Sub woofer schematic and alignment; Test Set Up and Procedure
Equipment
needed:
# Function/signal generator/sweep generator
# Integrated Amplifier
# Multimeter
# Speaker cables
Initial Control Settings:
# Power Switch OFF; Filter OFF
# Level MIN (Full CCW)
# Phase, Auto/On switches do not matter
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, purple SUB input.
2) Turn on generator; adjust to 75mV, 50 Hz.
3) Plug in UUT; turn the power switch ON. Turn LEVEL control full clockwise (MAX)
4) LED should turn from Amber to Blue (on top of UUT); immediate and vigorous bass response should be heard and felt from port tube opening.
5) Turn off generator, turn LEVEL control full counterclockwise (MIN), and disconnect RCA cable.
6) Connect one pair of speaker cables to Speaker Level input terminal (IN) on UUT. Cables should be connected to an integrated amplifier fed by the signal generator.
7) Turn on generator and adjust so that speaker level input at the amplifier is 1.6V, 50 Hz. Turn LEVEL control full clockwise.
8) LED should turn from Amber to Blue; immediate and vigorous bass response should be heard and felt from the port tube opening.
# Function/signal generator/sweep generator
# Integrated Amplifier
# Multimeter
# Speaker cables
Initial Control Settings:
# Power Switch OFF; Filter OFF
# Level MIN (Full CCW)
# Phase, Auto/On switches do not matter
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, purple SUB input.
2) Turn on generator; adjust to 75mV, 50 Hz.
3) Plug in UUT; turn the power switch ON. Turn LEVEL control full clockwise (MAX)
4) LED should turn from Amber to Blue (on top of UUT); immediate and vigorous bass response should be heard and felt from port tube opening.
5) Turn off generator, turn LEVEL control full counterclockwise (MIN), and disconnect RCA cable.
6) Connect one pair of speaker cables to Speaker Level input terminal (IN) on UUT. Cables should be connected to an integrated amplifier fed by the signal generator.
7) Turn on generator and adjust so that speaker level input at the amplifier is 1.6V, 50 Hz. Turn LEVEL control full clockwise.
8) LED should turn from Amber to Blue; immediate and vigorous bass response should be heard and felt from the port tube opening.
Sweep Function
1) Follow steps 6-8 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 3.0 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.
1) Follow steps 6-8 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 3.0 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.
Schematic
Improved filter
performance
Change
four 1/6W +/-5% CF Resistors in the PREAMP PCB of the HKTS 7 subwoofer
amplifier. It is recommended this procedure be followed for every unit
that has to be serviced, for any reason.
|
Designator
|
Original
value
|
New
value
|
h/k
part number
|
|
R223
|
51kOhm
|
30kOhm
|
110-16303J26
|
|
R224
|
51kOhm
|
30kOhm
|
|
|
R226
|
27kOhm
|
10kOhm
|
110-16103j26
|
|
R227
|
27kOhm
|
12kOhm
|
110-16123j26
|
