Sunday, November 29, 2015

JBL 1500 ARRAY ACTIVE SUBWOOFER TEST PROCEDURE AND CIRCUIT DIAGRAM

ACTIVE SUBWOOFER 

JBL 1500 ARRAY 

TEST PROCEDURE AND CIRCUIT DIAGRAM 

1500 ARRAY OPERATION
Power On
Plug your subwoofer’s AC cord into a wall outlet. Do not use the outlets on the back of the receiver. Initially set the Subwoofer Level (Volume) Control  to the “min” position. Turn on your sub by pressing the Power Switch a on the rear panel.
Auto On/Standby
With the Power Switch a in the “on” position, the Power Indicator LED  will remain backlit in red or green to indicate the On/Standby mode of the subwoofer. RED = STANDBY (No signal detected, Amp Off) GREEN = ON (Signal detected, Amp On)
The subwoofer will automatically enter the Standby mode after approximately 10 minutes when no signal is detected from your system. The subwoofer will then power ON instantly when a signal is detected. During periods of normal use, the Power Switch a can be left on. You may turn off the Power Switch  for extended periods of nonoperation, e.g., when you are
away on vacation. If the Auto Switch   is in the “on” position, the subwoofer will remain on.
Adjust Level
Turn on your entire audio system and start a CD or movie soundtrack at a moderate level. Turn up the Subwoofer Level (Volume) Control  about halfway. If no sound emanates from the subwoofer, check the AC-line cord and input cables. Are the connectors on the cables making proper contact? Is the AC 
plug connected to a “live” receptacle? Has the Power Switch been pressed to the “on” position? Once you have confirmed that the subwoofer is active, proceed by playing a CD or movie. Use a selection that has ample bass information. Set the overall volume control of the preamplifier or stereo to a comfortable level. Adjust the Subwoofer Level (Volume) Control  until you obtain a pleasing blend of bass. Bass response should not overpower the room but rather should be adjusted so there is a harmonious blend across the entire musical range. Many users have a tendency to set the subwoofer volume too loud, adhering to the belief that a subwoofer is there to produce lots of bass. This is not entirely true. A subwoofer is there to enhance bass, extending the response of the entire system so the bass can be felt as well as heard. However, overall balance must be maintained or the music will not sound natural. An experienced listener will set the volume of the subwoofer so its impact on bass response is always there but never obtrusive. 
Crossover Adjustments
NOTE: This control will have no effect if the LP/LFE Selector Switch is set to “LFE.” If you have a Dolby Digital or DTS processor/receiver, the Crossover Frequency is set by the processor/receiver. Consult your owner’s manual to learn how to view or change this setting.
The Crossover Adjustment Control ∞ determines the highest frequency at which the subwoofer reproduces sounds. If your main speakers can comfortably reproduce some low-frequency sounds, set this control to a lower frequency setting, between 50Hz and 100Hz. This will concentrate the subwoofer’s efforts on the ultradeep bass sounds required by today’s films and music. If you are using smaller bookshelf speakers that do not extend to the lower bass frequencies, set the Crossover Adjustment Control to a higher setting, between 120Hz and 150Hz.
Phase Control
The Phase Switch  determines whether the subwoofer speaker’s pistonlike action moves in and out with the main speakers (0 Degree) or opposite the main speakers (180 Degree). Proper phase adjustment depends on several variables, such as subwoofer placement and listener position. Adjust the Phase Switch to maximize bass output at the listening position.
BASIC TROUBLESHOOTING
If there is low (or no) bass output
#
Make sure the connections to the left and right “Speaker Inputs” have the correct polarity (+ and –).
# Make sure the subwoofer is plugged into an active electrical outlet.
# Make sure the Power Switch is on.
# In Dolby Digital or DTS modes, make sure your receiver/processor is configured so that the subwoofer and LFE output are enabled.
# Adjust the Subwoofer Level Control
1500 Array TEST PROCEDURE
Equipment needed:
# Function/signal generator/sweep generator
# Multimeter
# RCA cable
General Unit Function (UUT = Unit Under Test)
Switch/Controls:
GAIN control full Counterclockwise (Min)
CROSSOVER (Hz) Full Clockwise (140)
PHASE switch - either position
LFE/LP – LP position
1) From the signal generator, connect one line level (RCA) cable to the Line In jack on the UUT.
2) Turn on generator; adjust to 200mV, 50 Hz.
3) Plug AC power cord in UUT, turn power switch ON.
4) LED should be ON (faceplate). Turn up LEVEL control to full Clockwise (Max).
5) LED should be Green; Bass response should be heard and felt vigorously from woofer and port tube.
6) Turn LEVEL control full Counterclockwise (Min). Turn power switch OFF.
Sweep Function
1) Follow steps 1-5 above, using a sweep generator as a signal source – adjust the generator to 75mV, 50 Hz.
2) Sweep generator from 20Hz to 300Hz. Listen for any rattles, clicks, buzzes or any other noises. If any unusual
noises are heard, test woofer according to the instructions below.
Driver Function
1) Remove woofer from the enclosure.
2) Check DC resistance of woofer; it should be
5.9 Ohm +/-10%,
3) Connect a pair of speaker cables to woofer terminals. Cables should be connected to an integrated amplifier
fed by a signal generator. Turn on generator and adjust so that speaker level output is 6.0V.
4) Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.
CIRCUIT DIAGRAM
CLICK ON THE IMAGES TO ZOOM IN