GEKCO CLK056 Supplement

GEKCO
DIGITAL CLOCK
MODEL CLK056
ASSEMBLY & OPERATION MANUAL
GEKCO Inc.
1565 SW Cypress Ln
McMinnville, OR 97128
[phone] P/N 595-325 REV 181030
Copyright 2018
GEKCO Inc.
All Rights Reserved
Printed in the United States of America
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GEKCO DIGITAL CLOCK P/N CLK056 ASSEMBLY & OPERATION MANUAL
GEKCO INC. Rev 1.0 1
TABLE OF CONTENTS
1. INTRODUCTION................................................................................................................................................ 3
2. OPERATIONAL SUMMARY.......................................................................................................................... 3
3. PARTS AND UNPACKING.............................................................................................................................. 4
3.1. TOP LEVELPARTS LIST ...................................................................................................................................... 4
3.2. DISPLAY BOARD PARTS LIST.............................................................................................................................. 5
3.3. MAIN BOARD PARTS LIST................................................................................................................................... 6
3.4. FINALASSEMBLY HARDWARE PARTS LIST....................................................................................................... 7
3.5. ENCLOSURE PARTS LIST..................................................................................................................................... 8
4. ASSEMBLY NOTES........................................................................................................................................... 9
4.1. TOOLS............................................................................................................................................................... 9
4.2. ASSEMBLY ...................................................................................................................................................... 9
4.3. SOLDERING..................................................................................................................................................... 9
5. STEP-BY-STEP ASSEMBLY .........................................................................................................................10
5.1. DISPLAY CIRCUIT BOARD.................................................................................................................................10
5.2. MAIN CIRCUIT BOARD......................................................................................................................................14
6. INITIAL TESTS.................................................................................................................................................16
7. FINAL TESTS....................................................................................................................................................17
8. IN CASE OF DIFFICULTY............................................................................................................................17
9. FINAL PCA ASSEMBLY................................................................................................................................17
10. FINAL ASSEMBLY......................................................................................................................................17
11. THEORY OF OPERATION.......................................................................................................................20
11.1. BLOCK DIAGRAM..............................................................................................................................................20
11.1. MAIN BOARD CIRCUIT DESCRIPTION...............................................................................................................20
11.2. DISPLAY BOARD CIRCUITDESCRIPTION.......................................................................................................... 21
12. FIRMWARE.................................................................................................................................................. 22
12.1. FLOW CHART ....................................................................................................................................................22
12.2. FIRMWARE DESIGN DESCRIPTION....................................................................................................................23
13. PCA PICTORIAL DIAGRAMS.................................................................................................................23
13.1. MAIN BOARD....................................................................................................................................................23
13.2. DISPLAY BOARD ...............................................................................................................................................24
14. SCHEMATIC MAIN BOARD.................................................................................................................... 26
15. SCHEMATIC DISPLAY BOARD.............................................................................................................27
16. DOCUMENT REVISION HISTORY........................................................................................................28

GEKCO DIGITAL CLOCK P/N CLK056 ASSEMBLY & OPERATION MANUAL
2 REV 1.0 GEKCO INC.
LIST OF FIGURES
FIGURE 1: DISPLAY BOARD TOP SIDE COMPLETED ASSEMBLY.......................................................................... 10
FIGURE 2: DISPLAY BOARD BOTTOM SIDE COMPLETED ASSEMBLY..................................................................10
FIGURE 3DISPLAY BOARD BOTTOM SIDE............................................................................................................ 11
FIGURE 4: DISPLAY BOARD TOP SIDE ASSEMBLY PICTORIAL.............................................................................12
FIGURE 5: MAIN BOARD COMPLETED ASSEMBLY...............................................................................................14
FIGURE 6MAIN BOARD TOP VIEW 1.................................................................................................................... 14
FIGURE 7: MAIN BOARD TOP VIEW2...................................................................................................................14
FIGURE 8: MAIN BOARD TOP VIEW3...................................................................................................................14
FIGURE 9: MAIN BOARD TOP VIEW4...................................................................................................................15
FIGURE 10: MAIN BOARD WITH STANDOFFS......................................................................................................... 15
FIGURE 11: MAIN AND DISPLAY BOARD INTERFACE CONNECTOR MOUNTING...................................................15
FIGURE 12 RTCMODULE ASSEMBLY..................................................................................................................17
FIGURE 13 ENCLOSURE BACK.............................................................................................................................. 18
FIGURE 14 ENCLOSURE BACK WITH TOP .............................................................................................................18
FIGURE 15 DISPLAY BOARD TOP SIDE ................................................................................................................. 24
FIGURE 16 DISPLAY BOARD BOTTOM SIDE..........................................................................................................25

CLK056
GEKCO INC. Rev 1.0 3
1. Introduction
The Digital Clock Model CLK056 was designed to fill the need for an accurate digital clock with the
capabilities of two time zone displays in a compact format.
This clock has 6 digits for hours, minutes and seconds and the hours display can alternate between
two time zones, i.e. Coordinated UniversalTime (UTC) and local time.
The CLK056 is offered in kit form or fully assembled and tested. The kit is veryeasy to assemble with
no surface mount parts.
This step bystep manual will guide you through the process to complete the assembly and testing of
the model CLK056 Digital Clock. The manual was designed so a total beginner in electronics can be
successful but the more experienced builder can skip anyunnecessary information. Also this design is
fully open source for both the hardware and firmware. There are full schematics and pictorial diagrams
of the hardware, also there are links and flowcharts of the firmware microcontroller code.
2. Operational Summary
The Model CLK056 has 6 digits of seven segment displays to displayHOURS, MINUTES and
SECONDS. The HOURS displaycan alternate between two time zones, which can be UTC and local
time. This function can be turned off bya menu selection if desired.
The six digit displayprovides Hours, Minutes andSeconds
Dual time zone display, alternates between two time zones every2 seconds, i.e. UTC and local
The display LEDs are high contrast red, 0.56 inch character height
Adjustable display brightness
Local hours can be set for 12 or 24 hour mode
Very accurate Real Time Clock (RTC) with battery backup
Powered bya U.L. listed 5 VDC wall adapter
Size: 4.16x 2.35 x 1.46 inches (Width x Height x Depth)
Weight: 0.30 pounds

GEKCO DIGITAL CLOCK P/N CLK056 ASSEMBLY & OPERATION MANUAL
4 REV 1.0 GEKCO INC.
3. Parts and Unpacking
The kit is packaged in the order that the assembly is recommended. Each assembly block has it’s
associated parts bag. Only open a parts bag when called for during assembly to avoid misplacing parts.
3.1. Top Level Parts List
Remove the parts from the main bag and separate each individual parts bags.
ITEM
QTY
PART NO.
DESCRIPTION
1
1
DBR656-KIT
Clock DisplayBoard PCA parts bag
2
1
CLK056M-KIT
Clock Main Board PCA parts bag
3
1
2217625
Real Time Clock (RTC) Module DS3231
4
1
CLK056HDW-KIT
Final Assembly Hardware
5
1
CLK0X6ENC-KIT
Enclosure Acrylic 6 Piece
6
1
54-660
AC to DC Power SupplyWall Adapter Single
Output 5 Volt 1 Amp 5 Watt 2.1mm Conn

DIGITAL CLOCK MODEL CLK056
GEKCO INC. Rev 1.0 5
3.2. Display Board Parts List
Clock 056 Display Board Printed Circuit Assembly (PCA) parts kit, P/N DBR656-KIT
ITEM
QTY
REFDES
PART NO.
DESCRIPTION
1
3
DS1,DS2,DS3
412-499
LED DisplayModule 7-Segment 2-Digit 0.56"
2
1
X1
434-3110
Socket IC Dip24-300
3
1
U1
442-3090
IC LED DisplayDriver MAX7219CNG
4
1
J1
131-1X10
Connector Header Single Row Male 10 pins
5
4
LED3,LED4,
LED5,LED6
412-125
LED Red PCB Mount T1 3/4
6
1
C2
26-102
Cap elect alum radial lead 10uF/16v
7
1
C1
20-104
Cap mono Cer 50v radial lead
8
1
R1
6-1002-12
Res metal film 1/4w 1% 10k
9
1
81-180911D
PCB DisplayBoard
1
2 3 8
6
5
7
4
3

GEKCO DIGITAL CLOCK P/N CLK056 ASSEMBLY & OPERATION MANUAL
6 REV 1.0 GEKCO INC.
3.3. Main Board Parts List
Clock 056 Main Board PCA parts kit, CLK056M-KIT
ITEM
QTY
REFDES
PART NO.
DESCRIPTION
VALUE
1
3
C4,C5,C6
20-104
Cap mono Cer 50v radial lead
0.1UF
2
2
C1,C2
21-220
Cap mono Cer COG radial
lead
22pF 100v
3
1
C3
26-102
Cap elect alum radial lead
10uF/16v
4
1
Y1
404-160
Crystal HC49
16.00 MHz
5
1
D1
55-62
Diode schottkyrectifier
1N5817-T
6
3
SW1,SW2,S
W3
64-1839
Switch Momentary SPST
7
1
SW4
64-1827
Switch Momentary5mm H
8
1
J4
131-1X10S
Conn Header Female Single
Row 10 pins
9
1
J2
131-1X06RA
Conn Header Right Angle
Male 1 row of 6
pins
10
1
J3
131-1X05RA
Connector Header Right Angle
Male 1 row of 5
pins
11
1
J1
134-002
Connector Power 2.1mm PCB
Mount
12
1
RN1
95-103
Res network 6 sip
10K 5 Res SIP
Package
13
1
X1
434-311
Socket IC
Dip28-300
14
1
U1
444-104-01
IC Microcontroller
Programmed
Part CLK056
V1.01
15
1
LS1
220-1420
Audio Piezo Transducer 30V
16
1
81-180912C
Printed Circuit Board
Main Board
1
2
3
4
5
6
7
8
9 10
11
12
13
14
15
16

DIGITAL CLOCK MODEL CLK056
GEKCO INC. Rev 1.0 7
3.4. Final Assembly Hardware Parts List
Clock 056 Final AssemblyHardware parts kit, P/N CLK056HDW-KIT
ITEM
QTY
PART NO.
DESCRIPTION
1
2
255-25511
Hardware Standoff Nylon M3 x 12 mm
2
4
255-29341
Hardware Screw Nylon M3 x 0.50 mm Thread,
6mm White (used for temporary assembly only)
3
2
255-29346
Hardware Screw Nylon M3 x 0.50 mm Thread,
16mm White
4
2
255-29347
Hardware Screw Nylon M3 x 0.50 mm Thread,
20mm Black
5
2
255-876
Hardware Spacer Round 0.25" Hole Size #4
21
4
3
5

GEKCO DIGITAL CLOCK P/N CLK056 ASSEMBLY & OPERATION MANUAL
8 REV 1.0 GEKCO INC.
3.5. Enclosure Parts List
Clock 056 Enclosure kit, P/N CLK0X6ENC-KIT
ITEM
QTY
PART NO.
DESCRIPTION
1
1
86-18111901
Front Panel Acrylic 3mm Transparent Red
2
1
86-18111902
Back Panel Acrylic 3mm Clear
3
1
86-18111903
Top Panel Acrylic 3mm Clear
4
1
86-18111904
Bottom Panel Acrylic 3mm Clear
5
1
86-18111905
Left Side Panel Acrylic 3mm Clear
6
1
86-18111906
Right Side Panel Acrylic 3mm Clear
7
1
86-18111907
Front Window Label
1
56
2
7
3
4