Boss GT-1, Service Notes

Page: 19 / 29

19
Sep. 2016 GT-1
8. INTERNAL EXP1 (CALIBRATION)
This performs calibration for the pedal of the unit.
1.
In the TEST MENU , select 8. INTERNAL EXP1 and press ENTER .
2.
Depress the heel side of the pedal all the way and press MENU .
The minimum value offset is saved to the unit.
3.
Depress the toe side of the pedal all the way and press
MENU
.
The maximum value offset is saved to the unit.
4.
Forcefully depress the toe.
The
PEDAL FX
LED next to the pedal lights up.
5.
Forcefully depress the toe again.
The LED goes dark.
6.
Press EXIT to return to the TEST MENU .
9. CTL
This verifies the operation of the CTL2,3/EXP2 jack.
1.
Connect the foot switch (FS-5U x 2, or FS-6 x 1) to the CTL2,3/EXP2 jack.
2.
In the TEST MENU , select 9. CTL and press ENTER .
3.
While depressing the foot switch connected to the tip side, verify that
[CTL1] on the screen is displayed as ON .
4.
While depressing the foot switch connected to the ring side, verify that
[CTL2] on the screen is displayed as ON .
5.
Detach the foot switch.
6.
Press EXIT to return to the TEST MENU .
10. EXT EXP2
This verifies the operation for the expression of the CTL2,3/EXP2 jack.
1.
Connect the expression pedal (EV-5) to the CTL2,3/EXP2 jack (TRS).
2.
In the TEST MENU , select 10. EXT EXP2 and press ENTER .
3.
Depress the heel side of the expression pedal all the way and verify that
the value of
[EXP] displayed on the screen is 4 or less.
4.
In the same way, depress the toe side of the expression pedal all the way
and verify that the value displayed on the screen is
630 or higher.
5.
Detach the expression pedal.
6.
Press EXIT to return to the TEST MENU .
* Ignore the display of
AD SW.
11. AUDIO SELF
This item is not required at the service.
12. NOISE
This measures residual noise.
1.
Connect the 1/4-inch mono phone plug with 47 kΩ load resistor to the
INPUT jack and enter the Test Mode.
2.
In the TEST MENU , select 12. NOISE and press ENTER .
3.
Connect the amp-equipped monitor speakers to the OUTPUT L/MONO
and R jacks.
4.
Drop the unit from a height of about 5 centimeters and verify that no
abnormal noise is produced.
5.
Disconnect the amp-equipped monitor speakers and connect the noise
meter to the
OUTPUT L/MONO and R jacks.
6.
Verify that the residual noises are as the following values.
OUTPUT L: -60 dBm or less (DIN-Audio)
OUTPUT R: -60 dBm or less (DIN-Audio)
7.
Detach the noise meter.
8.
Connect the amp-equipped monitor speakers to the PHONES jack (L, R).
9.
Drop the unit from a height of about 5 centimeters and verify that no
abnormal noise is produced.
10.
Disconnect the amp-equipped monitor speakers and connect the noise
meter to the
OUTPUT L/MONO and R jacks.
11.
Verify that the residual noises are as the following values.
OUTPUT L: -60 dBm or less (DIN-Audio)
OUTPUT R: -60 dBm or less (DIN-Audio)
12.
Detach the noise meter.
13.
Press EXIT to return to the TEST MENU .
13. AUDIO OUTPUT
This item is not required at the service.
14. AUDIO INPUT
This verifies the input and output of the audio signal.
Input Test
1.
Connect the signal generator to the INPUT jack and the unit enters the
Test Mode.
2.
In the TEST MENU , select 14. AUDIO INPUT and press ENTER .
3.
Connect the oscilloscope to the OUTPUT L/MONO and R jacks.
4.
Input a signal like the following to the INPUT jack.
INPUT: 200-Hz sine wave at 5.0 Vpp
5.
Turn the knob
1
to set the value shown in the figure below to
0AE
.
fig.test-14-1.eps
6.
Verify that signals like the following are output from the
OUTPUT L/
MONO
and
R
jacks
OUTPUT L: 200-Hz sine wave at 4.8 to 5.4 Vpp
OUTPUT R: 200-Hz sine wave at 4.8 to 5.4 Vpp
7.
Change the connection of the oscilloscope to the
PHONES
jack and verify
that signals like the following are output.
PHONES L: 200-Hz sine wave at 4.8 to 5.4 Vpp
PHONES R: 200-Hz sine wave at 4.8 to 5.4 Vpp