Kenwood GE-940 User manual

GEo40
KENWOOD
SERVICE MANUAL
© 1990-7 PRINTED IN JAPAN
B51-4206-00 (O) 1953
Metallic cabinet Front glass Sub panel assy Panel
(A01-1876-01) (B10-1826-03) (A22-1431-02) ({A20-6096-02)
Foot
Knob
Knob
(JO2-1040-05)
x
2
(K29-3991-03)
(K29-3992-04)
AC
power
cord*
AC
outlet*
(E30-)
(E03-)
4
Ges
aa
ane
PS
sss
loo}
Lam’
ae
nll
oy
fs
Ge
Xf
r
0
(ho
A
0
()
h-——)
ayev
Foot
Phono
jack
Rectangular
receptacle
=
Slide
switch*
(J02-0370-05)
x
2
(E13-0446-05)
{E08-0312-05)
(S31-2131-05)
* Refer to parts list on page 24.

GE-940
CONTENTS / ACCESSORIES
Contents
ACCESSORIES tsi sAeccirn dann terkiitaasan 2 7. Display Microprocessor : M50747-D60SP (IC5).. 9
CIRCUIT DESCRIPTION 8. Display Tube Driving Condition ................... 11
1. Microprocessor Block Diagram and Key Matrix .. 3 PC BOARD (COMPONENT SIDE VIEW) ................ 12
2. Main Microprocessor : M509045-061SP (IC6) ..... 4 SCHEMATIC DIAGRAM .............:cccccsccssseesssseesseerees 15
3. Data of MEMORY EQ CURVE .............0..ce 6 EXPLODED VIEW ..........c:cccsssccssssssssscssssscssseeseneeeees 23
A TEST (MODE ssvieoscsscstcsscacecnvecoousosteudacsbecbucteccvsucocesse 7 PARTS HIST ‘iicsiasosssecdsciscicsdacdactasssesesecssia ce veettenesesdecses 24
5. Explanation of Operation of Al LINK............... 7 SPECIFICATIONS ........::.::cccccesessssecseeeres BACK COVER
6. Tranesfer Method...........ccccccccscsssesssesseesseseeseees 8
Accessories
AC plug adaptor ........... 1
(Except for some areas)
For the unit with a European AC
plug in areas other than Europe.
(E03-0115-05) (E30-0505-05)
System control cord .... 1
eb \
i e
(E30-2628-05} ts

GE-940
CIRCUIT DESCRIPTION
1. Microprocessor Block Diagram and Key Matrix
1C27 1C6
Cii4— 75
HR Trae | i
| f10-—4 4051 | 1}
XR 1091 | £8 -—4
£§ > -
I
‘
ies
81
—
r
-
£5 1) [ING
xR-1091 | ff —————- =
a ‘INO
£13
La Pa |
"(Pad |
| N50945
eT ‘paz rn Conran
|
NJU7305
3/
P10
POO}
ye,
)
FL:
,
|
Display
tube
| GE IC as 66 Liver —szouent |
=< P40 P16 POT] | cseaxenn ‘BL~BI5
Pane a i 4
'u50747-g0sPp——3)-
P37
Peo
i
FLL
oy
ica
|
Display pew fo s ; 7 Driver! Ti g~ 678 |
-
2
(P33
P26
|
crt)
_|
ie
cy perce ae 2 jP32 f ot
SYNC = TP31 PLT}
anne Sa § j=} KEY MATRIX
: eset rae i f iP30 P27
| CE -——- fy
on | / "RESET RO
| | /
|___RESET eee. 5 pe KEY RETURN
[Ose lator — Kin R3 |
— same Xout a 7
4. OMHz
_———SSs |
KROQ KR1
ROCK JAZZ
CAR ST, HP. ST.
M
1
R
{
L
Gd
POPULAR 7
DFULAR | RUSTON
DISPLAY CHARACTER
PLAT MEMORY
RO
37
AUREX/
ROXY
R
36
KR2
WIDE/
NARROW
GRAPHIC/
PARAMETRIC
KR 3 KR4
m= | — |
G5 G6 AT MANUAL
CLASSIC MOVIE PATTERN
po PAUSE EQ EFFECT
CONCEPT / OTHERS/
ROXY JTYPE
R2 R3
34
P2,
35 55

GE-940
CIRCUIT DESCRIPTION
2. Main Microprocessor : M50945-061SP (X14-2930-00 : IC6)
2-1. Terminal connection diagram
pon ae |
Reference voltage input Vrer [Li 164] Vee
XR-1091—>TC74HC4051 a) bal
2,4,6,8,10,12,14 2 63 AVec
“Rg >| 3) 62 KSO GIB) KEY MATRIX
Fi >| 4| lei) KSI Gap | (KEY SCAND
jr [5 60| <> KS2 G3B
XR-1091 =a Display tube
LR [6 59 KS3 G4B °
BAND PASS FILTER = GRID
PB [7 58] <> KS4 G5B
Fy | 8| 571 <> KS5 CBB
A [9 56] <+ KS6 G7B
mal tee] ., KR4 KEY MATRIX
D
=
{101
59
(KEY
RETURN)
TCTAHC4051
|
C
J)
54
B15
ae | B <{12| o 53) —> Bd
O t——
“A +(1 = [52] > BS
Ne + (14 o [51] > BI
ce ve | UAT 15 © 50} B2 |
crock = {16 re) 49] > BLO
NIUTIO5
|
7
aa
Sis
7
;
ara
LO
ras)
Display
tube
| SYNC 'y = 47 Bll >
ort -— segment
Display
|
EHOtS
(19)
Bu
‘a
microprocessor < DATA {20| 145} B7
450747-D60SP | BUSY al Ma} > BB
(READY — [221 43) > B3
Serial {S$ DATA + [23] 42] B14
input/output be S BUSY [24 41] B12
CE
-
{25
40]
~
B13
J
xq) _. KSINI KEYMATRIX
eve, 31) ea (KEY SCAN)
Reset input RESET at 38 (Vp) Vss
Clock input Xin 28) 137| KROQ
Clock output Xour + [29] 36] RI | KEY MATRIX
Vss
(Xen)
—
[30
[35]
—
kR2
(
(KEY
RETURN)
NC (Xcour) 31 | 134 KR3 |
ea 34)
Vss 32) 133} (¢ NC

GE-940
CIRCUIT DESCRIPTION
2-2. Description of terminals
Pin No. Pin Name 1/0 Name Description
VREF — | VREF Reference voltage input: for A/D converter.
2 7 | F8~F14 Analog signal input for 1kKHz~16kHz and AMP VR position detection.
AMP VR (For inputting signal coming in by way of Multiplexer TC74HC4051 )
3 IN6 F6 10kHz analog signal input. (For inputting signals coming in directly from filter circuit.)
4 N6 F5 3.9kHz analog signal input. (For inputting signals coming in directly from filter circuit.)
5 6 | | F4 1.5kHz analog signal input. (For inputting signals coming in directly from filter circuit.)
6 IN6 V4 F3 625Hz analog signal input. (For inputting signals coming in directly from filter circuit.)
7 IN6 F2 250Hz analog signal input. (For inputting signals coming in directly from filter circuit.)
8 6 | F 98Hz analog signal input. (For inputting signals coming in directly from filter circuit.)
9 IN6 | FO 40Hz analog signal input. (For inputting signals coming in directly from filter circuit.)
10~13 | P47~P44 O | D-~A Control signal output for Multiplexer TC74HC4051.
14 P43 O |} NC Unused.
15 | P42 O | DATA Output of NJU7305 CONTROL DATA signals for electronic VR of graphic equalizer.
16 P41 O | CLOCK Output of NJU7305 CONTROL CLOCK signals for electronic VR of graphic equalizer.
pod? P40 O | ST Output of NJU7305 CONTROL ST signals for electronic VR of graphic equalizer.
18 P37 | | SYNC | Input for transfer display data indication signals.
| H: DISPLAY MODE data L: LEVEL or POINT data
19 P36 (CLK) O | CLOCK CLOCK signa! output for DISPLAY data transfer.
20 P35 (Sout) O |} DATA DATA signal output for display.
21 P34 O | BUSY Output for DISPLAY DATA TRANSFERRING signals. H : Data transferring L: Others
22 P33 READY Input for DISPLAY DATA TRANSFERRABLE signal. H : Not transferrable L : Transferrable
23 P32 VO | SDATA Input/Output for SYSTEM SERIAL DATA signal.
24 P31 VO | SBUSY Input/Output for SYSTEM SERIAL BUSY signal.
25 P30 CE BACK UP detection. H : Others L : Backing up
26 CNVss - | Vss Unused.
27 RESET RESET RESET signal detection. H : Others L: Reset
28 XIN XIN System clock input (4.0MHz).
29 XOUT O | Xout System clock output.
30 XCIN Vss Unused. (Clock input terminal for timer.)
31 XcOuT | O | NC Unused. (Clock output terminal for timer.)
32 VSS - GND.
33 ra) O |} NC Unused. (Output terminal for system clock 1/4 divided frequencies.)
34~37 | R3~RO | | R3~RO KEY RETURN signal input.
38 Ve - | Vss Pull down input.
39 P17 O | KSINI Destination switch SCAN output. H: Reset L : Normal
40~54 | P16~P00 O | B1~B15 Output for DISPLAY TUBE SEGMENT DRIVE. H : OFF L:ON
55 P27 | | KR4 KEY RETURN signal input. H: OFF L:ON
56~62 | P26~P20 O | KS6~KSO KEY SCAN signal. Output for DISPLAY TUBE GRID DRIVE. H : OFF L: ON
63 AVcc — | AVcc Power supply for A/D converter (+5V).
64 Vcc t= Vec Power supply for microprocessor (+5V).

GE-940
CIRCUIT DESCRIPTION
3.Data of MEMORY EQ CURVE
(1) REFERENCE x5
SOFT
CLEAR
HEAVY
SCALE
NR
(2) REFERENCEIL x5 (Double-speed REC curve)
SO
(3) MANUAL X5 = (RESET curve at initialized)
DSP PRESENCE MODE ARENA : POPULAR or ROCK CONCERT
DSP PRESENCE MODE STADIUM : POPULAR or ROCK CONCERT
ae
PRESENCE
MODE
ARENA
or
STADIUM
or
CHURCH
:
CLASSIC
CONCERT
HEAD PHONE STEREO
(4) AI AUTO x25
(I) shy LI-Hl (I) ee aw (I) ae :L3-H1 (IV) 16(f) :L4-Hl
2 (2) :L1-H2 7 (7) :L2-H2 12 (b) :L3-H2 17 (g) :L4-H2
3(3)
:L1-H3
te
L2-H3
13
(c)
:L3-H3
18
(h)
:
L4-H3
4(4) :L1-H4 9 (9) :L2-H4 14 (d) :L3-H4 19 (i) :L4-H4
5 (5) :L1-H5 10 (0) :L2-H5 15 (e) :L3-H5 20 (j) :L4-H5
(5) AI MANUAL 6x5
(1) POPULAR (IL) ROCK (II) JAZZ
SOFT SOFT SOFT
CLEAR CLEAR CLEAR
BASIS BASIS BASIS
SCALE]
(HEAVY)
SCALE]
(HEAVY)
SCALE]
(HEAVY)
SCALE2 SCALEZ SCALE2
(IV) CLASSIC (V)FUSION (VD MOVIE
SOFT SOFT SOFT
CLEAR CLEAR CLEAR
BASIS BASIS BASIS
SCALE]
(HEAVY)
SCALE]
(HEAVY)
SCALE]
(HEAVY)
SCALE2 SCALE2 SCALE2
(6) AI LINK x6
ARENA
JAZZ CLUB
STADIUM
DISCO
CHURCH
MOVIE
(7) AI TIMER] x2
STEP1
STEP2
(V) 21 (k):L5-H1
22 (1) :L5-H2
25 (0) :L5-H5

GE-940
CIRCUIT DESCRIPTION
4. Test Mode
4-1. Test mode with key switch
* Setting method
1. Press the M/R key switch, connect the AC plug to
an outlet.
2. Pressing the FLAT key switch, connect the AC plug
to an outlet.
* Contents of operation
1-1. If the test mode is selected, the short check of the
segment terminals is indicated. If any key switch is
pressed, the device returns to the normal indica-
tion but it is kept in the test mode.
1-2. If the short check of the segment terminals is indi-
cated, the bars of all the bands light up by five
segments, and the lighting bars move up at the
interval of 256msec. The 14-segment indicator and
mode indicator on the right continue lighting in
order of B15, B4, B5, B1, B2, B10, B9, B11, B6, B7,
B8, B3, B14, B12, B13, B15, B4 ...
1-3.1f the Al MANUAL key switch is pressed,
"Al MANU" is indicated, then the device goes to
the genre section mode without performing sam-
pling operation.
1-4.Set the contents of the MANUAL PRESET MEM-
ORY as follows.
M1: FLAT (ALL OdB)
M2 : ALL MAX (ALL +12dB)
M3 : ALL MIN (ALL -12dB)
1-5.The EQ LEVEL UP/DOWN operation is set to
three points of +12dB, OdB, and -12dB at all the
frequencies.
.If the test mode is selected, all the indicator lamps
light up.
2-
pa
4-2. Resetting method of test mode and initialization
In either the key switch test mode or the serial test
mode, if the AC plug is disconnected from the outlet
and connected again to the outlet, the microprocessor
is initialized and the power is turned off. At the same
time, the test mode is reset.
5. Explanation of Operation of Al LINK
5-1. Bar indicator
After Al LINK" is indicated for four seconds, the
device returns to the last indication. If the
DSP PRESENCE MODE is turned off, the PRE-
SENCE MODE curve is indicated and the device re-
turns to the last indication.
5-2. 14-seg. indicator
“DSP PRESENCE MODE" is indicated.
5-3. Mode indicator
When AI LINK is turned on :
The mode indicator normally lights up.
If the code of DSP PRESENCE MODE is received
during the Al TIMER 1, CCRS, REC, Al AUTO, or
A! MANUAL operation, the mode indicator flashes.
It lights up when the Al TIMER 1, CCRS, DEMO,
REC, Al AUTO, and Al MANUAL operation is com-
pleted.
While Al LINK is turned on :
The same indication as the time when the Al LINK is
turned on is performed.
While Al LINK is turned off :
The mode indicator goes off.
5-4. Operation
If the DSP PRESENCE code is sent from AMP while
the Al LINK is turned on and if the required presence
mode is different from the present one, the EQ curve
for the mode of the sent code is called up. In case of
the DSP OFF code, however, the EQ curve just before
entering the Al LINK mode is called up.
lf DSP PRESENCE code is received during the
AIL TIMER 1, CCRS, DEMO, REC, Al AUTO, or
Al MANUAL operation, the EQ curve of the DSP
PRESENCE mode is not called up immediately, but
called up after the operation has been completed. At
this time, the Al LINK indicator (MODE indicator) con-
tinue flashing after the DSO PRESENCE code is re-
ceived until the EQ curve is called up.
If the Al LINK is turned off, the device returns to the
last indication without changing the EQ curve.
If the Al LINK switch is pressed, the Al LINK is
turned on and off alternately.
If the EQ curve is changed in the Al LINK mode
(including the case that the f UP/DOWN switch is
pressed), the Al LINK mode is turned off.
lf the Al AUTO switch is pressed when the
Al AUTO indication is turned off in the Al LINK mode,
or if the Al MANUAL switch is pressed when the
Al MANUAL indication is turned off, the curve just be-
fore the Al LINK mode was selected is called up and
the Al LINK mode is turned off.
The Al LINK mode is backed up.
DSP PRESENCE mode
0 : DSP OFF 3: STADIUM
1:
ARENA
4:
DISCO
2:JAZZCLUB
5
:CHURCH
6
:
MOVIE

GE-940
CIRCUIT DESCRIPTION
6. Transfer Method
Data are transferred by the unit of 8-bits in the
LSB first mode.
° SYNC is raised at the header to clearly show the di-
visions of the transferred data (including the
header).
e READY is raised at the head of each 8-bit datum to
clearly shows each division of the data.
© lf any mistake is made in the transfer of data, the
highest priority is given to SYNC to modify the syn-
chronization of data.
Data are taken in at the rise of the clock.
BUSY is raised when data are transferred.
Transfer is started when READY is raised.
DATA are sent with LSB at head.
6-2. Transfer method
First,
the
display
microprocessor
notifies
the
trans-
mission
of
the
header
to
the
main
microprocessor
by
setting
SYNC
to
''H"’.
Then,
it
set
READY
to
"'L"
to
notify
that
it
can
receive
data.
When
the
READY
is
set
to
'"'L'',
the
main
micropro-
cessor
checks
SYNC.
If
SYNC
is
"'H'",
the
main
micro-
processor
sends
the
header
signal
to
the
displayr
mi-
croprocessor
(READY
returns
to
''H"
at
the
first
rise
of
the
clock),
If
the
display
microprocessor
receives
an
8-bit
data
and
confirms
that
it
is
a
header,
it
turns
SYNC
to
"L"
and
also
turns
READY
to
"'L"'
again,
then
demands
the
data
from
the
main
microprocessor.
6-1. Connection
Main
microprocessor
Display
microprocessor
SYNC = _20PIN
READY 18PIN
20 DATA 21PIN
19 CLOCK 19PIN
21 BUSY 22PIN
SYNC
J
ee
eee
READY
SF
=<
DATA 8-bit DATA
clock —SFU UE AAA
Busy ____J L__J S255
+ ____+
Header section
Saar raeaa
Data section

CIRCUIT DESCRIPTION
7. Display Microprocessor : M50747-D60SP (X14-2930-00 : IC5)
7-1. Terminal connection diagram
Vee COV)
Segment A8
Segment A7
Segment A§
Segment A5
Segment A4
Segment A3
Segment A2
Segment Al
Grid 6
Grid 5
Grid 4
Grid 3
Grid 2
Grid ]
Segment A5Q
Segment AQ5
RDY
CLK
SYNC
DATA
BUSY
CE
Latch output
Segment C3
CE
CNVss
Reset input RESET
Clock input Xin
Clock output Xout
Timing output ¢
Vss COV)
t
f a
i 64]
= =
2 \63}
3 62) >
I
|
61|
ra =
5 60]
6. 59| >
— =
7 158] >
[ 8| 57] +
L9| 56) >
10) 55] o
=
iL 54] <>
ay = Ol +
13 ina 52) +
4) [51] >
15 a 50] >
[26] | [49} <>
17) ~ [48] +
[18 | 47>
ca st so
i i Ao) ~
20! 45| >
=a ome) Eas
[21 44)
= je
22 ae 13)
2
=
12]
(24 [41] +
25) 40) -
[26] 39] <
(27 [38] =
aa a1 ~
29) (36) =
(30| 135]
31 3a] -
32, 33) -
P20
P21
P22
P23
P24
P25
P26
P27
P0o
P01
PQe
PQs
P04
POs
POs
P07
Plo
Pli
Pls
Pl
Pls
Ple
Ply
Pdo
Po
Pde
POs
PSs
Pds
Pde
Po7
Grid 7
Grid 8
Grid 9
Grid 10
Grid 11
Grid 12
Grid 13
Grid 14
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Display
GND
GND
GN
GN
G
G
G
Uo ©
ND
ND
ND
GE-940 GE-940
inverter input
7-2. Description of terminals
Pin No.| Pin name Name
CIRCUIT
DESCRIPTION
Description
Pin name
‘|
os
™~
oO
Description
oY
Voc
+
Power supply
33 POT
+4.
POT
GND
4
Segment A8
Segment
34
P56 P96
GND
t
Segment A7
ani
Segment
39
P59
Po
GND
Oo;}o!;1ot;=—
Segment A6
Segment
36
t
Pod
Po4
Segment
Segment
Segment
Segment
37 POS P53 GND
Segment
38
PO2
PO2
GND
Segment
39
Pol
| Pol
GND
Segment
Segment
40
P50
Invert
Display invert input
Grid 6
Segment
4] PIT
Segment
Segment Al |
Grid
42
P16
Segment
=
Segment
~
Segment
Grid 5
Grid
43
P15
| Segment
Segment
Grid 4
Grid
44 Pl4
Segment
| See
Grid 3
Grid
45
P13
Segment
Segment
Segment
Grid 2
Grid
46
Segment
Segment
Grid |
47
Pll
| Segnent
Segment
HH |H|o
LATCH OUT
| :
Segment A50 | Segment
Serial CLK
Serial SYNC
Serial DATA
Serial BUSY
Chip inable
7T4HC77 latch control
Segment C3
Fgacnent
48
P10
t
SIlOoOlol oa] Ol] OG] OES | ad atm tet ee]
Segment
Segment A1[6
Segment A15
Segment Al4
Segment A13
Segment Al2
OoO;o;o;yo;o;];o
Segment Al
Segment A10
Segment AQ”
o!1o
T
Segment
Segment
Segment
Segment
Segment
Segment
Segment
Segment
CE
Chip inable
| CNss
GND
RESET
RESET
Xin
Clock
Ole lel Rel olo
Xour
Clock
Timing signal ¢ output
el
COLO} ol} o};]o;o;o|o
10

GE-940
CIRCUIT DESCRIPTION
8. Display Tube Driving Condition
Display y-conm uPA8OC
Grid 1~14 |] Pin 10~15, 57~64
Segment | Segment 1~24
1/0
Segment
24
Segment
26~49
Latch
Segment 25
Segment 50