BOSE 321 - 321GS - 321GSX SERIES II – CONSOLE TEST PROCEDURE – BASS MODULE TEST PROCEDURE – SATELLITE SPEAKERS TEST PROCEDURE - AUDIO SYSTEM REPAIR AND SERVICE

BOSE 321 - 321GS - 321GSX Series II – Console Test procedure – Bass module test procedure – Satellite speakers test procedure - Audio system repair and service

Category: Audio System Repair and Service 

Contents of this article 

• Console test procedures 
• Bass Module test procedures
• Satellite Test procedures 

 

BOSE 321 - 321GS - 321GSX Series II

Console Test 
CAUTION: The DVD drive mechanism should not be closed by pushing it shut with no power applied to the console. Doing so could damage the drive. It must be closed with power applied so that the locking mechanism inside the drive will engage properly when the drawer is closed.
Equipment required:
# Console test cable with DC power supply or bass module w/system cable
# Audio signal generator
# Digital multimeter
# Analog to S/PDIF converter
# S/PDIF to optical converter
# AM/FM signal generator
# Video signal generator or DVD player
# Abex test DVD (TDV-540A)
# Video monitor
# Composite Video cable
# S-Video cable
# Optical cable
# Oscilloscope
# Model 321 Series II remote control
1. Analog Audio Test
1.1 Apply a 1 Vrms, 1 kHz signal to the left and right AUX audio analog inputs.
1.2 On the console, select the AUX input. Press the volume up (+) button on the console for 10 seconds to put it at full volume.
1.3 Measure the output level at the left and right audio outputs on the console test cable. It should be 470 mVrms + 10%.
1.4 Repeat steps 1.1 to 1.3 for the CBL-SAT and TV audio analog inputs.

2. Coaxial Digital Audio Test
2.1 Connect the audio signal generator to the input of the analog to S/PDIF converter.
2.2 Connect the output of the S/PDIF converter to the AUX coaxial digital input.
2.3 Apply a 500 mV, 1 kHz signal to the analog input of the S/PDIF converter. Reference a dB meter to the signal generator output signal.
2.4 On the console, select the AUX source. Press the volume up (+) button on the console for 10 seconds to put it at full volume.
2.5 Measure the output signal level at the analog outputs of the console test cable. The output should be 0 dB, +0.5/-1.5 dBr.
2.6 Measure the distortion level of the analog output signal at the left and right analog outputs of the test cable. The distortion level should be 0.07% maximum.
2.7 Repeat steps 2.1 to 2.6 for the CBL-SAT digital coaxial input.
2.8 Repeat steps 2.1 to 2.6 for the TV digital coaxial input.
3. Optical Digital Audio Test
3.1 Connect the audio signal generator to the input of the analog to S/PDIF converter.
3.2 Connect the output of the S/PDIF converter to the input of the S/PDIF to optical converter.
3.3 Connect the output of the optical converter to the VIDEO 1 optical input.
3.4 Apply a 250 mV, 1 kHz signal to the analog input of the S/PDIF converter. Reference a dB meter to the signal generator output signal.

3.5 On the console, select the VIDEO 1 source. Press the volume up (+) button on the console for 10 seconds to put it at full volume.
3.6 Measure the output signal level at the analog outputs of the console test cable. The output should be 0 dB, +0.5/-1.5 dBr.
4. Video Tests
4.1 Connect the video generator or DVD player to the COMPOSITE VIDEO INPUT only.
4.2 Connect the video monitor to the COMPOSITE VIDEO OUTPUT.
4.3 Set the video generator to display a test pattern. If using a DVD player, load a DVD disc into the tray and start playback.
4.4 On the console, select the VIDEO 1 source.
4.5 Confirm that the test pattern or DVD video appears on the video monitor and thatthere are no obvious video problems.
4.6 Connect the video generator or DVD player to the S-VIDEO input only.
4.7 Connect the video monitor to the S-VIDEO output.
4.8 Set the video generator to display a test pattern. If using a DVD player, load a DVD disc into the tray and start playback.
4.9 On the console, select the VIDEO 1 source.
4.10 Confirm that the test pattern or DVD video appears on the video monitor and that there are no obvious video problems.
5. Internal DVD Video Test
5.1 Load the test DVD into the console.

5.2 Connect the video monitor to the S-VIDEO output of the console.
5.3 On the 321 Series II system remote control, press the CD-DVD button to start playback of the DVD disc.
5.4 Confirm that the test pattern or DVD video appears on the video monitor and that there are no obvious video problems.
6. DVD Audio Test
6.1 Load the test DVD into the console.
6.2 If necessary, connect the satellite arrays to the 9-pin D-sub connector.
6.3 On the 321 Series II system remote control, press the CD-DVD button to start playback of the DVD disc.
6.4 Verify that the audio plays.
7. CD Playability Tests
Test discs required:
ABEX TCD-714R
ABEX TCD-721R
ABEX TCD-725R
ABEX TCD-732R
Philips TS4
7.1 Insert the ABEX TCD-725R test disc into the console CD/DVD tray.
# Play the defect tracking (interruption) track. Verify that the track plays properly. The nominal is a 1.0 mm defect, 0.8 mm limit.
# Play the defect tracking (black dot) track. Verify that the track plays properly. The nominal is a 1.0 mm defect, 0.8 mm limit.
# Play the defect tracking (fingerprint) track. Verfiy that the track plays properly. The nominal is a 75 um defect, 65 um limit.

7.2 Insert the ABEX TCD-721R test disc into the console CD/DVD tray. Play the defect tracking (scratch) track. Verify that the disc plays properly. The nominal is a 1.6 mm defect, 1.0 mm limit.
7.3 Insert the ABEX TCD-714R test disc into the console CD/DVD tray. Play the defect tracking (eccentric disc) track. Verify that the disc plays properly. The nominal is a 280 um defect, 210 um limit.
7.4 Insert the ABEX TCD-732R test disc into the console CD/DVD tray. Play the defect tracking (warped disc) track. Verify that the disc plays properly. The nominal is a 1.0 mm defect, 0.7 mm limit.
7.5 Insert the Philips TS4 test disc into the console CD/DVD tray. Play tracks 1 through 15, verifying that each track cues up within the test limits. Nominal is 2 seconds or less, limit 3 seconds.
321 Series II Console Tuner Adjustments / Measurements
The following tests can be performed without the use of an IBM compatible PC.
AM Adjustments
For all AM alignments and tests plug the AM antenna into the console and position it 2 feet away from the unit. Configure the AM antenna, a standard test loop and RF generator as shown below to create the specified field strength for each test. The equivalent field intensity in dBuV/m is 20 dB less than the generator output level in dBuV emf at the receiving antenna. The signal levels given do not include this factor.

AM Loop Antenna Test Setup

8. AM RF Tracking
Note: In order to perform this test, you will need to partially disassemble the console.
# Eject the DVD/CD drawer and remove the drawer bezel.
# Remove the console front bezel.
# Remove the top cover.
# Lift out the tuner PCB. Disconnect the ribbon cable. Remove the metal cover. Reconnect the ribbon cable and place the board so that you can adjust the tuner slugs on T2000.
8.1 Connect an AC meter to the left or right analog output jack on the console test cable.
8.2 Inject a 1500 kHz (US, Dual Voltage) or 1503 kHz (Euro, UK, AUS and Japan) RF signal at a level of 90 dBuV emf, 30% modulation, 1 kHz modulation frequency.
8.3 Tune the console to 1500 kHz or 1503 kHz (as appropriate) and adjust the red slug (T2000) for maximum audio level at the left or right audio output. Verify that the level is greater than 40 mVrms.

8.4 Change the RF frequency to 600 kHz (US, Dual) or 603 kHz (Euro, UK, AUS and Japan) and re-tune the console to 600 kHz or 603 kHz (as appropriate).
8.5 Adjust the black slug (T2000) for maximum level. Verify that the level is greater than 40 mVrms.
8.6 Repeat steps 8.2 to 8.5 until maximum audio output is obtained without the need for further adjustment.
8.7 Replace the metal top cover over the RF circuitry. Re-install the tuner PCB into the console before continuing testing.
9. AM Sensitivity
9.1 Inject a 1080 kHz RF signal at a level of 55 dBuV emf, 30% modulation, 1 kHz modulation frequency.
9.2 Tune the console to 1080 kHz.
9.3 Measure the output level at the the console test cable audio output jacks. It should be between 70 and 320 mVrms.
9.4 Measure the distortion level of the output at the console test cable analog audio output jacks. It should be 10.0% max.
FM Adjustments
Note: Unless otherwise noted, set the RF generator for 1 kHz, mono modulation, pilot off and 75 kHz deviation. Power levels for FM testing are given in dBf at the antenna input to the unit.
Typically a test setup will consist of an RF generator with a 50 Ohm output impedance and a 50 Ohm to 75 Ohm impedance matching element. The two most commonly used impedance matching element are a resistive network which has a 5.7 dB insertion loss or a “lossless” transformer which has a 0.5 dB insertion loss.

To find the required setting in dBuV emf from a given dBf value for an RF generator with a 50 Ohm output impedance use the conversions in the following table.

Using a “lossless” transformer	Subtract 1.3 dB. eg: 65dBf => set generator to 66.8 dBuV emf
Using a resistive network (5.7dB loss)	Subtract 6.5 dB eg: 65dBf => set generator to 71.5 dBuV emf

Note: For generators with RF level resolutions of only 1 dB, round up.

10. FM Distortion Measurement / Adjustment
10.1 Inject a 98.1 MHz, 1 kHz mono, 75 kHz deviation, pilot off (83.0 MHz Japan units), RF signal at a level of 58 dBuV emf into J2001.
10.2 Tune the console to 98.1 MHz (83.0 MHz Japan units).
10.3 Measure the distortion plus noise (THD+N) at the audio output jacks. If it is less than or equal to 0.60%, verify that the audio level is between 520 and 1050 mVrms. If these are not the measurements you have, proceed to step 12.4.
10.4 If the THD+N is greater than 0.65%, or the audio level is less than 520 mV, adjust T2002 for minimum distortion. Verify that the level is greater than 520 mV and the distortion is less than 0.65%.
12. FM Sensitivity
12.1 Inject a 98.1 MHz (83 MHz for Japan units) RF signal at a level of 13 dBuV emf into J2001.
12.2 Measure the THD+N at the console test cable audio output jacks. It should be less than or equal to 3.0%.

13. FM Stereo Separation
13.1 Inject a 98.1 MHz (83.0 MHz Japan units) RF signal set to 1 kHz left only modulation with 10% pilot modulation and 75 kHz total deviation at a level 58 dBuV emf into J2001.
13.2 Reference a dB meter to the level at
the console test cable left audio output jack.
13.3 Switch the RF signal modulation to the right channel only.
13.4 Measure the level at the left audio output jack. It should read -25 dB or less.
Computer Assisted Tuner Test Procedures
Additional Equipment Required:
# IBM Compatible PC
# Console test cable with DC power supply or bass module w/system cable
# ETAP test cable
# B+B Electronics RS-232 to TTL level shifter, model 232LPTTL
Note: Refer to the computer set up instructions in the appendix for proper connection to an IBM compatible computer. Refer to the figure below, AM loop antenna test setup diagram, to achieve the proper field strength for the given RF generator setting

Some of the commands in the following tests will automatically set the calibration, requiring only an external RF signal at the input of the tuner. Other commands require the technician to make measurements and adjustments.

AM Adjustments
Place the console into TAP mode. Using the remote control or the console front panel buttons, select the AM source.
14. AM Alignment
14.1 Inject an 1500 kHz RF signal at a level of 90 dBuV emf, 30% modulation at 1 kHz.
14.2 Enter the command T1 into the computer. This will tune the unit to 1500 kHz.
14.3 You should receive the response “OK” on the computer screen. Verify that the console display shows that it is tuned to
1500 kHz.
14.4 Using a non-metallic tuning tool, adjust the red slug of T2004 for maximum output at the console test cable audio output jacks. Verify that the level is greater than 40 mVrms.
14.5 Inject a 600 kHz RF signal at a level of 90 dBuV emf, 30% modulation at 1 kHz.
14.6 Enter the command T2 into the computer. This will tune the unit to 600 kHz.
14.7 You should receive an “OK” response on the computer screen.
14.8 Using a non-metallic tuning tool, adjust the black slug of T2004 for maximum output at the console test cable audio output jacks. Verify that the level is greater than 40 mVrms.
14.9 Repeat steps 14.1 through 14.8 until the audio level is at a maximum without adjustment.

15. AM Stop Level
15.1 Inject a 1080 kHz RF signal at a level of 57 dBuV emf, 30% modulation at 1 kHz.
15.2 Enter the command T2 into the computer. This will tune the unit to 1080 kHz, then measures, reports, and stores to EEPROM the S-meter level. You should receive an “Smeter xx” response (where xx is the S-meter level) on the computer screen after inputting this command.
15.3 Apply a 1080 kHz RF signal at a level of 61 dBuV emf, 30 % modulation, 1 kHz.
15.4 Tune the console to 1000 kHz. Press the seek up >> button on the IR remote control. Verify that the console stops at 1080 kHz.
15.5 Apply a 1080 kHz RF signal at a level of 51 dBuV emf, 30 % modulation, 1 kHz.
15.6 Tune the console to 1000 kHz. Press the seek up >> button on the IR remote control. Verify that the console does not stop at 1080 kHz.
FM Tuner Tests
Note: For all FM measurements and adjustments, the RF signal is to be connected from the signal generator to J2001 via a 50 to 75 Ohm impedance matching network. Ensure the signal generator is configured a 50 Ohm output impedance, if necessary. The input levels stated below are to be as read at the input of J2001.
FM Adjustments
On the console front panel, switch the source to FM.
16. FM IF Centering Adjustment
16.1 Inject a 98.1 MHz, 1 kHz mono modulation, pilot OFF, 75 kHz deviation RF signal at a level of 43 dBuV emf into J2001.

16.4 Enter the command “T7” into the computer. The tuner micro will tune the radio, perform the IF Offset processing, and write the proper offset to EEPROM. You will receive a response of “IF Offset: x”, where x is (-1, 0, 1) representing an IF offset of (-25, 0, 25) kHz.
17. FM Distortion Measurement/ Adjustment
17.1 Inject a 98.1 MHz, 1 kHz mono modulation, pilot OFF, 75 kHz deviation RF signal at a level of 58 dBuV emf into J2001.
17.2 Enter the command TS1A8,0 into the computer. This will tune the unit to the appropriate frequency. You will get an “OK” response from the console.7
17.3 Measure the distortion plus noise (THD+N) at the console test cable audio output jacks. If it is less than or equal to 0.60%, verify that the audio level is between 520 to 1050 mVrms. If these are not the measurements you have, proceed to step 18.4.
17.4 If the THD+N is greater than 0.65%, or the audio level is not between 520 to 1050 mVrms, adjust T2001 for minimum distortion. Verify that the distortion level is now less than or equal to 0.60% and that the audio level is between 520 to 1050 mVrms.
18. FM Sensitivity
18.1 Inject a 98.1 MHz, 1 kHz mono modulation, pilot OFF, 75 kHz deviation RF signal at a level of 13 dBuV emf into J2001.
18.2 Measure the THD+N at the audio output jacks. It should be less than or equal to 3.0%.
19. FM Stereo Separation
19.1 Inject a 98.1 MHz RF signal set to 1 kHz left only modulation with 10% pilot modulation and 75 kHz total deviation at a level 58 dBuV emf into J2001.

19.2 Enter the command TS1A8,0 into the computer. You will receive an “OK” response from the console, and the unit will tune to the appropriate frequency.
19.3 Reference a dB meter to the left audio output jack on the console test cable.
19.4 Switch the RF signal modulation to theright only channel.
19.5 Measure the left audio output jack.
It should read -25 dB or less.
20. FM Stop Level
20.1 Inject a 98.1 MHz, 1 kHz mono modulation, pilot OFF, 75 kHz deviation RF signal at a level of 23 dBuV emf into J2001.
20.2 Enter the command T3. The tuner micro tunes the radio, then measures, reports, and stores to EEPROM the s-meter level. You should get a response of “Smeter: xx” from the console, where xx is the reading.
20.3 Set the RF generator for 98.9 MHz, 1 kHz mono modulation, pilot OFF, 75 kHz deviation RF signal at a level of 28 dBuV emf into J2001.
20.4 Enter the command TC5. This is the seek up command. Verify that the unit stops at 98.9 MHz.
20.5 Set the console for 98.1 MHz.
20.6 Set the RF generator for 98.9 MHz, 1 kHz mono modulation, pilot OFF, 75 kHz deviation RF signal at a level of 18 dBuV emf into J2001.
20.7 Enter the command TC5. This is the seek up command. Verify that the unit does not stop at 98.9 MHz.

21. FM Stereo & Force Mono Threshold
21.1 Inject a 98.1MHz RF signal set to 1kHz stereo L = -R modulation with 10% pilot modulation and 75 kHz total deviation at a level of 33 dBuV emf into J2001.
21.2 Enter the command T5 into the computer. The tuner micro tunes the radio, then measures, reports, and stores to EEPROM the s-meter level.
21.3 Inject a 98.1MHz RF signal set to 1kHz stereo L = -R modulation with 10% pilot modulation and 75 kHz total deviation at a level of 38 dBuV emf into J2001.
21.4 Re-tune the radio via ETAP by entering the TS1A8,0 command. You should receive an “OK” reply from the console.
21.5 Verify that the left channel audio output level at the console test cable analog outputs is > 100 mVrms. On the console display, verify that the STEREO LED is lit.
21.6 Decrease the RF generator level to a level of 28 dBuV emf into J2001.
21.7 Verify that the left channel audio output level at the console test cable analog output is < 100 mVrms. On the console display, verify that the STEREO LED is not lit, and that the console is in mono mode.
22. FM Signal to Noise Ratio
22.1 Set the RF signal generator to 98.1 MHz, 1 kHz modulation, pilot off, 75 kHz deviation and at the level that corresponds to 58 dBuV emf into J2001.
22.2 Measure the output level at the left or right console test cable analog audio output jack. Reference a dB meter to this level.
22.3 Turn off the RF modulation and verify that the level drops by > 60 dB.

23. Hard Drive Self Test (GSX consoles only)
23.1 Issue the TAP command HS (hard disk self test). You will receive an “OK” response. The test will run for two minutes.
23.2 To retrieve the test results, issue the TAP command QHC (query hard drive self test results). Refer to the table below for a list of responses. The 2nd character will count down to “0”. When the second character is a “0”, the test is complete.

XX	Result
00	Test passes.
10	Test failed. Did not complete: aborted by the host.
20	Test failed. Did not complete: interrupted by reset.
30	Test failed. Did not complete: fatal error.
40	Test failed. Test completed with unknown failure.
50	Test failed. Test completed with electrical or write element failure.
60	Test failed. Test completed with servo/seek element failure.
70	Test failed. Test completed with read element failure.
X0	Test failed. Invalid response. (X: not 0-7)

24. User Interface Tests

24.1 Press each button on the console control panel and ensure its operation.
24.1.1 With the media center off, connect an external video source to the UUT’s external video inputs. Verify that the video appears on the video monitor. Do this for both the composite and S-Video outputs on the media center.
24.1.2 Press the POWER button on the console control panel. Ensure that the unit turns on.
24.1.3 To ensure remote operation, select at least one function (i.e. FM/AM) and ensure the unit responds appropriately to the remote control.
24.1.4 Press the VOLUME UP (+) and then the VOLUME DOWN (-) button on the console control panel. Ensure that the unit responds appropriately.
24.1.5 With the radio tuned to a station, press and hold the ENTER button on the console control panel. The display shows PRESET # SET. Continue holding the ENTER button to save the preset.
24.1.6 On the GXS console only, the ENTER button is replaced by the STORE button. Insert a CD into the CD/DVD drawer and press the STORE button. Verify that the disc stores to the console. Once completed, be sure to delete the disc from the console.
24.1.7 Press either SOURCE button. Ensure, with each press, that the display cycles through the various sources.
24.1.8 Press the STOP/EJECT button. Ensure the DVD/CD drawer opens, and then press it once more to shut the drawer.
24.1.9 Press the POWER button. Ensure that the unit shuts off.

Bass Module Procedures
Equipment required:
# Audio signal generator
# dB Meter
# Distortion meter
# Digital multimeter
# 2 Ohm, 50 Watt load resistor
# Bass module test cable (see instructions in the appendix)

1. Unpowered Transformer Impedance Test
1.1 On the bass module, set the AC mains switch to the ON position (if applicable). For the International variation, set the voltage select switch to 115V.
1.2 Using a DMM, measure the transformer input impedance through the AC connector. For the dual-voltage variant, set the voltage select switch to 115V. Change the voltage select switch to 230V, and re-measure the AC input resistance. The resistance should be within the ranges specified below,

Part Number	Region	Ohms
273031-1xxxx, 273031-xxxxx	U.S./JAPAN, Taiwan	3.5 ± 15%
273031-2xxxx	International	9.8 ± 15%
273031-6xxxx	Dual-voltage (115V) (230V)	3.7 ± 15% 9.8 ± 15%

2. Woofer DC Resistance Test

2.1 Remove the bass module rear enclosure.
2.2 Remove the woofer harness from Jx on the bass module PCB. Measure the DC resistance of the woofer voice coil by measuring across the two pins of the woofer harness. It should be 1.55 Ohms + 15%

3. Power Up Test
3.1 Set up the computer to communicate smartspeaker commands with the system using the procedures in the appendix of this service manual.
3.2 Set up the bass module under test as shown in Figure 2. Apply AC mains voltage to the bass module.
3.3 Transmit two consecutive smartspeaker commands to turn on the system and remain muted. The commands should have at least 100msec spacing between them. The first command will wake the system. The second command tells the system to remain muted. The command bytes are represented in hexadecimal format: 0x01 0x00 0x00 0x01 space 0x01 0x00 0x00 0x01 The speaker should respond “0x00”.
3.4 Select the analog inputs by transmitting the following “SOURCE TYPE” message: 0x0D 0x00 0x02 0x0F The speaker should respond “0x00”.
3.5 Set the stream type by transmitting the following :STREAM METADATA” message: 0x0E 0x00 0x00 0x00 0x0E The speaker should respond “0x00”.
3.6 Transmit the smartspeaker SET MAIN ATTENUATION message to set the attenuation to 12 counts (0-100): 0x02 0x00 0x0C 0x0E The speaker should respond “0x00”.

4. Air Leak Test
4.1 Apply a 45Hz, 2.0 Vrms sine wave to the Left analog input on the system test cable.
4.2 Listen for air leaks around all cabinet seams, joints and wire harness thru-holes. Air leaks will be heard as a hissing or sputtering noise. Test duration should be 5 seconds minimum. Repair any air leaks. All repairs must be hidden.
5. Frequency Sweep Test
5.1 Apply a 2.0 Vrms, 10 Hz signal into the right analog input on the system test cable.
5.2 Sweep the input frequency from 10 Hz to 500 Hz. Listen for any extraneous noises such as buzzes, rattles, ticks, port noise or distortion.
6. Array Amplifier and Control Signal Tests
6.1 Transmit the smartspeaker SET MAIN ATTENUATION message to set the attenuation to 36 counts (0-100): 0x02 0x00 0x24 0x26
PASS: Speaker responds 0x00.
6.2 Apply a 2Vrms,1000 Hz ±1% sine wave in both left and right analog input positive terminals, J3.9 and J3.12. Ground the left and right analog input negative terminals, J3.8 and J3.10.

PASS: The voltage across the array amplifier loads lie within the following ranges: LC, RC: 2.0 to 2.9 Vrms LS, RS: 1.2 to 1.8 Vrms
6.3 Short the SPKR-SENSE input (J4.3) to the Shell of J4.
PASS: The voltage across the center array amplifier loads exceed the following values: LC, RC > 3.0 Vrms

6.4 Select the S/PDIF input by transmitting the following “SOURCE TYPE” message: 0x0D 0x00 0x03 0x0E
PASS: Speaker responds 0x00. (There is no need to repeat the “STREAM METADATA” message.)
6.5 Apply a -6dB peak value,1 kHz ± 1% PCM stream in both left and right samples of a S/PDIF signal connected differentially to the system test cable SPDIF input.
PASS: The voltage across the center array amplifier loads exceed the following values: LC, RC: > 3.0 Vrms
6.6 Apply 3.3 vdc to CONSOLE-MUTE and wait 500msec.
PASS: The voltage across the array amplifier loads are < 10 mVrms.
6.7 Open CONSOLE-MUTE.
PASS: The voltage across the array amplifier loads are > 3.0Vrms.
Satellite Array Procedures
Notes:
# The standard 321 Series II satellite arrays are non-repairable. The 321GS Series II satellite arrays are repairable.
# Each satellite array contains two identical drivers that are wired independently. You must test each of them separately unless otherwise specified.
1. DC Resistance Test
1.1 Using a DMM, measure the DC resistance of each of the array drivers. Each should measure 3.2 Ohms + 10%.

2. Phase Test
2.1 Remove the array grille
2.2 Observing polarity, apply a +6 Vdc level to one driver on the array input connector.
2.3 Observe the TwiddlerTM under test. When the DC level is applied, the driver should move outward. If it does, the Twiddler is wired correctly. If not, it is wired incorrectly. Repeat steps 2.2 and 2.3 for the other driver in the array.
3. Air Leak Test
3.1 Apply a 180 Hz, 3 Vrms signal to one of the Twiddler drivers in the satellite array for 5 seconds minimum.
3.2 Listen for air leaks around all enclosure seams, joints and the input connector. Air leaks will be heard as a hissing or sputtering noise. Repair any air leaks. All repairs must be hidden.
3.3 Listen for any rubbing or ticking noise from the Twiddler. Replace any driver that is defective.
Note: There is a normal suspension noise. To distinguish between a rub or tick and suspension noise, displace the cone slightly with your finger. If the rubbing can be made to go away or get worse, then it is a rub or tick. If the noise stays the same, it is suspension noise.
3.4 Repeat steps 3.1 to 3.3 for the other driver in the array.

4. Frequency Sweep Test
4.1 Jumper both of the drivers in a single array together. Both center pins of the array connector are negative (-). The two outer pins are the positive (+) pins.
4.2 Apply a 100 Hz, 3.0 Vrms signal to both of the array drivers.
4.3 Slowly sweep the signal generator from 100 Hz to 2.0 kHz. Listen for any extraneous noises such as buzzes, rattles, ticks, port noise or distortion. Replace any array with an extraneous noise that can be heard at a distance greater than 1 foot (0.3m).