9
May. 2000
DB-700
LED
MANUAL
A
B
WRITE
4 Controls
The LEDs shown right indicate the test number.
Test No.4
Press the WRITE button when skipping this test. Otherwise,
press the MANUAL button to start the test.
4.1 Rotate the AMPLIFIER TYPE (rotary switch) knob
from SOLID STATE to TUBE and then to TUBE
DRIVE. Observe the following LEDs that should light
to show the switch position.
When all switch positions are read, the POWER
INJECTION LED lights in green.
Press the WRITE button or depress the A/B foot
switch to proceed to the next test step.
4.2 Start with the leftmost control.
Potentiometer: from full-counterclockwise (FCCW)
position to full-clockwise (FCW) position
As the knob travels, the LED corresponding to the
scale will light:
(These values are just as a guide.)
When all travel ranges of the potentiometer has been
sensed, the POWER INJECTION LED lights in green.
The unlit LED is a sign of NG.
Press the WRITE button or depress the A/B foot
switch to proceed to the next control test.
When the next item to be test is a potentiometer,
repeat the step.
SHAPE switch: turn it on and then off. The green
POWER INJECTION LED indicates that the switch's
on and off states are correctly detected.
Turn on CHORUS switch and verify lighting CHORUS
LED. Then, test the potentionmeter.
PHONES socket: insert the standard plug into the
socket and then withdraw.
The POWER INJECTION LED lights in green
indicating that open/close of socket contacts are
correctly detected.
Press the WRITE button to proceed to the next test.
Switch position
LED
SOLID STATE
MANUAL
TUBE
A
TUBE DRIVE
B
Scale
LED
0-4
MANUAL
4-6
A
6-10
B
LED
MANUAL
A
B
WRITE
5 DSP
The LEDs shown right indicate the test number.
Test No.5
Press the MANUL button.
The bus between the DSP and DRAM is tested.
The POWER INJECTION LED lights in green when the bus
is intact.
The POWER INJECTION LED lights in red to show NG
bus.
Remove the foot switches.
This completes the test. When proceed to "Loading factory
presets" shown below, press the WRITE button. Otherwise,
turn off the POWER switch.
6 Loading factory presets
When this procedure is following the test 5 above, the
LEDs A, B and WRITE are blinking (standby). Press the
WRITE button to start loading.
While loading, the WRITE LED blinks and at the end of
loading the LED A will light.
Turn off the POWER switch.
CAUTION:The following procedure will erase user data.
♦
Checking input/output level, noise level and
power limiter
Connect 8
Ω
load to speaker out WOOFER and TWEETER.
To check power limiter, connect a 680
Ω
load to the hot and
cold terminal of LINE OUT BALANCED socket, respectively.
1. Entering the checking mode
1.1 Set AMPLIFIER TYPE switch to SOLID STATE.
1.2 Set MASTER knob to 10.
1.3 Set GND LIFT switch to OFF.
1.4 While pressing MANUAL and WRITE buttons, turn on
POWER switch.
1.5 LEDs "A" and "B" light. Press MANUAL button and the
LEDs turn off. Now the unit is in the checking mode.
2. Checking input and output levels
2.1 Set the following controls:
AMPLIFIER TYPE switch: SOLID STATE
MASTER knob: 10
Other controls: Don't care
2.2 Check input and output levels:
Apply 1 kHz, sine wave signal to INPUT. Check level
at various points by referring to the corresponding
level denoted on the circuit diagram.
3. Checking noise level
3.1 Set the following controls:
AMPLIFIER TYPE switch: TUBE
MASTER knob: 10
Other controls: Don't care
3.2 Check noise levels:
Leave INPUT sockets disconnected.
3.2.1 With panel settings as mentioned 3.1 above:
Measuring point: Speaker output WOOFER (8
Ω
)
Noise level:
−
32.0 dBm (IHF-A)
