facility; (c) consuma bles such as fuses or batteries; (d) cosmetic damage; (e) transportation, shipping or insurance costs; or (f) costs of product removal, installation, set-up service adjustment or reinstallation. This warranty gives you spec ific legal rights, and you may also have o ther rights which vary fr om state to state.
RadioShack Customer Relations, 200 Taylor Street, 6th Floor, Fort Worth, TX 76102
12/99
Printed in China
32-205401A04
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