Page 1
Assembly Instructions
And
User Guide
Nixie Clock Type ‘Frank 3’
Software version: 5R
Hardware Revision:
12 Dec 07, 7 Jan 08
Nixie Clock ‘Frank 3’
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Table of Contents
1. INTRODUCTION ................................................................3
1.1 About the clock...............................................................3
1.2 Clock features.................................................................3
1.3 Safety ...........................................................................4
2. TOOLS AND EQUIPMENT REQUIRED
2.1 Tools required to assemble the PCB ...................................5
2.2 Materials you will need ....................................................6
2.3 Other items you will need ................................................6
...............................5
3. LIST OF COMPONENTS .......................................................6
3.1 Table of components .......................................................6
3.2 Parts list
3.3 How to identify the correct components .............................8
.................................................................7
4. ASSEMBLY OF THE PCB ......................................................9
4.1 Diodes D1-D4 .................................................................9
4.2 Diode D5 .......................................................................9
4.3 IC2 and C3.....................................................................9
4.4 IC1 and Q1 .................................................................. 10
4.5 C1, C2 and C5 .............................................................. 10
4.6 R1, R2, R3, R5, R6 ........................................................ 10
4.7 Variable resistor VR1 ..................................................... 11
4.8 MOSFET Q2 .................................................................. 11
4.9 Inductor L1 .................................................................. 12
4.10 Testing the 170V and 5V power supplies ........................ 12
4.10.1 Making up the Power Input Cable ............................... 12
4.10.2 Testing the power supplies ........................................ 14
4.11 Socket for IC3, IC4...................................................... 14
4.12 R28, C6, D6................................................................ 14
4.13 Q3-Q8, Q9-Q14, R7-R24 .............................................. 15
4.14 1mm Nixie Tube Sockets .............................................. 15
4.15 R25 ........................................................................... 15
4.16 Nixie Tubes IN-17 ....................................................... 15
4.17 SW1, SW2.................................................................. 16
4.18 Wire Link.................................................................... 16
5. FINAL TESTING OF PCB.................................................... 17
6. HOW TO OPERATE THE CLOCK ......................................... 18
7. CIRCUIT DIAGRAM .......................................................... 20
8. DIMENSIONED DRAWING ................................................ 21
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1. INTRODUCTION
1.1 About the clock
Nixie clock type ‘Frank 3’ is a compact design with all components
and tubes mounted on a single PCB. The efficient use of board
space is achieved by using a multiplex design to drive the display
tubes. Only a single high-voltage binary-to-decimal decoder IC
(74141) is required, and each tube is switched on in sequence very
quickly to give the illusion that all the tubes are actually lit.
The larger tubes for hours and minutes are type IN-12 with a digit
height of 18mm. The smaller tubes for the seconds are type IN-17
with a digit height of 9mm. These tubes are Russian in origin and
were produced during the 1980’s, when the technology was at it’s
most advanced. It is expected that the tubes will last for very many
years and should not need replacing.
The optional wooden case and hardware pack (rear cover, screws),
supplied rough-machined, can be finished to give a very attractive
clock for everyday living spaces. The quality of the final finish will
reflect the time and care that is taken to finish the wood with
successively finer grades of sandpaper. Alternatively, you may wish
to design your own enclosure for the clock
1.2 Clock Features
Nixie clock type ‘Frank 3’ has the following features:
- Hours, Minutes and Seconds display
- Uses the mains AC as the timebase
- Selectable at power-up to work with 50Hz (Europe) or 60Hz
(Americas)
- Simple time setting using two buttons
- 12 or 24 hour modes
- Maintains time during setup mode, eg. When changing between
Standard time and Daylight Savings Time
- Seconds can be reset to zero to make small adjustments /
precisely set time
- Three display modes: Blanked / Standard change of digits /
Fading digits
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1.3 SAFETY
DANGER: The clock pcb includes a switched-mode voltage booster
circuit. This generates nominally 180 Volts DC, but is capable of
generating up to 300 Volts before adjustment. Assembly may only
be undertaken by individuals who are suitably qualified and
experienced in electronics assembly, and are familiar with safe
procedures for working with high voltages. If in doubt, refer to a
suitably qualified engineer before proceeding.
The voltages generated by this circuit can give a potentially
LETHAL ELECTRIC SHOCK.
DISCLAIMER: This product is supplied as a kit of parts, intended
only for suitably qualified electronic engineers, who are suitably
qualified and experienced in electronics assembly, and are familiar
with safe procedures for working with high voltages. The supplier,
his agents or associates accept no liability for any damage, injury
or death arising from the use of this kit of parts.
This is not a finished product, and the person assembling the kit is
responsible for ensuring that the finished product complies with any
applicable local regulations governing electrical equipment, eg. UL,
CE, VDE.
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2. TOOLS AND EQUIPMENT REQUIRED
2.1 Tools required to assemble the PCB
The following tools will be required to assemble the PCB:
- Soldering iron with a small tip (1-2 mm)
- Wire cutters (TIP: A small pair of nail clippers works very well
for this function)
- Wire strippers (TIP: A small pair of scissors is quite suitable)
- Multimeter
- Small flat screwdriver for adjusting the high voltage supply
2.2 Materials you will need
Solder – lead / tin solder is preferred. Lead – free solder, as now
required to be used in commercial products in Europe, has a much
higher melting point and can be very hard to work with.
Desoldering wick (braid) can be useful if you accidentally create
solder bridges between adjacent solder joints.
2.3 Other items you will need
The clock kit does not include a power adapter. This is because the
kit is sold to many countries around the world, each with very
different household mains outlet socket types. It is more efficient
for the user to buy a suitable adapter locally. This saves shipping a
heavy adapter with the kit, and also the extra costs of managing
stocks of many varied power adapters.
The type of power adapter can be obtained at very low cost. The
following type of adapter should be obtained and used with the kit:
Mains AC to AC adapter (This is important, as the AC signal is
needed for the timebase)
Output 9-12V AC
Minimum power output capability of 250 mA
Output plug: 2.1mm pin
A suitable adapter is shown in figure 1 below:
Figure 1
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3. LIST OF COMPONENTS
3.1 Table of components (In sequence)
Circuit Designation Part Description
Resistors
R1 33K, ¼ Watt
R2 10K, ¼ Watt
R3 1K, ¼ Watt
R4 Not Installed
R5 470R, ¼ Watt
R6 220K, ¼ Watt
R7-R12 390K, ¼ Watt
R13-R22 5.6K, ¼ Watt
R23, R24 10K, ¼ Watt
R25 390K, ¼ Watt
R26 Not Installed
R27 Not Installed
R28 33K, ¼ Watt
Capacitors
C1 470uF, 16-25V, Electrolytic
C2 100uF, 16-25V, Electrolytic
C3 2.2nF ceramic or polyester
C4 Not Installed
C5 1uF, 250V, Electrolytic
C6 22nF, ceramic or polyester
Transistors
Q1 MPSA42 NPN
Q2 STP7NK30Z N-Channel MOSFET
Q3-Q8 MPSA92 PNP
Q9-Q14 MPSA42 NPN
Diodes
D1-D4 1N4001
D5 1N4936 fast recovery diode
D6 5.6V Zener Diode
D7 Not Installed
Integrated Circuits
IC1 78L05 5V voltage regulator
IC2 NE555 Timer IC
IC3 PIC16F627A 8 bit Microcontroller
IC4 74141 / K155N Nixie driver
Miscellaneous
L1 100uH – 220uH Inductor
NE1, NE2 4mm wire ended neon lamp
NX1-NX4 IN-12 Nixie tube
NX5, NX6 IN-17 Nixie tube
SW1, SW2 Miniature push button
VR1 1K Potentiometer
PCB ‘Frank 3’ PCB
IC Socket 18 Way IC Socket for IC3
CONN 2.1mm Power socket
Cable ~60mm two way cable
SKT1-44 1mm Harwin solder-in socket
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3.2 Parts list / Packing sheet
Part Description Quantity
Resistors
33K, ¼ Watt 2
10K, ¼ Watt 3
1K, ¼ Watt 1
470R, ¼ Watt 1
220K, ¼ Watt 1
390K, ¼ Watt 7
5.6K, ¼ Watt 10
Capacitors
470uF, 16-25V, Electrolytic 1
100uF, 16-25V, Electrolytic 1
2.2nF ceramic or polyester 1
1uF, 250V, Electrolytic 1
22nF, ceramic or polyester 1
Transistors
STP7NK30Z N-Channel MOSFET 1
MPSA92 PNP 6
MPSA42 NPN 7
Diodes
1N4001 4
1N4936 fast recovery diode 1
5.6V Zener Diode 1
Integrated Circuits
78L05 5V voltage regulator 1
NE555 Timer IC 1
PIC16F627A 8 bit Microcontroller 1
74141 / K155N Nixie driver 1
Miscellaneous
100uH – 220uH Inductor 1
4mm wire ended neon lamp 2
IN-12 Nixie tube 4
IN-17 Nixie tube 2
Miniature push button 2
1K Potentiometer 1
‘Frank 3’ PCB 1
IC Socket, 18 way DIL 1
2.1mm Power Connector 1
Cable – 60mm piece 1
1mm Harwin solder-in socket 44
It is recommended that the kit is checked against the list above, to
ensure all parts are present before commencing assembly.
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3.3 How to identify the correct components
Resistors:
The resistors are easy to identify by the coloured bands
across the cylindrical body. Using a multimeter it should will
be possible very quickly to identify the different values.
Capacitors:
Take care when identifying the 2 small ceramic or polyester
capacitors. Depending on part availability, 2 or more different
types may be supplied. The 22nF capacitor (C6) may be
marked 22nF, 22n, or 223. The 2.2nF capacitor (C3) may be
marked 2.2nF, 2.2n, or 222.
Transistors:
The MOSFET Q2 can easily be identified as it has a large
metal heatsink. Note: Due to part availability, this part may
be substituted for a different but equivalent part number so
the part marking may not necessarily be ‘STP7NK30Z’. One
alternative part number is ‘IRF730’.
Diodes:
The four 1N4001 diodes D1-D4 are black and are marked
1N4001. The other black diode is D5, and again due to part
availability it may be substituted for an equivalent.
D6 is the small, glass bodied diode
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4. ASSEMBLY OF THE PCB
4.1 Diodes D1-D4
Start by bending the leads of the four diodes to approximately
match the spacing of the holes on the PCB. Insert the four diodes
taking care to match up the white bands on the components with
the component marking on the PCB. See Figure 2 below.
Figure 2
Solder in the diodes, then using the wire clippers trim off the leads.
4.2 Diode D5
D5 is the remaining black diode. Again noting the position of the
white band, place in position, solder in and trim the leads.
4.3 IC2 and C3
IC2 must be oriented correctly. The notch or dot at one end
corresponds to pin 1. This goes into the SQUARE pad. Also place
and solder in C3.
Figure 3 shows D5, IC2 and C3 correctly placed.
Figure 3: IC2, C3 and D5
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4.4 IC1 and Q1
IC1 and Q1 look very similar, so be careful to identify them
correctly by the white marking on each component. The leads
should not need to be formed, just separated a little. Align the flat
of the body of these components with the marked flat on the PCB.
Push each component into it’s holes until the body is just 2 mm
from the pcb. Solder in and trim the leads.
4.5 C1, C2 and C5
Now it is time to solder in the three electrolytic capacitors. These
components must be placed the correct way round or else the
circuit will fail. Each capacitor has a positive lead, which has the
longer lead, and a negative lead, marked by a white or grey stripe
on the body. In Figure 5, the longer lead (+ve) and white stripe (VE) can be clearly seen.
Figure 5: C5, C2, C1
Place each component with the longer lead on the hole marked ‘+’.
Solder in and trim the leads.
4.6 R1, R2, R3, R5, R6
Note that R4 is marked on the board, but is not used for this clock.
These resistors, indeed all the resistors on the board need to be
mounted upright to save space. The leads need to be formed as
shown in figure 6. Bent the leads of each resistor as shown and
solder in to the correct postion, making sure the component body
is as close to the board as possible.
Nixie Clock ‘Frank 3’
Figure 6: Resistor
leads formed for
mounting upright.
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4.7 Variable Resistor VR1
VR1 is used to tune the switched mode power supply to give the
optimum voltage to drive the Nixie tubes (170-180V). If is has a
side facing adjustment screw, ensure it is placed with the
adjustment screw facing outwards!
4.8 MOSFET Q2
The board is very densely populated in this area. The leads of the
MOSFET need to be bent very carefully to allow the MOSFET to ‘lie
flat’, as otherwise it would stand too high and foul any case that
the clock will be put into. Follow the bending profile in figure 8,
then place and solder Q2 into position as shown in figure 9.
Figure 7: Mount the
Variable resistor VR1 with
the adjustment screw
pointing OUTWARDS.
Figure 8:
Bending the leads of
MOSFET Q2.
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Figure 9: Q2
mounted in position,
avoiding R5 and IC2
If necessary, bend the position of Q2 after soldering, to make sure
it is not touching R5 or IC2.
4.9 Inductor L1
Place L1 in position, and ensure it is as close to the board as
possible. The leads of the component may not match exactly the
spacing on the board – this is perfectly normal. You can slightly
form the leads so it is a nice firm and snug fit to the board. Solder
and trim the leads as short as possible.
4.10 Testing the switched mode (170V) and regulated (5V)
power supplies.
If you have reached this point and followed the correct order, then
all the components for the 170V and 5V power supplies should now
be on the board, and it is recommended that at this point the
power supplies are tested before proceeding. To do so, you will
need to make up the power input cable and socket, and of course
have the 9-12V AC power adapter to hand. Also at this stage you
will need a small flat blade screwdriver and a multimeter.
DANGER: At this point, observe the safety warnings in section 1.3.
When powered up, the board will generate up to 300V DC, and live
parts are exposed. Observe high-voltage precautions.
4.10.1 Making up the power input cable
Take the length (approx 60mm) of two way cable provided and
strip the insulation for about 5 mm from all four ends. Note, the
cable may be a different colour to that shown, and the insulation
may be the same colour for both sides. As this cable carries AC,
the conductors are not polarised. Referring to Figures 10-13, tin
the ends of the cables, and solder to the 2.1mm connector as
shown. Only 2 tags are used on the connector.
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the copper conductors.
PCB
Figure 10: Connector and
60mm piece of two way
cable.
Figure 11: Strip the insulation
from the cable ends, and tin
Figure 12: Close-up showing
which two tags need to be
connected. Note: If you
purchased the part-machined
case, you will need to flatten
the three solder terminals to
stop them touching the circuit
board when the cover is fixed.
Figure 13: Connect the power
input leads to the pads on the
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Connect the other ends of the cable to the circuit board as
14: Socket for IC3, and
shown in Figure 13. It is not necessary to feed the wire through
the holes, you can just lay the tinned ends over the pads and
solder in place.
4.10.2 Testing the power supplies
First adjust the variable resistor VR1 to approximately the
middle position. Then switch on the power supply.
First, check that the 5V supply is in order. Use the GND, 5V and
170V test points to test first the 5V supply, then the 170V
supply. Adjust the position of VR1 until the voltage is 170V.
When all is in order, disconnect the power supply. Take care, as
the output capacitor can still hold charge at 170V after the
supply is disconnected. Before proceeding with the rest of the
PCB assembly, it is a good idea to de-solder the power input
cable, as it can get in the way when soldering the remaining
components.
4.11 Socket for IC3, IC4.
Insert the 18 Way IC socket into the PCB, ensuring that the notch
at one end is aligned with the corresponding mark on the PCB.
Insert IC4 directly into the PCB. Solder both components in place,
but do NOT insert IC3 at this stage. This will be inserted at the very
end of the assembly. Refer to figure 14.
4.12 R28, C6, D6.
Nixie Clock ‘Frank 3’
Figure
IC4
R28 should be placed vertically. The lead pitch of C6 may not
match exactly the pitch of the holes on the PCB. If so, bend the
leads sufficiently to insert the component. D6 needs to be placed
the correct way round, so ensure the black band on the component
body aligns with the band on the PCB marking.
Note: R27 is not used. Also, ignore the markings referring to
‘DCF77’ PCB. This feature will be implemented in future versions.
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4.13 Q3-Q8, Q9-Q14, R7-R24
This is perhaps the most time consuming stage of the assembly.
There are six Anode Driver Clusters. The function of each is to take
the Logic output from the 5V microcontroller, and switch on the
170V Anode drive to the respective nixie tube.
Pay particular attention to installing the correct Transistor type
(MPSA42 or MPSA92) in the correct location.
4.14 1mm Nixie tube sockets.
There are 44 individual 1mm sockets to solder in. For each Min /
Hour Nixie tube there are 11 sockets, however there are 12 holes.
On the PCB, the four locations are marked where NO socket should
be installed. Proceed as follows:
Solder in the sockets for a single tube at a time (11 sockets). Place
all the sockets, then place a flat object over the top of the sockets
to keep them from falling and invert the PCB to solder the sockets
in place. A third hand, from a helper, is most useful at this stage!
Do not insert the IN-12 Nixie tubes at this stage.
4.15 R25
Install R25, the current limiting resistor for the 2 neon lamp
Hour:Minute separators.
4.16 Nixie tubes IN-17
To facilitate easy insertion of the flying leads into the small holes, it
helps enormously to trim the flying leads at an angle with a pair of
scissors as shown in figure 15.
Figure 15: IN-17
flying leads trimmed
to aid insertion into
the PCB
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Feed all the wires in progressively. It is not as hard as it seems at
first. Ensure the tubes are the correct way up. The part marking
IN-17 should be to the RIGHT, but also check above to see ig you
can tell that the 5 and 3, which are visible, are the correct way up.
After soldering in, trim flying leads.
4.17 SW1, SW2.
Push buttons SW1 and SW2 are mounted on the REVERSE side of
the PCB, so that the clock is adjusted from the back. You can
choose to mount them on the front face if you wish, depending on
your own particular clock case design.
4.18 Wire Link (Applicable to PCB dated 12 Dec 07 only)
If your PCB is dated 12 Dec 07, there is a small error on the board
that needs to be corrected with a small wire link.
First (Figure 16), on the reverse side of the board, locate the small
plated through hole and pin 1 of IC2 as shown.
figure 16
Then, insert and solder a small wire into the plated through hole.
Attach the other end to pin 1 of IC2 as shown below in figure 17
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Figure 17:
modification
to correct
board error
Ensure the wire does not contact any other parts of the circuit.
5. FINAL TESTING OF PCB
All components except the 2 neon lamps should now have been
installed. These can be installed later, when the unit is in it’s final case
to make sure they are set at the correct height.
Make a final check that all components are well soldered in, and that
there are no solder bridges – unintentional solder links between
adjacent pins.
Insert IC3, matching up the notch on the resin body with the notch on
the socket and the PCB markings.
Insert the four IN-12 Nixie tubes into their sockets. It is quite easy to
tell which way up they should be by looking into the glass at the
numerals. Do not insert too hard, or you may break the glass seal at
their base.
Re-solder the power input cable, if you removed it for ease of
assembly.
The clock is now ready for use!! Don’t forget to install the Neon
Lamps, when you have finished your enclosure.
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6. HOW TO OPERATE THE CLOCK
The two buttons have the following functions:
SW1: Set / Blank
SW2: Up / Reset Seconds
Setting 50Hz or 60Hz Mode
With the clock powered off, hold BOTH buttons down. Power up the clock
and either 50 or 60 will display, indicating the current mode stored in
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flash memory. Use either button to toggle between 50 and 60 to select
the correct frequency for your local electricity supply. Then power off the
clock, and the value is stored in flash memory.
Setting the time:
Press and hold ‘Set / Blank’ button for 3 seconds until the seconds
flashes ‘24’.
Toggle between 12 and 24 hour modes by pressing the ‘Up / Reset Secs’
button.
Briefly Press ‘Set / Blank’ again and the minutes will flash. Press the ‘Up /
Reset Secs’ button to set the minutes.
Briefly Press ‘Set / Blank’ again and the hours will flash. Press the ‘Up /
Reset Secs’ button to set the hours.
Briefly Press ‘Set / Blank’ again to revert to normal clock operation.
Resetting seconds:
From normal clock operation, press and hold ‘Up / Reset Secs’ button for
2 seconds. Seconds will be set to zero, and held until the button is
released.
Setting the display mode:
Briefly Press ‘Set / Blank’ button to toggle between the three display
modes:
1. Blanked display, tubes are switched off eg for tube saving or for
night time
2. Standard change of digits
3. Fading digits
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7. CIRCUIT DIAGRAM
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8. DIMENSIONED DRAWING
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