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TUCSON AMATEUR PACKET RADIO
Packet Radio
Terminal Node Controller
TNC 2, Rev 2
ASSEMBLY MANUAL
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
Copyright (c) 1985, 1991
Tucson Amateur Packet Radio Corporation
P.O. Box 12925
Tucson, AZ 85749
(602) 749-9479
FAX (602) 749-5636
All rights reserved.
Reproduction or translation of any part of this work beyond that
permitted by Sections 107 or 108 of the 1976 United States
Copyright Act (or its legal successor) without the express
permission of the copyright owner is unlawful except as noted
below. Requests for permission to copy or for further
information should be addressed to Tucson Amateur Packet Radio
Corporation.
Except as noted above, permission is hereby granted to any
non-profit group or individual to reproduce any portion of this
document provided that: the reproduction is not sold for profit;
the intent of the reproduction is to further disseminate
information on packet radio; the reproduction is not used for
advertising or otherwise promoting any specific commercial
product; and full credit is given to Tucson Amateur Packet Radio
Corporation (including address) as the original source of
information.
June 1985
Revised June 1991
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
SPECIAL EDITION FOR ASSEMBLY OF PC BOARDS
EXCLUSIVE OF THE COMPLETE KIT
1991
The information contained in this document has been carefully
checked and is believed to be entirely reliable. However, no
responsibility is assumed for inaccuracies. Tucson Amateur
Packet Radio Corporation (TAPR) reserves the right to make
changes to any products to improve reliability, function or
design without obligation to purchasers of previous equipment.
TAPR does not assume any liability arising out of the application
or use of any product or circuit described herein; neither does
it convey any license under its patent rights or the rights of
others.
This document was originally prepared for assembly of the TAPR
TNC 2 kits. These kits are no longer available from TAPR, nor
are any of the parts, with the exception of programmed EPROMS for
the state machine and firmware. This document has been revised
for use with bare printed circuit boards furnished by TAPR. Some
of the assembly techniques described and parts shown may be
unique to the parts contained in the TAPR TNC 2 kit. This does
not imply that substitutions are not possible, however TAPR has
not evaluated all of the possible effects of parts substitution,
and assumes no responsibility for any peculiarities in
performance. In selecting parts for use with these boards, you
should become familiar with both the layout of the board itself
and the assembly techniques described herein, in selecting the
proper part for the application, prior to assembly. Included in
the revision is the deletion of the MF-10 switched capacitor
filter, which results in increased dynamic range for the XR2211
demodulator and the upgrade to 32K RAM, which was not part of the
original kit, but is required for use with the current version of
TAPR firmware. In addition, it is HIGHLY RECOMMENDED that you
modify the DCD circuit as described by Eric Gustafson, N7CL in an
article published in the Proceedings of the 7th ARRL Computer
Networking Conference (American Radio Relay League, 225 Main
Street, Newington, CT 06111). TAPR offers a kit for this purpose
which makes the modification fairly painless.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
Parts List
Resistors
1/4 watt, 5%
( ) 1 47 ohm (yellow-violet-black-gold)
( ) 6 100 ohm (brown-black-brown-gold)
( ) 1 200 ohm (red-black-brown-gold)
( ) 5 470 ohm (yellow-violet-brown-gold)
( ) 1 560 ohm (green-blue-brown-gold)
( ) 7 1k ohm (brown-black-red-gold)
( ) 2 4.7k ohm (yellow-violet-red-gold)
( ) 1 5.6k ohm (green-blue-red-gold)
( ) 26 10k ohm (brown-black-orange-gold)
( ) 1 27k ohm (red-violet-orange-gold)
( ) 4 47k ohm (yellow-violet-orange-gold)
( ) 15 100k ohm (brown-black-yellow-gold)
( ) 1 150k ohm (brown-green-yellow-gold)
( ) 2 470k ohm (yellow-violet-yellow-gold)
( ) 1 510k ohm (green-brown-yellow-gold)
( ) 3 1M ohm (brown-black-green-gold)
1/8 watt, 1%
( ) 1 16.2k ohm (brown-blue-red-red-brown)
( ) 1 22.1k ohm (red-red-brown-red-brown)
( ) 1 30.1k ohm (orange-black-brown-red-brown)
( ) 1 47.5k ohm (yellow-violet-green-red-brown)
( ) 1 100.k ohm (brown-black-black-orange-brown)
Trimpots
( ) 2 10k ohm (3299W-10K)
( ) 1 20k ohm (3299W-20K)
( ) 1 50k ohm (3299W-50K)
Capacitors
Mylar or Monolithic
( ) 1 10 pF (10, 10J or 100)
( ) 1 100 pF (101)
( ) 1 220 pF (221)
( ) 1 0.001 uF (.001 or 102)
( ) 1 0.0015 uF (.0015 or 152)
( ) 1 0.0022 uF (.0022 or 222)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) 1 0.0047 uF (.0047 or 472)
( ) 8 0.01 uF (.01 or 103)
( ) 2 0.022 uF (.022 or 223)
( ) 29 0.1 uF (.1 or 104)
( ) 1 0.15 uF (.15 or 154)
Electrolytic (and Trimmer)
The electrolytic capacitors may have voltage ratings equal to or
greater than those listed below, but not less.
( ) 1 1 uF, 16v Radial TANTALUM
( ) 4 1 uF, 16v Radial
( ) 8 10 uF, 16v Radial
( ) 1 100 uF, 16v Radial
( ) 1 1000 uF, 16v Axial
( ) 1 60 pF Trimmer
Integrated Circuits
Integrated circuits may come from various manufacturers and may
have differing prefixes and/or suffixes. For example, if the
part is listed as a 74LS00, it may be marked SN74LS00N or
MC74LS00P or DM74LS00N or F74LS00P or a similar variation. The
key is that the sequence 74LS00 appears in the part number. A
four-digit number, such as 8515, indicates the year and week of
manufacture and should not be confused with the part number.
Typical parts are shown in many instances.
WARNING: Exercise extreme caution when handling ICs. They
should be kept in a black foam carrier or other anti-static
protective container until you are ready to install them. This
precaution cannot be overemphasized!
( ) 1 324 Quad Op Amp LM324
( ) 1 358 Dual Op Amp LM358
( ) 1 556 Oscillator/Timer LM556
( ) 1 2206 FSK Generator XR2206
( ) 1 2211 PLL Demodulator XR2211
( ) 1 2764/27C64 EPROM, Programmed, "STATE MACHINE"
( ) 1 27C256 CMOS EPROM, Programmed, "TAPR FIRMWARE"
( ) 1 32K CMOS Static RAM 43256C-15L
( ) 1 8440/84C40 SIO/0 Dual Serial Port Z8440
( ) 1 84C00 or 70008 CMOS Z80 CPU Z84C00
( ) 1 4040 CMOS Divider CD4040B
( ) 1 74HC4066 Quad CMOS Switch 74HC4066
( ) 1 74HCT04 Hex Inverter 74HCT04
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) 3 74HC14 Hex Schmitt Inverter 74HC14
( ) 1 74HC/HCT107 Dual J-K Flip Flop 74HC107
( ) 1 74HC/HCT139 Dual Decoder 74HC139
( ) 1 74HCT374 Octal Latch 74HCT374
( ) 1 74HC/HCT393 Dual Binary Divider 74HC393
Sockets
( ) 1 08-pin DIP Socket
( ) 11 14-pin DIP Socket
( ) 5 16-pin DIP Socket
( ) 1 20-pin DIP Socket
( ) 3 28-pin DIP Socket
( ) 2 40-pin DIP Socket
Connectors
( ) 5 2-pin male header
( ) 2 3-pin male header
( ) 1 5-pin male header with "wall"
( ) 1 14-pin male DIP header
( ) 1 16-pin male DIP header
( ) 1 5-pin DIN female, PC right angle
( ) 1 5-pin DIN male, cable type, with boot *
( ) 1 DB25S 25-pin female PC right angle
( ) 1 2.1mm Power PC right angle
( ) 1 2.1mm Power Cable w/connector
( ) 3 Jumper, Push-On
* The DIN5-180P consists of the following items:
1 Body, Connector
1 Boot, Insulating
1 Shield, Upper, Metal
1 Shield, Lower, Metal
1 Ferrule, Metal
5 Pins, Male
Diodes
( ) 2 1N754, Zener, 6.8v
( ) 6 1N4001, Rectifier, 1A
( ) 7 1N4148, Switching
( ) 1 1N4746, Zener, 18v
( ) 1 1N4752, Zener, 36v
( ) 5 LED, Red, Rectangular
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
Transistors and Voltage Regulator
( ) 1 TX101 or VN10KM VFET
( ) 9 2N3904 NPN Switching
( ) 3 2N3906 PNP Switching
( ) 1 7805CT +5v Regulator
Miscellaneous
( ) 2 4-40 x 3/8 screw
( ) 2 #4 Star Washer, Internal Tooth
( ) 2 4-40 hex nut
( ) 1 DIP Switch, 8-position, Right Angle
( ) 1 Switch, DPDT, Push-On/Push-Off
( ) 1 Cap, Grey, Push Button
( ) 1 4.9152 MHz Crystal, HC-18/U
( ) 1 10 uH inductor, molded,large
( ) 2 10 uH inductor, molded, small
( ) 5 Self-tapping screws, Phillips head
( ) 4 Stick-on rubber feet
( ) 1 Clip-on Heat Sink
( ) 1 Shielded Jumper Wire
( ) 1 Battery, Lithium, 3-volt
NOTE: The Lithium battery used in TNC 2 must be
handled with extreme care. NEVER ALLOW A SHORT
CIRCUIT ACROSS THE BATTERY TERMINALS OR THE
BATTERY COULD EXPLODE AND CAUSE SERIOUS INJURY!
Leave the battery in its envelope until called for
in the instructions.
( ) 1 Printed Circuit Board, TNC 2, Rev 3
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
TAPR TNC 2 Assembly Directions
This section will proceed in a step-by-step fashion. Please
mount and solder the components to the board in the order given.
It has been tested on numerous units and found to be a very
efficient order for assembly.
When mounting axial lead discrete components, such as resistors
and certain diodes, grasp the body of the part in one hand and
bend the leads of the device with the other, such that the leads
will pass through the holes provided on the board. Note that all
axial lead components (except C12 and R80) are on 0.5 inch lead
centers. Place the part so the body is parallel to, and flat
against, the circuit board unless instructed otherwise. Next,
bend the leads on the bottom of the board slightly to secure the
part. Then proceed to mount the next component. Do not solder
the part until directed.
NOTE: The tab of regulator Q3 (7805CT) can be used as a bending
jig! Simply place the resistor or diode across the tab on Q3 and
form the leads around the tab. The leads will then be spaced at
0.5".
Soldering
When soldering parts to the printed circuit board, use only a
very small tipped controlled temperature (700 degrees F., 371
degrees C. maximum) soldering iron and fine (.050 inch)
rosin-core solder. 63/37 (eutectic) solder is preferred, but
60/40 is acceptable.
To ensure the joint is properly soldered, the iron should be
placed so that it contacts the pad on the board and the lead to
be soldered. Solder should then be applied to the pad and the
opposite side of the lead from the iron. Thus, the iron must
heat both the pad and the lead to cause the solder to melt. This
helps prevent cold solder joints. Also, keep a wet sponge handy
and wipe the soldering iron tip on it frequently to keep it (and
your connections) clean.
Care must be taken to ensure that the pad is not overheated, or
it may lift from the PC board! Apply heat only when ready to
solder. Do not apply heat longer than necessary to complete a
good joint, but be sure to heat adequately for the solder to flow
completely.
NOTE: All modern components are designed for soldering and you
should not worry about 5-10 seconds of heating.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
Board Mapping
Place the circuit board on a clean working surface. Orient the
board so the lettering is in normal reading position. For
purposes of description, the board consists of four sectors. The
top of the board is the edge nearest the large axial capacitor
(C12). The bottom, left and right follow in natural order. The
upper left is quadrant one, the upper right is quadrant two, the
lower left is quadrant three and the lower right is quadrant
four. The board assembly will proceed by quadrants.
Board Modification
The TNC 2 was originally designed to use two (2) 6264 static RAM
ICs, giving a total memory of 16K. TAPR firmware revisions 1.1.4
and later require 32K of RAM. This uses a single 32K RAM chip
(U24 is not used). This changes requires a slight modification
to the PC board.
( ) Locate JMP12 on the board. It is in quadrant 2 near the
bottom and to the right of U6 with the board oriented as
described above.
( ) Turn the board over so that the circuit side can be
seen. There is a trace connecting the top and center pads of
JMP12. Cut this trace.
( ) Add a jumper between the bottom and center pads of
JMP12.
( ) Turn the board over again so that it is in the position
described above.
IC Sockets
NOTE: If any socket pins are bent, carefully straighten them
with a pair of long-nose pliers.
When installing IC sockets, tack-solder two diagonally opposite
corners first (such as pin 1 and pin 8 on a 14-pin socket).
Double check to ensure that the socket is seated properly against
the board with the notch, bevelled corner or "1" nearest pin 1
(pin 1 is the upper left corner when viewed from the component
side of the board on all socketed ICs) and that all IC socket
pins are showing on the solder side of the board. Then solder
the remaining pins of that socket before proceeding to the next
one.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
NOTE: Take care now to avoid solder bridges!
If you find a socket is difficult to install, remove it, as you
are probably bending a pin!
Now begin installing sockets.
(quadrant 1)
( ) U1 16-pin
( ) U2 14-pin
( ) U7 14-pin
( ) U8 8-pin
( ) U3 14-pin
( ) U9 14-pin
(quadrant 2)
( ) U4 14-pin
( ) U10 14-pin
( ) U11 14-pin
( ) U5 20-pin
( ) U6 28-pin
(quadrant 3)
( ) U15 14-pin
( ) U16 16-pin
( ) U19 16-pin
( ) U20 14-pin
(quadrant 4)
( ) U21 40-pin
( ) U22 40-pin
( ) U12 16-pin
( ) U13 14-pin
( ) U14 14-pin
( ) U23 28-pin
( ) U25 28-pin
Now check your work. All leads should be soldered. There should
be no solder bridges (a blob of solder that shorts two adjacent
soldered connections) or cold (grey and/or grainy-looking) solder
connections. The positions on the printed circuit board for U17,
U18 and U24 will be empty. You should have one (1) 16-pin IC
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
socket remaining.
( ) OK so far.
Since we have deleted the MF10 switched capacitor filter, a
jumper must be connected to route the received audio signal to
the demodulator.
( ) Solder an insulated wire from the plated through holes
of U17 pin 8 to U18 pin 1 (no sockets are mounted in these
positions).
Resistors
Install the following 5% resistors on the board:
(quadrant 1)
( ) R1 47 ohm (yellow-violet-black-gold)
( ) R2 10k ohm (brown-black-orange-gold)
( ) R3 100k ohm (brown-black-yellow-gold)
( ) R5 100k ohm (brown-black-yellow-gold)
( ) R7 10k ohm (brown-black-orange-gold)
( ) R8 1k ohm (brown-black-red-gold)
WARNING: Be careful when clipping leads, as they may have a
tendency to fly towards your eyes! Take appropriate precautions
(grasp leads and provide eye protection).
( ) Solder and clip the leads (12 total)
( ) R14 100 ohm (brown-black-brown-gold)
( ) R15 100 ohm (brown-black-brown-gold)
( ) R16 100 ohm (brown-black-brown-gold)
( ) R17 100 ohm (brown-black-brown-gold)
( ) R18 100 ohm (brown-black-brown-gold)
( ) R19 100 ohm (brown-black-brown-gold)
( ) R20 100k ohm (brown-black-yellow-gold)
( ) R21 100k ohm (brown-black-yellow-gold)
( ) R22 10k ohm (brown-black-orange-gold)
( ) R23 10k ohm (brown-black-orange-gold)
( ) R6 100k ohm (brown-black-yellow-gold)
( ) Solder and clip leads (22 total)
( ) R24 100k ohm (brown-black-yellow-gold)
( ) R25 27k ohm (red-violet-orange-gold)
( ) R26 10k ohm (brown-black-orange-gold)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) R27 100k ohm (brown-black-yellow-gold)
( ) R28 10k ohm (brown-black-orange-gold)
( ) Solder and clip leads (10 total)
( ) R36 1k ohm (brown-black-red-gold)
( ) R37 100k ohm (brown-black-yellow-gold)
( ) R38 10k ohm (brown-black-orange-gold)
( ) R39 150k ohm (brown-green-yellow-gold)
( ) R40 100k ohm (brown-black-yellow-gold)
( ) R41 470k ohm (yellow-violet-yellow-gold)
( ) Solder and clip leads (12 total)
( ) R42 100k ohm (brown-black-yellow-gold)
( ) R43 100k ohm (brown-black-yellow-gold)
( ) R44 47k ohm (yellow-violet-orange-gold)
( ) R45 47k ohm (yellow-violet-orange-gold)
( ) R46 1k ohm (brown-black-red-gold)
( ) R47 1k ohm (brown-black-red-gold)
( ) R48 1k ohm (brown-black-red-gold)
( ) Solder and clip leads (14 total)
(quadrant 2)
( ) R9 10k ohm (brown-black-orange-gold)
( ) R10 10k ohm (brown-black-orange-gold)
( ) R11 1k ohm (brown-black-red-gold)
( ) R12 10k ohm (brown-black-orange-gold)
( ) R13 47k ohm (yellow-violet-orange-gold)
( ) Solder and clip leads (10 total)
( ) R29 10k ohm (brown-black-orange-gold)
( ) R30 10k ohm (brown-black-orange-gold)
( ) R31 100k ohm (brown-black-yellow-gold)
( ) R32 4.7k ohm (yellow-violet-red-gold)
( ) R33 1k ohm (brown-black-red-gold)
( ) R34 470 ohm (yellow-violet-brown-gold)
( ) R35 470 ohm (yellow-violet-brown-gold)
( ) Solder and clip leads (14 total)
(quadrant 3)
( ) R55 10k ohm (brown-black-orange-gold)
( ) R56 5.6k ohm (green-blue-red-gold)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) R57 560 ohm (green-blue-brown-gold)
( ) R58 1 Megohm (brown-black-green-gold)
( ) R59 1 Megohm (brown-black-green-gold)
( ) Solder and clip leads (10 total)
( ) R60 200 ohm (red-black-brown-gold)
( ) R61 10k ohm (brown-black-orange-gold)
( ) R62 47k ohm (yellow-violet-orange-gold)
( ) R64 100k ohm (brown-black-yellow-gold)
( ) R65 100k ohm (brown-black-yellow-gold)
( ) Solder and clip leads (10 total)
( ) R67 10k ohm (brown-black-orange-gold)
( ) R68 10k ohm (brown-black-orange-gold)
( ) R69 10k ohm (brown-black-orange-gold)
( ) R70 10k ohm (brown-black-orange-gold)
( ) Solder and clip leads (8 total)
( ) R71 10k ohm (brown-black-orange-gold)
( ) R72 100k ohm (brown-black-yellow-gold)
( ) R73 470k ohm (yellow-violet-yellow-gold)
( ) R74 10k ohm (brown-black-orange-gold)
( ) R98 4.7k ohm (yellow-violet-red-gold)
( ) Solder and clip leads (10 total)
(quadrant 4)
( ) R49 10k ohm (brown-black-orange-gold)
( ) R50 10k ohm (brown-black-orange-gold)
( ) R51 10k ohm (brown-black-orange-gold)
( ) R96 10k ohm (brown-black-orange-gold)
( ) R97 470 ohm (yellow-violet-brown-gold)
( ) R52 10k ohm (brown-black-orange-gold)
( ) R53 470 ohm (yellow-violet-brown-gold)
( ) R54 470 ohm (yellow-violet-brown-gold)
( ) R75 10k ohm (brown-black-orange-gold)
( ) Solder and clip leads (18 total)
There should be two 5% resistors remaining, one 510k (green brown-yellow-gold), and one 1 Megohm (brown-black-green- gold).
( ) Two 5% resistors remaining.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
The following devices are trimpots. When you install one, tack
solder the center lead to the PC board. Do not solder the other
leads, nor clip any leads, until directed. This enables you to
line up all the trimpots neatly before you commit any of them to
a "final" position.
NOTE: Orient each trimpot with the adjustment screw toward the
left edge of the board.
(quadrant 3 only)
( ) R76 50k
( ) R77 10k
( ) R78 20k
( ) R79 10k
( ) Line up R76-79.
( ) Solder and clip leads (12 total)
Now check your work. All leads should be soldered and clipped
close to the bottom of the PC board. You should have all
thirteen 1% and two 5% resistors remaining. There should be no
solder bridges nor cold solder connections.
( ) OK so far.
Diodes
WARNING: Diodes are polarized! The marked (banded or tapered)
end of the diodes (cathode) should match the banded end of the
silk screen. You may need to use a magnifying glass to read the
diode part numbers.
(quadrant 1)
( ) CR22 1N4001 (cathode to the top of the board)
( ) CR1 1N4746 (cathode to the top of the board)
( ) CR2 1N4001 (cathode to the top of the board)
( ) CR3 1N4001 (cathode to the top of the board)
( ) CR4 1N4001 (cathode to the top of the board)
( ) CR5 1N4001 (cathode to the top of the board)
( ) CR6 1N754 (cathode to the bottom of the board)
( ) Solder and clip leads (14 total)
( ) CR9 1N4148 (cathode to the top of the board)
( ) CR13 1N4148 (cathode to the left of the board)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) CR10 1N4148 (cathode to the bottom of the board)
( ) Solder and clip leads (6 total)
( ) Save one of the clipped 1N4148 leads for use during
modem calibration.
(quadrant 2)
( ) CR7 1N4001 (cathode to the top of the board)
( ) CR8 1N754 (cathode to the top of the board)
( ) CR11 1N4148 (cathode to the top of the board)
( ) CR16 1N4148 (cathode to the top of the board)
( ) Solder and clip leads (8 total)
NOTE: The LEDs will be installed later.
(quadrant 3)
( ) CR12 1N4752 (cathode to the top of the board)
( ) CR14 1N4148 (cathode to the top of the board)
( ) CR15 1N4148 (cathode to the top of the board)
( ) Solder and clip leads (6 total)
(quadrant 4 -- none)
Now check your work. You should have 5 LEDs remaining. All
leads should be soldered and clipped close to the bottom of the
PC board. There should be no solder bridges nor cold solder
connections.
( ) OK so far.
Capacitors
WARNING: The electrolytic capacitors are polarity sensitive.
The silk screen indicates the positive lead, while most
electrolytic capacitors have the negative lead marked. Be
careful to ensure the parts are correctly installed or damage may
occur at power up!
NOTE: All capacitors, especially electrolytic, should be mounted
as nearly flush to the surface of the PC board as practical
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
without overstressing the leads.
(quadrant 1)
( ) C1 0.1 uF (104)
( ) C2 0.01 uF (103)
( ) C3 10 uF 16v radial electrolytic
( ) C4 0.1 uF (104)
( ) C5 0.001 uF (102)
( ) C6 10 uF 16v radial electrolytic
( ) C7 10 uF 16v radial electrolytic
( ) C58 1 uF 16v radial electrolytic
( ) C10 10 uF 16v radial electrolytic
( ) C11 0.1 uF (104)
( ) Solder and clip leads (20 total)
( ) C31 10 uF 16v radial electrolytic
( ) C56 0.1 uF (104)
( ) C32 0.1 uF (104)
( ) C21 0.1 uF (104)
( ) C22 10 uF 16v radial electrolytic
( ) C23 0.1 uF (104)
( ) C59 0.01 uF (103)
( ) C24 0.01 uF (103)
( ) C51 10 pF (10 or 100)
( ) Solder and clip leads (18 total)
(quadrant 2)
( ) C8 10 uF 16v radial electrolytic
( ) C9 0.1 uF (104)
( ) C60 220 pF (221)
( ) C13 0.1 uF (104)
( ) C14 0.1 uF (104)
( ) C25 0.1 uF (104)
( ) C26 0.1 uF (104)
( ) C61 100 pF (101)
( ) Solder and clip leads (16 total)
( ) C12 1000 uF25v axial electrolytic
( ) Solder and clip leads (2 total)
( ) C15 0.1 uF (104)
( ) C17 0.1 uF (104)
( ) C19 0.01 uF (103)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) C20 1 uF radial TANTALUM (105) (+ to bottom of board)
( ) C18 10 uF 16v radial electrolytic
( ) C16 100 uF 16v radial electrolytic
( ) Solder and clip leads (12 total)
(quadrant 3)
( ) C33 1 uF 16v radial electrolytic
( ) C34 1 uF 16v radial electrolytic
( ) C35 0.01 uF (103)
( ) C57 0.1 uF (104)
( ) C36 0.0015 uF (152)
( ) C37 0.1 uF (104)
( ) C38 0.1 uF (104)
( ) Solder and clip leads (14 total)
( ) C39 0.01 uF (103)
( ) C40 0.1 uF (104)
( ) C41 0.1 uF (104)
( ) C42 0.01 uF (104)
( ) C43 0.1 uF (104)
( ) C44 1 uF 16v radial electrolytic
( ) C45 0.15 uF (154)
( ) C46 0.1 uF (104)
( ) Solder and clip leads (16 total)
( ) C47 60pF trimmer capacitor
( ) C48 0.1 uF (104)
( ) Solder and clip leads (2 total - none on trimmer)
(quadrant 4)
( ) C27 0.1 uF (104)
( ) C28 0.1 uF (104)
( ) C29 0.1 uF (104)
( ) C30 0.1 uF (104)
( ) C49 0.1 uF (104)
( ) C50 0.1 uF (104)
( ) Solder and clip leads (12 total)
You should have six (6) monolithic capacitors remaining: one each
of 0.0022 uF (222), 0.0047 uF (472), 0.01 uF (103) and 0.1 uF
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
(104); and two each of 0.022 uF (223).
( ) 6 capacitors remaining.
Now check your work. All leads should be soldered and clipped
close to the bottom of the PC board. There should be no solder
bridges nor cold solder connections.
( ) OK so far.
Transistors
NOTE: Transistors have three leads and are polarity sensitive!
Be sure to properly match the transistor outline with the
silkscreened image on the PC board. The transistors have a flat
side and the directions will call out the orientation of this
outline as an additional precaution. When installing a
transistor, be careful not to overheat the device.
Before installing a transistor, carefully bend the center lead
away from the flat side of the transistor body and slightly
spread the two outside leads apart.
(quadrant 1)
( ) Q8 2N3906 (Flat side to the left edge.)
( ) Q9 2N3904 (Flat side to the left edge.)
( ) Solder and clip leads (6 total)
(quadrant 2)
( ) Q1 2N3904 (Flat side to the lower edge.)
( ) Q2 2N3904 (Flat side to the left edge.)
( ) Solder and clip leads (6 total)
( ) Q4 2N3904 (Flat side to the lower edge.)
( ) Q5 2N3906 (Flat side to the lower edge.)
( ) Solder and clip leads (6 total)
( ) Q6 2N3904 (Flat side to the lower edge.)
( ) Q7 2N3904 (Flat side to the left edge.)
( ) Solder and clip leads (6 total)
( ) Q15 2N3904 (Flat side to the lower edge.)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) Solder and clip leads (3 total)
(quadrant 3)
( ) Q10 VN10KM/TX101 (Flat side to the left edge.)
( ) Q12 2N3906 (Flat side to the right edge.)
( ) Solder and clip leads (6 total)
( ) Q13 2N3904 (Flat side to the right edge.)
( ) Q14 2N3904 (Flat side to the right edge.)
( ) Solder and clip leads (6 total)
(quadrant 4 -- none)
You should have no transistors (but one voltage regulator)
remaining.
( ) No transistors remaining.
Remaining Components
NOTE: In the following steps you will complete soldering parts
on the TAPR TNC 2 printed circuit board. Solder each component
as you install it in this assembly phase. Be sure to proceed
carefully and continue to exercise good workmanship!
(quadrant 1)
( ) SW1 Locate the DPDT Power switch. Note that it has two
sets of contacts; one set consists of 6 pins while the other set
consists of 6 lugs with holes in them.
( ) Carefully install SW1 on the PC board with the white
plastic actuator extending over the left edge of the PC board.
Be sure the switch is "square" with the PC board and resting on
the small legs protruding from the switch bottom.
( ) Clip off the 6 (six) lugs on the top of SW1.
( ) Now firmly press on the grey cap on the power switch
shaft. The cap should be horizontal, that is, parallel to the PC
board. Press it on until it "snaps" in place on the switch
shaft.
( ) P1 Locate the 2.1mm Power Connector. This device has
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
three lugs on the bottom surface and one lug on the top surface.
( ) Install P1 on the PC board. Be sure it rests firmly on
the PC board surface.
( ) Clip off the lug on the top of P1.
( ) SW2 Install the 8 pole DIP switch. Note that SW2
"rides" about 1/16" (1.6 mm) above the surface of the PC board.
( ) BE SURE THAT ALL SWITCHES OF SW2 ARE IN THE OFF
POSITION (or you may cause damage to integrated circuit U1 in a
later step)!
NOTE: When installing jumper strips, be sure that the shorter
pins are soldered to the PC board and the longer pins stick up.
WARNING: Don't grip jumpers with your fingers while soldering.
The pins quickly get very hot!
( ) JMP4 Install a 2-pin header.
( ) L2 10 uH choke (this is one of the smaller chokes)
(quadrant 2)
( ) L1 10 uH choke (this is the larger choke)
( ) JMP5 Install a 2-pin header.
( ) Q3 Place the 7805CT regulator at location Q3, with the
metal tab side of the part away from the near (right) edge of the
PC board (do not solder yet).
( ) Using one of the #4 black self-tapping screws, secure
Q3 to the case or other heat sink. Be sure it is vertical, and
that the leads are passing through the corresponding holes in the
PC board.
( ) Solder the three leads of Q3 in place.
( ) Now unscrew Q3 and remove the PC board from the case.
Set the case aside until called for later.
( ) Trim the leads on Q3.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
(quadrant 3)
( ) J1 25-pin female DB-25 connector. Attach this
connector with two 4-40 x 3/8 screws, #4 lockwashers and 4-40
nuts. The screw heads should be on the solder side of the PC
board. Be careful not to damage the traces near the power switch
end of the connector. Be sure to solder all 25 pins after
fastening this connector!
( ) J2 Install the 5-pin DIN connector.
( ) JMP7 Install a 2-pin male header
( ) JMP8 Install a 2-pin male header
( ) JMP9 Install two 3-pin male headers
( ) JMP10 Install a 2-pin male header
( ) J3 Install a 5-pin male header (wall toward U20)
( ) Y1 Install the 4.9152 MHz crystal (Do not overheat!)
(quadrant 2 and quadrant 4)
NOTE: When soldering the LEDs in place, use a pair of long-nose
pliers and carefully bend the leads at right angles so the LED
will lie flat on the PC board, with the shorter of the two leads
(cathode) towards the bottom edge of the board and the "lens" end
of the LED hanging over the right side of the PC board. The LED
leads should be bent at the point where the leads become narrow
after exiting the plastic body of the device. Solder and clip
both leads before proceeding to the next LED.
WARNING: When installing LEDS, do not spread the leads to secure
the LED to the board. Bending the leads can fracture the plastic
casing and cause the device to fail. Instead, hold the LED while
soldering it.
NOTE: Remember that all LEDs are oriented with the cathode
towards the bottom edge of the PC board. The LED cathode lead is
the shorter of the two.
( ) CR17 LED "PWR"
( ) Solder and clip leads (2 total)
( ) CR19 LED "CON"
( ) Solder and clip leads (2 total)
( ) CR18 LED "STA"
( ) Solder and clip leads (2 total)
( ) CR21 LED "PTT"
( ) Solder and clip leads (2 total)
( ) CR20 LED "DCD"
( ) Solder and clip leads (2 total)
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
Bottom of PC Board
There are two bypass capacitors, one rf choke and a shielded,
insulated jumper that mount on the underside of the PC board.
There are no silkscreened locations for these parts, so pay espe cially close attention to the schematic diagram and board layout.
( ) C63 0.1 uF (104) (at SW1)
( ) C62 0.01 uF (103) (at J2)
( ) L3 10 uH choke (this is a smaller choke) (at J1)
( ) Shielded jumper. Solder one end at the hole near
SW1.
( ) Shielded jumper. Solder the other end at the hole
near Q3.
Now lay the PC board aside and prepare to wire the DIP headers.
These are the devices that plug into an IC socket but have
notched pins above the plug to allow soldering discrete
components to the header.
NOTE: DO NOT overheat the headers when soldering or they may
deform! To help prevent heat damage to the header, put the extra
16-pin DIP socket in a vise and insert the header in the socket.
Then, solder the parts to the header.
U15
The following devices mount on a 14-pin DIP header, U15. Form
the leads on the parts so the components lay in the slots
provided on the top of the header. Solder the two leads, then
clip them flush with the sides of the post. Note the bevelled
corner or notch marking pin 1 of the header.
NOTE: The resistor in the next step is 5%.
( ) R83 1 Meg 5% (brown-black-green-gold)
(pins 3 and 12)
( ) C55 0.022 uF monolithic (223)
(pins 5 and 10)
( ) R81 16.2k 1% (brown-blue-red-red-brown)
(pins 6 and 9)
( ) R82 30.1k 1% (orange-black-brown-red-brown)
(pins 7 and 8)
( ) Set the header aside until it is called for later.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
U19
The following devices mount on a 16-pin DIP header, U19. Note
the bevelled corner or notch marking pin 1 of the header.
( ) C52 0.022 uF monolithic (223)
(pins 2 and 15)
( ) R92 22.1k 1% (red-red-brown-red-brown)
(pins 3 and 14)
( ) R93 47.5k 1% (yellow-violet-green-red-brown)
(pins 4 and 13)
( ) C53 0.0047 uF monolithic (472)
(pins 5 and 12)
( ) C54 0.0022 uF monolithic (222)
(pins 6 and 11)
( ) R94 100k 1% (brown-black-black-orange-brown)
(pins 7 and 10)
NOTE: The resistor in the next step is 5%.
( ) R95 510k (green-brown-yellow-gold)
(pins 8 and 9)
( ) Set the header aside until it is called for later.
( ) Discard the extra 16-pin socket.
Initial Checkout of TNC 2
For initial checkout you will need a voltmeter capable of
measuring up to 30 volts dc. If you encounter any problems, such
equipment as an ohmmeter, oscilloscope, and logic probe will
prove very useful.
NOTE: Be sure to insulate the TNC 2 PC board assembly from any
conductive work surface during testing!
( ) Locate the 2.1mm power connector/cable.
( ) Strip about 1/4" (0.6 cm) of insulation from each lead on the
free end of the cable.
NOTE: The power supply used should be current limited to or
fused for 500 mA.
( ) Connect the lead with a white stripe to a source of +10 to
+15 volts dc.
( ) Connect the other lead to the (-) return side of the +10 to
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
+15 volts dc power source.
( ) Depress the power switch on your TNC 2 a couple of times.
Note that it latches in two positions alternately.
( ) Cycle the power switch until it latches in the OFF (out)
position.
( ) Connect the 2.1mm power cable to P1.
In the following steps, power will be applied to your TNC. Be
ready to remove power quickly! If you smell anything that
resembles a burning TNC, remove power immediately.
If you have problems at any point, disconnect power and determine
the cause of the problem before proceeding!
( ) With power switch SW1 still in the out, or OFF position,
apply 10 to 15 volts dc to the power cable.
( ) Using an accurate dc voltmeter, measure the voltage
between ground (at - lead of C12 in quadrant 2) and either of the
lug stubs on top of switch SW1 nearest the push button. Record
the voltage in the space below.
(Measured value: ___________________________)
( ) If the voltage recorded in the step above is below +10v,
greater than +15v or is negative, take corrective action. DO NOT
PROCEED UNTIL THIS MEASUREMENT IS CORRECT OR YOU MAY CAUSE
SERIOUS DAMAGE TO YOUR TNC 2!
( ) Switch SW1 to the in, or ON position. The PWR, PTT and
DCD LEDs should glow.
( ) Measure the voltage at the input side of Q3. This is
the lead closest to LED CR17 (PWR). BE CAREFUL TO NOT SHORT THE
INPUT LEAD TO ANYTHING WHILE MAKING THIS MEASUREMENT!
(Measured value: ___________________________)
( ) The voltage measured in the above step should be no more
than 2 volts below the input voltage measured earlier. DO NOT
PROCEED UNTIL THIS MEASUREMENT IS CORRECT OR YOU MAY CAUSE
SERIOUS DAMAGE TO YOUR TNC 2!
( ) Measure the voltage at the output side of Q3. This is
the lead farthest from LED CR17. BE CAREFUL TO NOT SHORT THE
OUTPUT LEAD TO ANYTHING WHILE MAKING THIS MEASUREMENT!
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
(Measured value: ___________________________)
( ) The voltage measured in the above step should be between
+4.7 and +5.3 volts dc. DO NOT PROCEED UNTIL THIS MEASUREMENT IS
CORRECT OR YOU MAY CAUSE SERIOUS DAMAGE TO YOUR TNC 2!
( ) Switch SW1 to the out, or OFF position.
At this point, your TNC 2 positive voltage supply is checked and
verified. If the above tests were not successful, refer to the
Troubleshooting chapter of the TNC 2 System Manual for help. In
the following steps you will verify the operation of the negative
supplies used in the modem and computer interface circuits.
First, however, it is necessary to review proper IC handling
procedures.
IC Installation
The ICs should be shipped to you in an anti-static carrier. Many
of them are VERY sensitive to static discharge. The probability
of them being defective as shipped is extremely low. They should
be handled with extreme care. If you live in a climate with low
humidity, or if you have carpeting in your work area, take
special precautions. You might try spraying the carpet with some
sort of fabric softener/anti-static preparation (such as a 50%
solution of "Downy" and water) to reduce static.
If you have a metal working surface, ground it! Place a hand on
the working surface before you touch the ICs and be sure to
frequently ground yourself to the working surface. If you don't
have such a surface, use a large cookie sheet or aluminum foil.
Handle ICs only while sitting quietly, never while moving or
walking!
Avoid static discharge near the ICs!
( ) Anti-static precautions understood and implemented.
Install the ICs using special IC handling tools, such as those
produced by OK Machine Tool. If you lack these, you may gently
rock both sides of an IC on your metal work surface to make the
leads straight and parallel to each other and install it in its
socket with firm, even pressure applied over the length of the IC
body.
WARNING: The TNC circuit board may flex excessively (when
installing ICs) if it is laid on a hard, flat surface, due to the
mounting screws on J1 and the components on the bottom of the PC
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
board. Do not allow the board to flex when inserting ICs.
If you make a mistake, or have to remove an IC for any reason,
special anti-static removal tools are available. If you don't
have access to such tools, you may try using a small screwdriver
and gently pry the IC out of the socket, a little at a time, from
alternate ends of the IC, but to use other than the proper tools
exposes you to risking damage to your IC.
NOTE: It is very easy to bend a pin or fold it under the IC
during installation. Be sure to check each IC as you install it
in the steps below to be sure that all pins are actually in the
socket and not tucked under the IC or hanging over the socket!
It is easy to make this error!
Now you may begin.
( ) Locate the LM556 IC.
( ) Install this IC in socket U2. Be careful to ensure that
no leads are bent. Pin 1 of this IC goes to the upper left
corner of the socket (as do all pin 1s on all ICs).
( ) Switch SW1 to the in, or ON position.
( ) Measure the voltage between ground (the negative lead
of C12) and the top end of R14 in quadrant 1. This is the end of
R14 immediately adjacent to socket IC1 pin 9.
(Measured value: ___________________________)
( ) The voltage measured in the above step should be more
negative than -6 volts. For a +12 volt input to TNC 2, it will
typically measure around -11 v (around -7.5 v when all ICs are
later installed). DO NOT PROCEED UNTIL THIS MEASUREMENT IS
CORRECT OR YOU MAY CAUSE SERIOUS DAMAGE TO YOUR TNC 2!
( ) Switch SW1 to the out, or OFF position.
( ) Locate the LM324 IC
( ) Install this IC in socket U3. Be careful to ensure that
no leads are bent. Pin 1 of this IC goes to the upper left
corner of the socket (as do all pin 1s on all ICs).
( ) Switch SW1 to the in, or ON position.
( ) Measure the voltage at the end of R5 nearest the edge of
the PC board in quadrant 1.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
(Measured value: ___________________________)
( ) The voltage measured in the above step should be between
- 4.7v and -5.3v. DO NOT PROCEED UNTIL THIS MEASUREMENT IS
CORRECT OR YOU MAY CAUSE SERIOUS DAMAGE TO YOUR TNC 2!
( ) Switch SW1 to the out, or OFF position.
You have now verified the operation of all the power supplies of
your TNC 2. Once again, check for any loose wire clippings,
solder splashes or other possible problem areas on your TNC 2.
( ) OK so far.
In the next steps you will be installing the digital ICs on your
TNC 2. Exercise extreme care when handling the ICs!
Install the following ICs:
(quadrant 1)
( ) U1 CD4040
( ) U7 74HC14
( ) U8 LM358
( ) U9 74HC14
(quadrant 2)
( ) U4 74HCT393
( ) U5 74HCT374
( ) U6 2764 (or 27C64) "STATE MACHINE"
( ) U10 74HCT04
( ) U11 74HC107
(quadrant 3 - none)
(quadrant 4)
( ) U21 8440 (or 84C40)
( ) U22 84C00
( ) U12 74HCT139
( ) U13 74HC4066
( ) U14 74HC14
( ) U23 27C256
( ) U25 43256C-15L
Double check to be sure that all ICs are in their correct sockets
and that there are no bent or tucked under leads. Pin 1 of all
ICs should be at the upper left corner.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) All ICs installed correctly.
You should have two ICs remaining (XR2206, XR2211) and all three
headers. These will be installed later.
( ) Three ICs and three headers remaining.
( ) Carefully inspect all ICs again to be sure they are all
seated in their sockets and there are no bent or otherwise
improperly installed pins. Be sure pin 1 of each IC matches pin
1 of its socket or you may destroy the IC.
( ) Attach a clip-on heat sink to Q3.
The next step will be to apply power to your TNC 2. Exercise
care and be ready to remove power the instant any problems
appear. Remember, if you let all the smoke out of a part during
these tests, it may never work properly again! If it is working
properly, you will see a certain sequence of LED activity.
Please read the following five steps before you perform any of
them!
( ) Read the following 4 steps through and understand them
thoroughly before you perform any of them!
( ) Switch SW1 to the ON position.
( ) Observe that all LEDs except PTT glow.
( ) After a period of about 2 seconds, the CON and STA LEDs
should extinguish (CR18 and CR19).
( ) Switch SW1 to the OFF position.
Your TNC 2 has just exercised the power-on routines. The "CON"
and "STA" LEDs turning off after first being on indicates that
all the digital circuitry is probably working. If this test was
not successful, please refer to the Troubleshooting chapter in
your TNC 2 System Manual for helpful information.
The next thing to do is verify that your TNC 2 is able to
communicate with your terminal, or computer running a terminal
program. Please refer to the chapter on Computer Interfacing in
your TNC 2 System Manual for details on fabricating an RS-232C
serial cable. Once your cable is made, please return to this
section and continue with the following steps.
( ) RS-232C serial cable properly made.
Now set your terminal to 300, 1200, 2400, 4800 or 9600 baud
(slower is better). Set the word length to 7 and parity to even.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
If the number of stop bits is settable, select 1.
( ) Terminal set to one of the above baud rates with proper
word length and parity.
( ) Now, connect your terminal (or computer) to your RS-232C
cable.
( ) Connect the other end of the RS-232C cable to your TNC
2.
( ) Apply power to your terminal (or computer).
( ) If you are using a computer, load and run your terminal
program.
( ) Set switches 1 through 5 of SW2 to correspond to your
terminal (or computer) baud rate as shown below:
Baud Rate SW2 Setting
1 2 3 4 5
300 ON OFF OFF OFF OFF
1200 OFF ON OFF OFF OFF
2400 OFF OFF ON OFF OFF
4800 OFF OFF OFF ON OFF
9600 OFF OFF OFF OFF ON
( ) In addition, set SW2 switch 7 on, and SW2 switches
6 and 8 off.
( ) Switch SW1 ON.
( ) Observe that all LEDs except PTT (CR21) glow.
( ) After a period of about 2 seconds, the STA and CON LEDs
(CR18 and CR19) should extinguish.
( ) After the two LEDs turn off, the following message
should appear on your terminal (or computer) display:
Tucson Amateur Packet Radio TNC 2
AX.25 Level 2 Version 2.0
Release nn
Checksum $xx
cmd:
(see software release notes for values of nn and
xx)
( ) A message stating "bbRAM loaded with defaults" may
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
also appear. Do not be alarmed by this message!
( ) Now enter a <carriage return> (may be marked RETURN,
ENTER, NEWLINE, etc. on your terminal or computer).
The display should now look like that below:
Tucson Amateur Packet Radio TNC 2
AX.25 Level 2 Version 2.0
Release nn
Checksum $xx
cmd:
cmd:
Note that the second "cmd:" line appears after you enter the
carriage return.
( ) Switch SW1 OFF.
Congratulations! Your TNC 2's digital circuitry and computer
interface circuitry has now been verified. If you didn't get the
expected results, recheck the Computer Interfacing chapter in the
TNC 2 System Manual and consult the troubleshooting section.
After you have the problem (if any) resolved, the following steps
will take you through verification of the digital portion of your
TNC 2 radio interface, then the completion, calibration and
verification of the modem section!
Digital Loopback Testing
You will now conduct a fairly thorough test of the digital
portion of your TNC 2 radio interface system. Known as "digital
loopback," this procedure will feed your packet transmit data
signal at digital levels to your packet receiving circuitry.
Once these tests are successfully completed, you will be able to
proceed with the final modem construction and testing with
confidence that the digital portion of your TNC 2 is performing
properly. This test facility may also prove useful for future
troubleshooting of TNC 2.
In some of the following steps you will install push-on jumpers.
They are installed by simply pressing them down over the
indicated pins. DO NOT solder them in place!
( ) Install a push-on jumper at JMP10. The jumper should
bridge both pins at JMP10.
( ) Place your terminal or computer in proper operating mode
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
as outlined in the previous test.
( ) Ensure that the RS-232C cable is properly attached
between your terminal or computer and TNC 2.
( ) Switch SW1 to the ON position.
( ) After the signon message and the cmd: prompt, enter the
following:
MY W1QRM
followed by a carriage return (abbreviated
<cr> in all following steps).
( ) TNC 2 should respond with:
MYCALL was NOCALL
cmd:
( ) Now enter:
MY<cr>
( ) TNC 2 should respond with:
MYCALL W1QRM
cmd:
( ) Verify that SW2 switch 7 in the ON position, and ensure
that SW2 switches 6 and 8 are in the OFF position.
( ) Now enter the following command to your TNC 2:
FULL ON<cr>
( ) TNC 2 should respond with:
FULLDUP was OFF
cmd:
( ) Enter:
C W1QRM<cr>
( ) You should observe the PTT LED (CR21) blink on then off.
The CON LED (CR19) will then come on shortly after you enter the
<cr> and the message:
cmd:*** CONNECTED to W1QRM
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
with NO cmd: prompt on the next line.
( ) Now enter:
hello self<cr>
( ) The PTT and STA LEDs should briefly come on, the PTT LED
blink off then on, then both LEDs go off, after which the display
should look like:
hello self
hello self
( ) Now enter a Control-C character. This is usually done
by depressing the "CTRL" key on your terminal, then pressing and
releasing the letter "C" key, then releasing the "CTRL" key. If
your terminal or computer doesn't work this way, consult your
terminal or computer manual for instructions on entering control
characters.
( ) Your TNC 2 should respond with the cmd: prompt.
( ) Now enter:
D<cr>
( ) The PTT LED will blink, then the CON LED will turn
off and your TNC 2 should respond with:
cmd:*** DISCONNECTED
followed by NO cmd: prompt.
If you are successful to this point, you have entered a call sign
in your TNC 2, instructed the TNC to ignore the DCD LED (CR20),
then established a "connection" with yourself. You had a brief
packet QSO, then ended the QSO!
The next test will verify the operation of the DCD circuitry, at
least from the digital point of view.
( ) Enter:
FULL OFF<cr>
( ) TNC 2 should respond with:
FULLDUP was ON
cmd:
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) Now enter:
C W1QRM<cr>
( ) The cmd: prompt should appear. After ten or twenty
seconds, enter:
D<cr>
( ) Your TNC 2 should respond with:
*** retry count exceeded
*** DISCONNECTED
cmd:
( ) Switch SW1 to the OFF (out) position.
( ) Using a VERY THIN piece of cut off lead (from the 1N4148
diode) place a short at socket U20 (quadrant 3) from pin 4 to pin
6. Be very careful not to stress the socket contacts.
( ) Switch SW1 to the ON (in) position.
( ) The DCD LED (CR20) should remain OFF.
( ) After the sign-on, enter:
MY W1QRM<cr>
C W1QRM<cr>
( ) The PTT LED should blink, TNC 2 should respond
with:
cmd:*** CONNECTED TO W1QRM
and the CON LED should be illuminated.
( ) Now enter a Control-C character, then:
D<cr>
( ) The PTT LED should blink, your display should now
read:
cmd:*** DISCONNECTED
and the CON LED should extinguish.
( ) Switch SW1 to the OFF (out) position.
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) Remove the push-on jumper from JMP10.
( ) Remove the wire jumper from socket U20 pins 4 and 6.
If you experienced problems in the above steps, refer to the
troubleshooting section of your TNC 2 manual for help.
In the next section, you will complete construction of the modem
and calibrate it.
Keeping in mind the precautions regarding handling ICs, install
the following ICs (quadrant 3).
( ) U16 XR2206
( ) U20 XR2211
Now install the headers as follows, being careful to align pin 1
of the header with pin 1 of the socket:
( ) U15 14-pin header with one (1) capacitor and three (3)
resistors.
( ) U17 16-pin header with eight (8) resistors only.
( ) U19 16-pin header with three (3) capacitors and four
(4) resistors.
CALIBRATION
Effective with TNC 2 firmware version 1.1.7, new calibration
procedures have been established. These are described in the TNC
2 System Manual. The original calibrations described below
should be compared to the new instructions to determine the
differences.
In the following steps, you will calibrate your TNC 2 modem
section. Exercise care, as a poorly calibrated modem may result
in poor performance in packet operation, especially when dealing
with weak signals.
If you have access to an accurate frequency counter, you may
increase the calibration accuracy by using it as described in the
calibration procedure below.
When adjusting the trimpots, you should hear a soft "click" when
the element is adjusted to the end of its travel. Turning the
element past this point will not result in damage to the trimpot;
however, it is suggested that you do not make a practice of
turning the adjustment screw past this point!
Use a small-tipped screwdriver or special trimpot adjusting tool
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in the following steps as you adjust the four trimpots on your
TNC 2.
( ) R76 Preset 20 turns counterclockwise (CCW) or until
you hear the element "click" at full CCW rotation.
( ) Now turn the adjustment screw on R76 3-1/2 complete
turns clockwise (CW).
( ) R77 Preset 20 turns CCW or until you hear the element
"click" at full CCW rotation.
NOTE: R78 and R79 will be preset CLOCKWISE, not counterclockwise
as the previous trimpots.
( ) R78 Preset 20 turns clockwise (CW) or until you hear
the element "click" at full CW rotation.
( ) R79 Preset 20 turns clockwise (CW) or until you hear
the element "click" at full CW rotation.
( ) Verify that your computer or terminal is still attached
to your TNC 2 and the proper baud rate selected.
( ) Switch SW1 to the ON position.
( ) Three LEDs should illuminate (PWR, CON and STA), then
CON and STA should extinguish. The DCD and PTT LEDs should
remain off during the power-on cycle.
( ) After the sign-on message and cmd: prompt, enter the
following to set the 1200 Hz tone:
CALSET 438<cr>
( ) Your TNC 2 should respond with:
CALSET was nn
cmd:
where nn is a number from 0 to 65535
( ) Enter the command
CALIBRATE<cr>
( ) Push on a jumper at JMP9 pins 1 and 6 (the top two pins
of JMP9).
( ) If you are using a frequency counter, place the probe at
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the push-on jumper on JMP9.
( ) Push on a jumper at JMP4.
NOTE: The STA and CON LEDs are used as a software- controlled
frequency counter in the calibrate mode. STA means that the
frequency is too high, go lower. The CON LED means that the
frequency is too low, go higher.
( ) Verify that the CON and STA LEDs are extinguished.
( ) Press the "K" key on your computer or terminal (no
carriage return is needed for this command). Either the STA or
CON LED should illuminate along with the PTT LED.
( ) Press the space bar on your keyboard and verify that the
other LED (CON or STA) illuminates in place of the one
illuminated in the preceding step.
( ) Press the space bar again until the CON LED is
illuminated.
( ) Slowly rotate the adjustment screw on trimpot R78 in the
CCW direction until both the STA and CON LEDs illuminate. The
LEDs are a bit slow to respond, so be very careful when the STA
LED begins to flicker. You will probably note a portion of the
adjustment when both LEDs illuminate; set the adjustment screw to
the center of this band. If you go too far, only the STA LED
will be illuminated; in this case, turn the adjustment screw CW.
( ) If you are using a frequency counter, adjust R78 for a
reading of 1200 Hz.
( ) When both LEDs are steadily illuminated, press the
"Q" key (with no carriage return). Both LEDs (and PTT) should
extinguish and the cmd: prompt should appear on your display.
( ) Enter the following command to set the 2200 Hz
tone on your TNC 2:
CALSET 239<cr>
( ) TNC 2 should respond with:
CALSET was 438
cmd:
( ) Type
CALIBRATE<cr>
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( ) Now press the "K" key. Either the CON or the STA LED
should illuminate as well as PTT.
( ) Tap the space bar until the STA LED glows.
( ) Slowly rotate the adjustment screw of trimpot R77
CW, following the instructions explained above in association
with the setting of R78. Continue the adjustment until both the
STA and CON LEDs glow steadily.
( ) If you are using a frequency counter, adjust R77 until
the counter reads 2200 Hz.
( ) Remove the jumper at JMP4.
( ) Verify that the STA, CON and PTT LEDs extinguish after 5
to 40 seconds. This verifies the operation of the transmit
watchdog timer.
( ) Press the "K" key twice. At the second press, the LEDs
should again glow.
( ) While the LEDs are illuminated, and before the transmit
watchdog times out, press the "Q" key. The LEDs should
extinguish and the cmd: prompt should appear on your display.
( ) If you are using a frequency counter, remove the probe
from JMP9.
( ) Remove the jumper at JMP9 pins 1 and 6.
In the next several steps you will be calibrating the demodulator
portion of the modem. This is the most critical adjustment on
TNC 2's modem. The first procedure uses the on-board calibration
facility. If you have access to a frequency counter, it includes
instructions for using it.
( ) To calibrate the 1685 Hz demodulator tone, enter the
following command to your TNC 2:
CALSET 157<cr>
( ) Your TNC 2 should respond with:
CALSET was 239
cmd:
( ) Type
CALIBRATE<cr>
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( ) Note that the STA and CON LEDs are extinguished.
( ) Now place a jumper at JMP9 pins 2 and 5 (the center two
pins).
( ) If you are using a frequency counter, place the probe at
the push-on jumper on JMP9.
( ) The CON LED should illuminate.
( ) SLOWLY rotate the adjustment screw of R79 CCW until the
STA LED blinks.
( ) Carefully rock the adjustment of R79 until both
the CON and STA LEDs glow. This adjustment is very touchy. It
should be possible to get them to both glow for a second or so
before they begin alternately blinking.
( ) If you are using a frequency counter, adjust R79 for a
reading of 3370 Hz.
( ) If you are using a frequency counter, remove the probe
from JMP9.
( ) Remove the jumper at JMP9.
( ) Verify that the STA and CON LEDs extinguish.
( ) Type "Q" and note that the cmd: prompt appears on your
display.
( ) Install a jumper at JMP8.
If you didn't have access to a frequency counter while performing
the demodulator calibration above, but you do have access to a
triggered-sweep oscilloscope (even if the oscilloscope timebase
and/or vertical deflection system isn't well-calibrated), perform
the following 11 steps.
If you used a frequency counter to calibrate the demodulator,
skip the following 11 steps.
Be sure you have completed demodulator calibration as outlined
above before proceeding.
( ) Place a push-on jumper at JMP4.
( ) Place a push-on jumper at JMP7.
( ) Verify that a push-on jumper is installed at JMP8.
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( ) Type
CALIBRATE<cr>
on your terminal, then press "K" followed by "D".
The PTT and DCD LEDs should glow.
( ) Place the oscilloscope probe at the top end of R68
(nearest Q12).
( ) You should observe a square-wave pattern, probably with
jittery edges.
( ) Adjust the timebase so one (1) cycle of the square-wave
fills the screen-edge horizontal calibrations marks exactly.
Thus, if your oscilloscope screen is calibrated 10 division wide,
one cycle of the observed waveform should be 10 divisions wide.
( ) Now, carefully adjust R79 so the transition near the
center of the oscilloscope screen occurs exactly at the center of
the screen. Again, the trace will probably be jittery, so use
the middle of the jittery area as if it were the edge of the
waveform.
( ) Press the "Q" key on your terminal. The PTT and DCD
LEDs should extinguish.
( ) Remove the jumper at JMP4.
( ) Remove the jumper at JMP7.
If you have access to a calibrated oscilloscope or a meter that
accurately reads low level audio, perform the following 7 steps.
( ) Enter the CALIBRATE command.
( ) Place a jumper at JMP4.
( ) Press the "K" key. The PTT LED should glow.
( ) Place the instrument probe at the right end of R56
(5.6k). This resistor is located in quadrant 3 just below U15.
( ) Adjust R76 for a level of about 300 mV peak- to-peak
(100 mV RMS) at this point.
( ) Remove the jumper from JMP4.
( ) Switch SW1 to the OFF position.
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Congratulations! Your TNC 2 modem is calibrated.
The next steps will guide you through a test known as "analog
loopback" which exercises your modem as if you were sending and
receiving signals on-the-air. In addition to modem testing, this
is a useful technique for operating your TNC 2 and familiarizing
yourself with its commands and features without actually placing
a signal on the air.
( ) Verify that a push-on jumper is on JMP8.
( ) Install a push-on jumper at JMP7.
( ) Switch SW1 to the ON position.
( ) Three LEDs should illuminate (PWR, CON and STA), then
CON and STA should extinguish. The DCD and PTT LEDs should
remain off.
( ) After the sign-on message and cmd: prompt, enter the
following:
MY W1QRM<cr>
( ) TNC 2 should respond with:
MYCALL was NOCALL
cmd:
( ) Verify that SW2 switch 7 is in the ON position, and
ensure that SW2 switches 6 and 8 are in the OFF position.
( ) Enter:
C W1QRM<cr>
( ) You should observe the PTT and DCD LEDs blink on then
off, followed by the CON LED illuminating shortly after you enter
the <cr>. Next, the PTT and DCD LEDs should again blink on then
off, then the message:
cmd:*** CONNECTED to W1QRM
(with NO cmd: prompt on the next line) should appear.
( ) Now enter:
hello self<cr>
( ) The PTT, DCD and STA LEDs should briefly come on, then
the PTT and DCD LEDs will turn off, after which the display
should look like:
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
hello self
hello self
( ) Next, the PTT and DCD LEDs should again blink, then the
STA LED should extinguish.
( ) Now enter a Control-C character, then:
D<cr>
( ) TNC 2 should respond with:
cmd:*** DISCONNECTED
followed by NO cmd: prompt.
( ) The PTT and DCD LEDs should blink on, then the PTT, DCD
and CON LEDs should extinguish. This action occurs very rapidly
and may be hard to see.
( ) Switch SW1 to the OFF position.
( ) Remove the push-on jumper from JMP7.
You have now verified the correct operation of the modem section.
The next section deals with installing and checking out the
battery-backed memory portion of TNC 2.
( ) Install a push-on jumper at JMP5.
( ) Apply power to TNC 2 and switch it on.
( ) Measure the voltage at the battery (BATT1) terminals of
your TNC 2 PC board.
Measured value:______________________________
( ) The measured value should be well under 0.2 volts dc.
If it is more, diode CR16 is probably installed backwards.
NOTE: If you do not have a microammeter for the following step,
use a high-impedance (10 Megohms or more) voltmeter and measure
the voltage drop across a 100 k ohm resistor used as a shunt.
The conversion factor is 10 uA/volt.
( ) Using a microammeter, measure the current through the
battery mounting holes on your TNC 2.
Measured value:______________________________
( ) The value measured should be less than 1 microampere
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(less than 0.1 volt if using the voltmeter and shunt method).
( ) Turn TNC 2 off and remove power.
( ) Remove the jumper at JMP5.
NOTE: The Lithium battery used at BATT1 must be handled with
extreme care. NEVER ALLOW A SHORT CIRCUIT ACROSS THE BATTERY
TERMINALS OR THE BATTERY COULD EXPLODE AND CAUSE SERIOUS INJURY!
WARNING: Once the Lithium battery is installed, NEVER allow your
TNC to rest on a conductive surface or you could short the
Lithium battery with the attendant dangers!
( ) I understand the danger of the Lithium battery.
( ) Remove the Lithium battery from its envelope.
( ) Note that there are two terminals on one side of the
battery and one terminal on the other side. At the side with
only one terminal there is a red-colored ring. This red-banded
end is the NEGATIVE terminal of the battery.
( ) Carefully install the battery on your TNC 2 PC board,
then solder it in place. If you have to straighten the pins on
BATT1, be careful to not short the battery terminals.
( ) Install a push-on jumper at JMP5.
( ) Using a high-impedance (at least 20k ohms/ volt)
voltmeter, measure the voltage across U25 pin 28 to ground.
Measured value:______________________________
( ) The voltage should be greater than 2.5 volts.
( ) Using a voltmeter, measure the voltage across
resistor R33 (the 1k resistor just below the battery and to the
right of Q6).
Measured value:______________________________
( ) The voltage should be under 5 millivolts.
( ) Now apply power and switch TNC 2 on.
( ) Measure the voltage across R33 again.
Measured value:______________________________
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
( ) The voltage should be under 5 millivolts.
( ) At the cmd: prompt, enter
MY W1QRM<cr>
( ) Turn off power via SW1.
( ) After a few moments, reapply power.
( ) At the cmd: prompt, enter
MY<cr>
( ) TNC 2 should respond with
MYCALL W1QRM
( ) Remove power from the TNC.
You have just completed the battery-backed memory tests. TNC 2
is now fully assembled (except for the cabinet). In the future,
you will only have to enter your call sign one time. TNC 2 will
remember it for you until you decide to change it. Likewise, all
other values that you set by non- immediate commands will be
retained until you change them.
Now it is time to connect a radio to the TNC.
Please read through the chapter on Radio Interfacing in the TNC 2
System Manual before proceeding.
( ) Radio Interfacing chapter read.
The TNC 2 radio port is designed to work with almost all common
(and many not so common) transceivers or transmitter- receivers.
The instructions below assume you are using the "Method One"
interface described in Radio Interfacing. This is a good way to
get on the air quickly, but is not recommended as a permanent
means of connecting a radio to TNC 2.
In constructing the radio interface cable, you will need to
obtain a mating connector(s) for your radio's microphone and
headphone or external speaker jack(s). We recommend you keep the
length of the radio interface cable to under about four feet (1.2
m). Use shielded wire for all audio connections.
( ) Locate the 5-pin male DIN connector pieces.
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( ) Prepare a length of shielded wire. This means to
separate the braided shield from the insulated center conductor,
then strip about 1/4" of insulation from the center conductor.
( ) Solder the center conductor to the audio output terminal
of your radio headphone/ speaker connector.
( ) Solder the shield to the audio common (or negative power
common, NOT audio common if audio common is at a positive
potential with respect to your radio's power "ground").
( ) Slide the backshell of your headphone/speaker connector
over the shielded wire and fasten to the connector.
( ) Pass the shielded wire through the insulating boot and
metal ferrule of the DIN connector and carefully solder the
center conductor to a pin for the DIN connector
( ) Insert this connector pin at pin 4 of the DIN connector.
( ) Prepare another length of shielded wire.
( ) Solder the center conductor to the microphone audio
input contact of your radio microphone connector.
( ) Solder the shield to the microphone audio common (this
common MUST be at the same dc potential as the headphone/speaker
audio common as well as dc power common).
( ) Slide the backshell of your microphone connector over
the shielded wire.
( ) Pass the shielded wire through the insulating boot and
metal ferrule of the DIN connector and carefully solder the
center conductor to a DIN connector pin.
( ) Insert this pin at pin 1 of the DIN connector.
( ) Prepare a length of unshielded wire the same length as
the microphone audio wire just completed.
( ) Solder one end of this wire to the PTT (transmitter key)
contact of your radio microphone connector.
( ) Pass this wire through the microphone connector
backshell and secure the backshell to the microphone connector.
( ) Pass the other end of this wire through the insulating
boot and metal ferrule of the DIN connector and solder it to a
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Tucson Amateur Packet Radio TNC 2 Assembly Manual
DIN connector pin.
( ) Insert this pin at DIN connector pin 3.
( ) Solder both shields to a DIN connector pin.
( ) Insert this pin at DIN connector pin 2.
( ) Inspect the DIN connector for any stray wires or other
potential causes of shorts within the connector.
( ) Place the two shield halves around the DIN connector
plug, then slide the metal ferrule over the shield halves.
( ) Slide the insulating boot over the DIN connector to
secure the connector assembly.
( ) With your radio and TNC 2 switched off, attach the
microphone and headphone/speaker connectors to your radio.
( ) Insert the DIN plug in the DIN receptacle on your TNC 2.
Now, refer to the Radio Interfacing chapter in the TNC 2 System
Manual and verify that the DCD LED flickers with audio input.
( ) Audio causes DCD LED to flicker.
Congratulations! You are now finished with the assembly of your
TNC 2! Refer to the Basic Operation chapter of the TNC 2 System
Manual for guidance through the procedures of proper packet
operation. And thank you for joining us in...
The Packet Radio Revolution!
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