Roland JUNO-106 - Noise Level and PWM Adjustments; Chorus Bias and Load Offset; MIDI Function Switch Check; Board Diagrams and Layouts

JUL. 31, 1984 JUNO-106
TPT TP2
a MODULE BOARD VRNO. 28 23 18 13 8 3 JACK BOARD
TP?1
1P3
CH
NO.
1
2
3
4
5
6
ee + anatog Ground Analog Ground
NOTE: Procedures 7 and 8 interact. Repeat the steps in
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alt nee ANG Be, oR 8 BS ae Et te ead areas | 9, NOISE LEVEL
z wos A) GF 2f0) Or 3 | Or [kd] ga 3 i (MODULE BOARD)
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“PPS:
BOR
ae
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CAUTION
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4
Test
instrument:
Oscilloscope
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Beet
Eat
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Test
point:
TP8
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/II\\\ WAY oe "2 2 f= ; A Key assignment: POLY 1
TP19
(CHT)
BANK:
6
TPB
TP13
TPI@(CH2)
Digital
Ground
11.
CHORUS
BIAS
(CH1) (CHB) : 2 ’
TP14 7 nes elena TP15 TP16 TPI7 TPI8 TPI9 TPT] TP4 TP6 TPS 9-1. Holding any key on the keyboard down, adjust (JACK BOARD)
(CH2} (CH5} TP15(CHS) Not provided on early PCBs: Connect to the hot VR32 for 4Vp-p on the scope.
ee hale TP14(CH6) terminal of trimmers defined as TP14—TP19. Test instrument: Oscilloscope, Audio generator
Test point: TPi (CH1), TP2 (CH2)
VCA LEVEL: 0
KEY DESIGNATION VRNO. 27 22 17 12 7 2 CHORUS: |
Tw) CH NO. 1 2 3 4 5 6
11-1. Feed 10Vp-p, 1kHz, sine wave into TP2 of the
ith
Ik
7.
VCF
FREQUENCY
10.
PWM
MODULE
BOARD.
(MODULE
BOARD)
(MODULE
BOARD)
11-2.
Adjust
VR1
(CH1)
and
VR2
(CH2)
on
the
JACK
c ch Ok ns 8 <7 SAUTION a . Se eae
i This adjustment must be performed after 10-minute 2. DCO CV OFFSET must have been finished. harvental ie aR eae es
442Hz
warmup
has
passed,
(o]
.
MOGULECOMEE)
Test
instrument:
Frequency
counter
or
Tuner
Test
instrument:
Oscilloscope
Test point: TPS (CH1) to TP13 (CH6), or Test point: TP8 (CH1) to TP13 (CH6)
CAUTION OUTPUT Key assignment: POLY 1
Key assignment: POLY 1 (UNISON during test BANK: 5
This adjustment must be done after 10 minutes has pass-
ed and after 3. VCA BIAS has been finished.
mode) or POLY 1 + POLY 2
(ROTARY during test mode) --
10-1..While holding C4 key down, adjust VR31 for a
Properly adjusted
Test instrument: Oscilloscope when checking at OUTPUT 50% duty cycle.
Test point: TP19 (CH1) to TP14 (CH6) BANK: 3 ee 12, LOAD OFFSET
Key assignment: POLY 1 {UNISON during test (JACK BOARD)
mode). 7-1. While holding C4 key, adjust the trimmers listed Test instrument: | Voltmeter with 1mV resolution
BANK: 3 below, respectively, for 248Hz (B3 pitch). Tolerance: 48-52% Test point: TPS
5-1, While holding down C4 key, adjust the trimmers
listed below, respectively, for 4.8Vp-p sine wave.
VRNO. 26 21 16 11 6 1
VRNO. 29 24 19 14 9 4
CH NO, 1 2 3 4 5 6
8. VCF WIDTH
(MODULE BOARD)
10-2. Confirm that the duty cycles of the rest channels
(TPQ ~ TP13) are within 48 — 52%.
12-1. Adjust VR3 for OmV reading.
13. MIDI FUNCTION SWITCH CHECK
13-1. Verify the following with FUNCTION set at res-
CH NO. 1 2 3 4 5 6 ; ne
CAUTION pective position.
6. VCA GAIN ;
°
Perform
this
adjustment
after
at
least
10-minute
warm-
I:
only
VERIFY
LED
lights
(MODULE BOARD) up 10-3. Holding C4 key down, confirm that duty cycle of . :
: ae ae Tl: only SAVE LED lights
CAUTION
;
all
channels
are
within
93
—
97%
with
PWM
set
at
10.
I:
LEDs
liaht
fore.
Test
instrument:
Frequency
counter
or
Tuner
>
ho
Siig
This
adjustment
must
follow
5.
VCF
RESONANCE.
Test
point:
TP8
(CHI)
to
TP13
(CH6),
or
NOTE:
If,
incidentally,
the
PWM
knob
has
been
set
at
OUTPUT (tuner method)
Test
instrument:
Oscilloscope
Key
assignment:
POLY
1
or
POLY
1
+
POLY
2
Test
point:
TP8
(CH1)
to
TP13
(CH6)
(OUTPUT)
Key
assignment:
POLY
1
(UNISON
during
test
BANK:
3
mode}
BANK:
3
6-1. While holding down C4 key, adjust the following
trimmers, respectively, for 6Vp-p sinewave.
8-1.
Holding
C6
key
down,
adjust
each
trimmer
listed
below
respectively
for
992Hz
(equal
to
BS
note).
10, lower it then raise to 10 again.
19