Akai AM U07 Schematic

Page 1

V. DESCRIPTION OF CIRCUIT

5-1 FADER

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e==
C
SW7 q
TRZ
ro ic2 J;
tremors?) ' ,
I
lCl Pm @ i
l
l
I.-
lCl PIN I
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I
POWER 0N
Fig. 5-1

(0

When the tactile switch (SW7) is pushed, the 1C1
(TC9130P) input pin (9 will detect falling edges, and
the 1C] (TC9l30P)'output pin (9 will repeat attaining
L" and H" levels alternately.

With the fader on", the ICl (TC9130P) output pin ®
will attain an L level and the [C2 (TC4001BP) pin (3

SERVICE MANUAL AM-U7

output an H" level, as a result of which TR3 will turn
on and the fade-out indicator lamp (IN903) light up.
With the fader of , since the lCl (TC9l30P) output
pin (D is at an H" level, TR3 will turn off and TR2 on,
as a result of which the fade-in indicator lamp (1N902)
will light up.

Page 2

5-2 FADE IN AND FADE OUT

FROM lct TCSIBOP
PING

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2 9 2/4 I

an a .

6
ICZ TC4OOIBP

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VOLUME PCB

MAIN AMP PCB

Fig. 5-2

FABgR SW 0N"

FADER SW "OFF"
|

5
N
3
z

1) FADE IN

When an H" level is output by [C] (TC9130P) pin
(D, [C2 ('l'C400lBP) pin (4) will attain an L level,
after which ICZ (TC400lBP) pin ® will attain an
L level, and lastly, lC2 (TC4OOIBP) pin CD will
attain an L level. C11 and C21 will then slowly
discharge, drawing the TR14 and TRIS gates toward
-B, and RM and TRIS will slowly turn off.

2) FADE our

SERVICE MANUAL AM-U7

When an L" level is output by [Cl (TC9130P) pin
(D, 1C2 (TC4OOIBP) pins @ and (I) will attain H"
levels, slowly raising the TRM and TRIS gate volt-
ages, and ultimately 1C2 (TC4OOIBP) pin ® will
attain an H" level, at which time, the TRl4 and
TR] 5 voltages will reach the levels set in advance.