Gemini Sound BPM-1 Service manual

SERVICE MANUAL

BPM-1

PROFESSIONAL AUTOMATIC BEAT COUNTER

CONTENT’S:

Connections & Operations:.......................................................Page 2-3

Specifications:..............................................................................Page 3

Parts Lists:.................................................................................Page 3-4

PCBs:..........................................................................................Page 5-6

Schematics:..................................................................................Page 7

Gemini Sound Products Corp.

120 Clover Place P.O. Box 6928

Edison, NJ 08818-6928

732-738-9003 (Phone) • 732-738-9006 (Fax)

Page 1

21

20

19

11

10

8

7

5

4

2

1

11

10

8

7

5

4

2

1

12

9

6

3

18

17

16

15

14

13

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Connections

1. Make sure that the POWER (13) switch is in the off position. The
POWER LED (14) will be off. This unit comes supplied with a 15 volt

AC adaptor. Plug the adaptor into the rear panel power jack. Then plug
the adaptor into a proper power source.

2. Use the 4 stereo PHONO/LINE (2, 5, 8, 11) inputs on the rear panel to
connect to the output of your sources. The PH1/LN1 (12) switch
enables you to set the CHANNEL 1 (11) input sensitivity to Phono or
Line. The PH2/LN2 (9) switch enables you to set the CHANNEL 2 (8)
input sensitivity to Phono or Line. The PH3/LN3 (6) switch enables you
to set the CHANNEL 3 (5) input sensitivity to Phono or Line. The PH4/
LN4 (3) switch enables you to set the CHANNEL 4 (2) input sensitivity
to Phono or Line. Note: When using turntables, don’t forget to connect
the ground wire from your tuntable to the ground screw of your mixer.

3. The BPM-1 is supplied with 4 sets of OUTPUT (1, 4, 7, 10) jacks. If you
are using a turntable and have the input set to phono, the
corresponding output must be connected to phono inputs on your
mixer. If you have the input set to line, the corresponding output must
be connected to line inputs on your mixer. Use the CHANNEL 1
OUTPUT (10) jacks to connect to the appropriate inputs on your mixer.
Use the CHANNEL 2 OUTPUT (7) jacks to connect to the appropriate
inputs on your mixer. Use the CHANNEL 3 OUTPUT (4) jacks to
connect to the appropriate inputs on your mixer. Use the CHANNEL 4

OUTPUT (1) jacks to connect to the appropriate inputs on your mixer.

Operation

1. POWER ON: Once you have made all the equipment connections, press
POWER (13). The power will turn on and the POWER LED (14) will
glow RED. When you turn on the BPM-1, the unit will run through an
initialization period in which the BPM DISPLAYS (17, 19) and the BEAT
OFFSET INDICATORS (18) will flash. When the flashing stops, the unit
is ready for use.

2. The ASSIGN (16, 21) buttons allow you to select which channel will be
displayed on each side of the BPM-1. Press the ASSIGN (16) button to
select channel 1, 2, 3 or 4 to be displayed on the left BPM DISPLAY
(17). The ASSIGN LED (15) will indicate the channel you selected.
Press the ASSIGN (21) button to select channel 1, 2, 3 or 4 to be
displayed on the right BPM DISPLAY (19). The ASSIGN LED (20) will
indicate the channel you selected.

3. BPM DISPLAY: There are BPM DISPLAYS (17, 19) for each side of the
BPM-1. They update approximately every 2.5 seconds and digitally
display the Beats Per Minute allowing you to match the beats visually.
BPM DISPLAY (17) reflects the Beats Per Minute of the channel
assigned to the left side of the unit, and BPM DISPLAY (19) reflects
the Beats Per Minute of the channel assigned to the right side of the
unit.

NONO

TETE

NO

TE: A [- -] reading will appear on the BPM DISPLAY if the

NONO

TETE
track has unclear beats. The [- -] reading will also appear if
there is no signal present.

4. The BEAT OFFSET INDICATORS (18) light when the tracks of the two

channels assigned to the crossfader are within 11 BPMs of each other
and display how aligned the beats of the two channels are. When the
RED LEDs light, the beats are not aligned. When the YELLOW LEDs
light, the beats are almost aligned. When the GREEN LED lights, the
beats are aligned perfectly.

NONO

TETE

NO

TE: If the difference between the two channel’s beats

NONO

TETE
exceed 11 BPM, the BEAT OFFSET INDICATORS will not
light.

SUGGESTION: You can use the BPM DISPLAYS to determine which
tracks have similar or the same Beats Per Minute. When mixing two tracks
with similar Beats Per Minute, you can use one source’s pitch control to
align the Beats Per Minute with the other source’s BPM. The BPM
DISPLAYS and the BEAT OFFSET INDICATORS update every 2.5
seconds and will reflect the change in BPM and indicate when the beats
are aligned.

NONO

TETE

NO

TE: Beat mixing is a skill that requires practice. Not

NONO

TETE
every track has a strong beat, and beat mixing works best
with tracks that have clear and strong beats.

Specifications

INPUTS:

Phono......................................................................................3 mV 3 MOhm

Line.....................................................................................150 mV 3 MOhm

OUTPUTS:

Input/Output Resistance..................................................................<0.1 Ohm

GENERAL:

BPM Range.............................................................................60 - 180 BPM

Power Adapter...........................................................115V/15V AC 500 mA

Dimensions......................................19”w x 1.75”h x 3”d (483 x 44 x 78 mm)

Weight.....................................................................................3 lbs (1.5 kg)

230V/15V AC 500 mA

Parts Lists

Cabinet Parts and Packing

Item #

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15

Item #

1
2

CASE
CHASSIS
KNOB PUSH
HOLDER LED (3ø 6.5mm)
PLATE DISPLAY (SMALL)
CLIP WIRE
SERIAL NO. LABEL
GIFT BOX
OWNER’S MANUAL
BAND-HEAD TAPPING SCREW (TWIN)
BAND-HEAD TAPPING SCREW/TW-E
BAND-HEAD TAPPING SCREW (TWIN)
BAND-HEAD TAPPING SCREW ( “NUT” )
BAND-HEAD TAPPING SCREW
NUT/WASHER

PRINTED CIRCUIT BOARD BPM1-1
PRINTED CIRCUIT BOARD BPM1-2

Description

Part #

031-032
021-461
002-571
003-732
003-372
049-190
196-061
255-131
157-962
110-166
121-003A
110-172A
111-044A
111-046A
131-057

Printed Circuit Boards

Description Part #

262-239
262-240

Page 3

Parts Lists - Meter PCB

Item #

1
2

Item #

1
2

3
4
5
6

ICs

Designators Description Part #

IC5
IC1

INTEGRATED CIRCUIT M66313FP
INTEGRATED CIRCUIT SC87C51CCN40

074-155
074-157

Electrical Parts

Designators Description Part #

A, B
D1-2, D6-7,
D20-27, D30
D3, D5
D4
SWA, SWB
XT1

LED NUMERIC DISPLAY
LIGHT EMITTING DIODE (RED) 3ø

LIGHT EMITTING DIODE (YELLOW) 3ø
LED (GREEN) 3ø
TACT SWITCH
CERAMIC RESONATOR 12 MHz

080-102
080-003

080-062
080-063
082-041
052-018

Parts Lists - Main PCB

Item #

1
2

Item #

1
2
3
4

ICs

Designators

IC2, IC3, IC4, IC8
IC7

INTEGRATED CIRCUIT UPC324
INTEGRATED CIRCUIT NJM7805FA

Description Part #

074-011
074-074

Electrical Parts

Designators Description Part #

D18
D8-10, D12-14
J1-4
SW1-4

RECTIFIER DIODE 1N4002 (1N4003,1N4004)
SILICON DIODE 1N4148
4P RCA JACK
SLIDE SWITCH 2P2C PH/LN

079-027
079-003
161-169
081-027

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