JBL CS80
ACTIVE SUBWOOFER SCHEMATIC AND TEST
Equipment needed:
# Function/signal generator/sweep generator
# Integrated Amplifier
# Multimeter
# Speaker cables
General Unit Function (UUT = Unit Under Test)
1) From the signal generator, connect one line level (RCA) cable to the Subwoofer Line Level Input jacks L/R on the UUT. Use a Y-cable from a mono source if necessary to connect to both inputs. Do not connect to the single LFE input.
2) Turn the LEVEL control on the UUT to completely counterclockwise (MIN).
3) Turn on generator; adjust to 75mV, 50 Hz.
4) Plug in UUT; turn the power switch ON. LED should switch from Red to Green. Turn LEVEL control full clockwise (MAX)
5) LED should Green; immediate and vigorous bass response should be heard and felt from port tube opening.
6) Turn off generator, turn LEVEL control full counterclockwise (MIN), and disconnect RCA cable.
Sweep Function
1) Follow steps 1-5 above, using a sweep generator as a signal source.
2) Sweep generator from 20Hz to 300Hz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or any other noises. If any unusual noises are heard, remove woofers and test.
Driver Function
1) Remove woofer from cabinet; detach + and - wire clips.
2) Check DC resistance of woofer; it should be 3.4 ohms ±10%
3) Connect a pair of speaker cables to driver 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 5.0V.
4) Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.
# Function/signal generator/sweep generator
# Integrated Amplifier
# Multimeter
# Speaker cables
General Unit Function (UUT = Unit Under Test)
1) From the signal generator, connect one line level (RCA) cable to the Subwoofer Line Level Input jacks L/R on the UUT. Use a Y-cable from a mono source if necessary to connect to both inputs. Do not connect to the single LFE input.
2) Turn the LEVEL control on the UUT to completely counterclockwise (MIN).
3) Turn on generator; adjust to 75mV, 50 Hz.
4) Plug in UUT; turn the power switch ON. LED should switch from Red to Green. Turn LEVEL control full clockwise (MAX)
5) LED should Green; immediate and vigorous bass response should be heard and felt from port tube opening.
6) Turn off generator, turn LEVEL control full counterclockwise (MIN), and disconnect RCA cable.
Sweep Function
1) Follow steps 1-5 above, using a sweep generator as a signal source.
2) Sweep generator from 20Hz to 300Hz. Listen to the cabinet and drivers for any rattles, clicks, buzzes or any other noises. If any unusual noises are heard, remove woofers and test.
Driver Function
1) Remove woofer from cabinet; detach + and - wire clips.
2) Check DC resistance of woofer; it should be 3.4 ohms ±10%
3) Connect a pair of speaker cables to driver 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 5.0V.
4) Sweep generator from 20Hz to 1kHz. Listen to driver for any rubbing, buzzing, or other unusual noises.
CIRCUIT DIAGRAM
CLICK ON THE IMAGE TO ZOOM IN
