Pvelectronics IN-8 Configuration guide

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
- 1 -
ssembly Instructions
nd
User Guide
Nixie Clock Type
‘IN-8 & NL840 Nixie'

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
- 2 -
REVISION HISTORY
Issue
Number
Date Reason for Issue
4 15 December 2016 New diode for D2
3 30 August 2014 Typos
2 25 June 2014 Added N 840 tubes
1 12 May 2014 New document

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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1. INTRODUCTION
1.1 bout the clock
Nixie clock type ‘IN-8 & N 840 Nixie' 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 3 X 2 multiplex design to drive the
display tubes. Two slightly different PCBs cater for 2 tube types:
IN-8 tubes are a plug-in type, with a digit height of 18mm. 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.
N 840 and compatible tubes have a digit height of 15.5mm. These tubes
typically have a fine anode mesh, allowing a very crisp and clear view of
the digits.
Other tubes compatible with the N 840 PCB are as follows:
N 841, N 842, N 844, N 845, N 846, N 821, N 812, N 807, Raytheon
CK8754.
Software
The main controller is the 8-bit PIC16F1936 running at 16Mhz. The code
is programmed entirely in the ‘C’ programming language.
Drive Mode
The tube cathodes are driven by a HV5812 High Voltage Driver IC by
Supertex. With 20 outputs, it is able to drive the six Nixie Tubes in a very
comfortable and low noise 3X2 multiplex.
GPS Time Synchronisation
A radical new clock design deserves a new and exciting GPS receiver
module for those that demand the best timekeeping. And, with a
groundbreaking price for a GPS receiver, a fully featured Nixie Clock with
GPS synchronisation is now within the price range of most buyers.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
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1.2 Clock features
The Nixie Clock has the following features:
- Hours, Minutes and Seconds display
- 12 or 24 hour modes
- Uses a Quartz Crystal Oscillator as the timebase
- Programmable leading zero blanking
- Date display in either DD.MM.YY or MM.DD.YY or YY.MM.DD format
- Programmable date display each minute
- Scrolling display of date or standard display
- Alarm, with programmable snooze period
- Optional DCF / MSF / GPS synchronisation with status indicator ED
- Dedicated DST button to switch between DST and standard time
- Supercapacitor backup. Keeps time during short power outages
- Simple time setting using two buttons
- Programmable leading zero blanking
- Five programmable neon colon settings (Flashing AM/PM indication,
illuminated AM/PM indication, both flashing, both on, both off)
- Seconds can be reset to zero to precisely the set time
- Programmable night mode - blanked or dimmed display to save tubes
or prevent sleep disturbance
- Rear Indicator EDs dim at night to prevent sleep disturbance
- Weekday aware ‘Master Blank’ function to turn off tubes and EDS on
weekends or during working hours
- Separate modes for colon neons during night mode
- Standard, crossfading, or crossfading with scrollback display modes
- ‘Slot Machine’ Cathode poisoning prevention routine
- Programmable ED tube lighting – select from 10 brightness levels for
each hour of the day.
- Not AC frequency dependent – works in all countries
- All user preferences stored to non-volatile memory

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
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1.3 S FETY
D NGER: The clock pcb includes a switched-mode voltage booster
circuit. This generates nominally 170 Volts DC. 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
LETH L ELECTRIC SHOCK.
DISC AIMER: 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. U , CE,
VDE.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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2. TOOLS ND 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 to trim the excess component leads after soldering.
(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 for voltage tests and for identifying the resistors.
2.2 Materials you will need.
Solder – lead / tin solder is highly recommended. USE EAD/ TIN
SO DER!.
ead 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. If you are using a DCF or MSF receiver avoid cheap
Chinese switching power supplies, as they can cause interference
problems.
The appropriate type of power adapter can be obtained at very low cost.
The following type of adapter should be obtained and used with the kit:
Output 12V DC regulated, minimum power output capability of 500 mA
Output plug: 2.1mm pin, centre po itive.
A suitable adapter is shown below:

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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3. LIST OF COMPONENTS
3.1 Table of Components
Circuit Designation Part Description
Resistors
R1 4.7 KΩ, ¼ Watt
R2 390 KΩ, ¼ Watt
R3 4.7 KΩ, ¼ Watt
R4 390 KΩ, ¼ Watt
R5 4.7 KΩ, ¼ Watt
R6 - R8 270 Ω, ¼ Watt
R9 – R11 4.7 KΩ, ¼ Watt
R12 – R14 390 KΩ, ¼ Watt
R15 – R17 10 KΩ, ¼ Watt
R18 - R25 4.7 KΩ, ¼ Watt
R26, R27 390 KΩ, ¼ Watt
R28 4.7 KΩ, ¼ Watt
R29 - R34 270 Ω, ¼ Watt
Capacitors
C1, C2 100nF Ceramic
C3 1uF, 250V, Electrolytic
C4 470uF, 16-25V, Electrolytic
C5 15pF Ceramic
C6 33pF Ceramic
C7 100nF Ceramic
C8 0.1F or 0.22F
C9, C10 100nF
Transistors
Q1 IRFD220 MOSFET
Q2 MPSA42
Q5 – Q7 MPSA42
Q8 – Q10 MPSA92
Q11 - Q13 MPSA42
Diodes
D1, D3 1N5819
D2 1N4001
D4 UF4004
D5 62V Zener Diode
D6 5mm Green ED
D7, D8 5mm Yellow ED
D9 - D14 3mm ED (various colours)
Integrated Circuits
IC1 7805 5V voltage regulator
IC2 PIC16F1936 8-bit microcontroller
IC3 HV5812
Miscellaneous
1 100uH Inductor
AM, PM 4mm Wire ended neon lamp
A ARM, SET, ADJ, DST Miniature push button
IC2 Socket 28 Way narrow IC socket for IC2
IC3 Socket P CC28 IC socket for IC3

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
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J1 2.1mm PCB power socket
GPS / RFT SMD 3.5mm jack socket
S1 Piezo sounder
FUSE 500mA fuse
Insulation Clear insulation for neons
X1 32.768KHz watch crystal

Nixie Tube Clock 'IN-8 & NL840 Nixie'
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3.2 Parts list / Packing Sheet (Component Bag)
Part Description Quantity
Resistors
270 Ω, ¼ Watt 9
4.7 KΩ, ¼ Watt 15
10 KΩ, ¼ Watt 3
390 KΩ, ¼ Watt 7
Capacitors
33pF, Ceramic 1
15pF, Ceramic 1
100nF, Ceramic 5
1uF, 250V, Electrolytic 1
470uF, 16-25V, Electrolytic 1
0.1F or 0.22F 1
Transistors
IRFD220 MOSFET 1
MPSA42 7
MPSA92 3
Diodes
1N5819 2
1N4001 1
UF4004 Fast recovery diode 1
5mm Green ED 1
5mm Yellow ED 2
3mm Coloured ED 6
62V Zener diode 1
Integrated Circuits
7805 5V voltage regulator 1
PIC16F1936 8-bit microcontroller 1
HV5812 1
Miscellaneous
100uH Inductor 1
4mm Wire ended neon lamp 2
Miniature push button 4
28 Way narrow IC Socket for IC2 1
P CC28 IC Socket for IC3 1
2.1mm PCB power socket 1
SMD 3.5mm Jack socket 1
Piezo sounder 1
500mA fuse 1
Clear insulation for neons 1
1mm Socket Receptacle 66
32.768KHz Watch crystal 1

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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It is recommended that the kit is checked against the list above, to
ensure all parts are present before commencing assembly. Don’t be
alarmed if there are some extra components, as some component
bags are shared between different kit types.
The resistors used in the kit are 1% tolerance metal film. They are
marked with 4 coloured bands to identify the value. However it is
sometimes unclear in which direction the bands should be read.
Therefore, we recommend that the resistors be identified with a
multimeter.
Please note the fuse will look like the picture below. It can easily be
confused for a capacitor. It is a self-resetting fuse.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
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www.pvelectronics.co.uk
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5. SSEMBLY OF THE PCB - P RT 1
DUE TO PRODUCT DEVE OPMENT AND IMPROVEMENTS, YOUR PCB
MAY NOT OOK EXACT Y IKE THE ONE PICTURED.
5.1 66X 1mm Sockets For Nixie Tubes
There are 2 different types of sockets that maybe supplied with the
kit. They are either gold or silver in appearance. Please proceed
below according to the socket type supplied with your kit:
Silver Sockets:
There are 66 individual sockets that need to be soldered in. The
best method is a follows. Place all sockets into the holes, noting
that for each tube there is one hole that has no socket as shown
below. When all sockets have been placed, place a flat and hard
object over the top of the sockets, and turn the PCB over so you
can solder from the underside. Be sure to insert the sockets FROM
the solder of the PCB – the side with less white component
markings. The photo below shows the solder side of the PCB after
all the sockets have been inserted and soldered in.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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Gold Sockets:
There are 66 individual sockets that need to be soldered in. The
best method is a follows.
IN-8: Slide 11 sockets onto the 11 pins of the tube.
N 84x: Slide 10 sockets onto the 10 outer pins on the tube. With
reference to the PCB check which of the inner pins is needed (the
corresponding hole on the PCB is plated), and slide a socket over
this pin too.
Insert the tube with sockets into the PCB noting the white marking
on the side from which the sockets should be inserted. This side is
marked ‘Insert sockets from THIS side’.
Ensuring the tube is fully straight and vertical, solder the sockets.
The tube can then be withdrawn.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
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5.1 Low Voltage Power components:
J1, FUSE
D1, D3 (1N5819)
D2 (1N4001)
IC1 (7805)
C1, C2 (100nF)
Start by installing D1-D3. Align the white band on the components
with the band marked on the PCB.
After placement, IC1 can be placed and bent over these diodes to
reduce the height of the assembled PCB. Continue to mount C1,
C2, J1 and FUSE.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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5.2 Testing Low Voltage Power Supply.
Identify the test GND, 5V and HV test points as shown below.
Plug in the power supply, and then test using a DC voltmeter:
Touch the black probe on the GND test point and the red probe on
the 5V test point. The voltage should measure between 5.6 and 5.9
Volts. If not, disconnect power and check your work. Do not
proceed with the assembly until the error is corrected. Once the
test is completed, disconnect the power.
5.3 High Voltage generator components.
Socket for IC2
R1, R3 (4.7 KΩ)
R2, R4 (390 KΩ)
C3 (1uF)
C4 (470uF)
Q1 (IRFD220)
L1 (100uH Inductor)
D4 (UF4004)
D5 (62V Zener diode)

Nixie Tube Clock 'IN-8 & NL840 Nixie'
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All the resistors on the board need to be mounted upright to save
space. The leads need to be formed as shown below. Bend 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.
Take care that the notched end of the IC socket is at the end
shown. Also the MOSFET needs to be placed with the two joined
pins at the position shown below.
The two capacitors C3 and C4 are polarised. The longer lead goes
in the hole marked '+'.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
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5.4 High Voltage Generator Test.
- Refer to the warnings on page 5
- Insert IC2 into its socket. Orient the notch on the IC with the
notch on the IC socket and the PCB marking.
- Power up the PCB, and using the GND and HV test points,
measure the high voltage generated using a voltmeter on DC
setting. It should be between 167V and 173V. If this is in order,
disconnect the power supply.
Finally, remove IC2 from its socket and replace on its static-
protective foam. It is best kept safe until needed for the tube tests
later in the assembly.
5.5 R5, R9 - R11, R18 - R23 (10 X 4.7 KΩ)
R12, R13, R14 (390 KΩ)
R15, R16, R17 (10 KΩ)
5.6 Q5, Q6, Q7 (MPS 42)
Q8, Q9, Q10 (MPS 92)
5.7 C5 (15pF)
C6 (33pF)
X1 (32.768KHz Crystal)

Nixie Tube Clock 'IN-8 & NL840 Nixie'
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5.8 Socket for IC3
Align the notch on one corner of the socket with the marking on
the PCB. Be careful not to force in the socket if all pins are not
aligned. Ensure all pins are fully pushed through the holes before
soldering in place.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
www.pvelectronics.co.uk
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6. FIRST TUBE TEST
It is now time to check the basic display functions and that all
tubes are working correctly.
6.1 FIRST TEST
Insert IC2 and IC3 into their sockets, with the notches aligned as
shown below:
Connect a 12V DC power supply (2.1mm central pin type, centre
positive) and power up.
The clock should start counting 0-9 repeatedly on all tubes. If this
does not happen, power off and check all tubes are connected
correctly.
Power off and disconnect the power supply.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
Issue 4 (15 December 2016)
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7. SSEMBLY - CONTINUED
7.1 R6 - R8, R29 - R34 (270 Ω)
R24, R25, R28 (4.7 KΩ)
7.2 Q2, Q11, Q12, Q13 (MPS 42)
7.3 R26, R27 (390 KΩ)
7.4 C7, C9, C10 (100nF)
C8 (0.1F or 0.22F)
Ensure the arrows on C8 are aligned with the corresponding arrows
on the PCB
7.5 SET, DJ, L RM, DST (Switches)
D6, D7 (5mm Yellow LED)
D8 (5mm Green LED)
LS1 (Piezo Buzzer)
GPS / RFT (3.5mm Jack Socket)
Install the 5mm EDs touching the PCB, NOT level with the
switches. This will ensure a perfect fit with our Acrylic case.

Nixie Tube Clock 'IN-8 & NL840 Nixie'
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www.pvelectronics.co.uk
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7.6 M, PM Neon Indicators
It is a good idea to install these components at the very end of the
assembly, when you have a better idea of a suitable height that
will look perfect with your design of case. So, do not install them
now but remember to install them some time later! Use small
pieces of the clear insulation supplied to prevent shorts on the
leads.