Modifying Kenwood TK-760(H)G/762(H)G/860(H)G/862(H)G/863G for Packet Service

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The Kenwood TK-760(H)G/762(H)G/860(H)G/862(H)G/863G are relatively low cost commercial radios that can be reprogrammed to work in the 2m and 70cm bands and depending on band and model are rated for 25-50w output. With a steady hand and fine tipped soldering iron, they can be modified for 1200-9600 baud service, VARA FM/FM Wide, including optional COR/COS signaling for hardware carrier detect or use in other services like Allstarlink, Echolink, SVXLink, Repeater controllers/remote base, etc. This guide wires them to the Kantronics DB-9 standard and is compatible with the 4 Port packet controller and NinoTNC, details to support adaptation to other interfaces/TNCs/controllers is included.

TK-760HG TK-862G TK-863.jpg


Model Table

Model Band Channel Capacity Output Power Subband Splits
TK-760G VHF High (2m) 128 25W 1 = 148-174 MHz, 2 = 136-162 MHz
TK-760HG VHF High (2m) 128 50W 1 = 148-174 MHz, 2 = 136-162 MHz
TK-762G VHF High (2m) 8 25W 1 = 148-174 MHz, 2 = 136-162 MHz
TK-762HG VHF High (2m) 8 50W 1 = 148-174 MHz, 2 = 136-162 MHz
TK-860G UHF (70cm) 128 25W 1 = 450-490 MHz, 2 = 485-512 MHz, 3 = 400-430 MHz
TK-860HG UHF (70cm) 128 40W 1 = 450-490 MHz, 2 = 485-512 MHz, 3 = 400-430 MHz
TK-862G UHF (70cm) 8 25W 1 = 450-490 MHz, 2 = 485-512 MHz, 3 = 400-430 MHz
TK-862HG UHF (70cm) 8 40W 1 = 450-490 MHz, 2 = 485-512 MHz, 3 = 400-430 MHz
TK-863G UHF (70cm) 600 25W 1 = 450-490 MHz

A note on Bandsplits

The band splits are indicated differently between some documentation and what is actually printed on the radio. The labels on the radio seem to be numeric while the documentation references the letter K. Cross referencing the two:

K = 1
K2 = 2
K3 = 3

For VHF, the K(1) is the most common split, but both the K(1) and K2 splits cover all of 2m (144-148 MHz) without issue. For UHF, the K(1) split is also the most common split (450-490 MHz) and can usually cover at least 439-450 MHz, some of them will go down as low as 433 MHz with a simple VCO adjustment. The less common K2 split (485-512 MHz) is too far away from the 70cm band to be used and should be avoided except for part donors. The least common K3 split (400-430 MHz) can probably cover the lower portions of the 70cm band, possibly up to 440 or higher. We have not been able to obtain any of these to test, though they be may more available in proximity to Line A along the northern border of the USA and up in Canada where it is a commercial band. If you do end up with a K3 split and want a K split, please contact us to arrange a trade, we will cover shipping in both directions.


Required parts

1) Around 12" of 5 or more conductor ribbon cable, multicolor suggested
2) 34" of Devicenet 2 pair 22 gauge cable
3) 2n2222 transistor or equivalent (Optional for COR logic inverter)
4) 10K resistor (Optional for COR logic inverter)
5) 50K resistor (Optional for COR logic inverter)
6) 1-2x 3 pin 2.54mm header, commonly available for Raspberry Pi and Arduino projects (Optional 1 for COR logic signaling enable/disable and/or changing TX audio between mic and modulator input)
7) 1-2x 2.54mm jumper (Optional for connections on item 6)
8) 1/8" heatshrink tubing
9) 1/4" heatshrink tubing
10) DB9 male, solder cup type suggested
11) DB9 hood, metal plated suggested
12) Electrical tape
13) Fine tipped soldering iron and solder
14) #1 or #2 Phillips screwdriver
15) Edge wire cutters
16) Box cutter or similar knife
17) Wire stripper for 22awg wire (optional)
18) Multimeter for testing (optional)


Modification Process

Prior to beginning any modification, it is best to test the radio for proper functionality. If the radio was purchased used, there is a fair chance it is programmed to commercial frequencies. Reprogramming into the amateur bands is possible for the TK-760(H)G/762(H)G/860(H)G/862(H)G using the KPG-56D software which is available in both DOS and Windows. The TK-863G requires KPG-76D and is available only for Windows. In general, the VHF high band versions will work well into the 2m band with little or no adjustments needed to the VCO or receiver. The UHF versions (K split, 450-490 MHz) will often work without modification in the upper 9-10 MHz (441-450 MHz) and sometimes lower. Many of the UHF versions can go lower into the 70cm band by adjusting the VCO circuits. Some may go down as low as 433 MHz or possibly lower. It should be possible to add small amounts of parallel capacitance across the trimmer capacitors in the VCO section to pull it's range lower in frequency. This will likely be explored in the future.

1) Open the top cover by removing the two rear screws near the heatsink

TK-n6ng top removal.jpg TK-n6ng top removed.jpg

2) With the top cover removed, use a pair of pliars to gently pull out the speaker from the main board, setting the speaker aside for now.

TK-n6ng speaker removal1.jpg TK-n6ng speaker removal2.jpg TK-n6ng speaker removal3.jpg

3) Flip the radio over and remove the two rear screws near the heatsink

TK-n6ng bottom removal.jpg TK-n6ng bottom removed.jpg

4) Gently lift up on the tabs on the faceplate and slide forward

TK-n6ng bottom face removal.jpg

5) Flip the radio over and lift up on the tabs on the faceplate and slide forward

TK-n6ng top face removal.jpg TK-n6ng top face removed1.jpg TK-n6ng top face removed2.jpg

6) Pull the faceplate forward, there is a rubber membrane for the keys which may separate from the faceplate or remain in the faceplate. Separated membrane shown.

TK-n6ng face removed with membrane.jpg

7) Remove the two faces which hold on the faceplate circuit board

TK-n6ng face removal1.jpg TK-n6ng face removal2.jpg

8) Gently pull the faceplate circuit board forward, it may be somewhat "stuck" to the chassis, be careful not to pull to hard which could damage the ribbon to the main board.

TK-n6ng face circuitboard forward1.jpg TK-n6ng face circuitboard forward2.jpg

9) Lay the faceplate circuit board down, exposing the solder side

TK-n6ng face circuitboard down.jpg

10) Carefully pull up the brown tabs on either side of where the ribbon cable locks into the faceplate circuit board

TK-n6ng face ribbon unlock.jpg

11) Pull the ribbon cable away from the faceplate circuit board.

TK-n6ng face ribbon removed.jpg

12) Flip the faceplate circuit board to where the ribbon cable attachment faces down

TK-n6ng faceplate circuit.jpg

13) Our area of interest is on the bottom right side of the faceplate circuit board

TK-n6ng faceplate bottom right corner.jpg

14) Cut about 5 inches of 5 conductor ribbon cable. If you want to have support for COR signaling strip back about 1/8" of all 5 wires, twist and tin. If you do not want to add COR support (not required for packet) strip back about 1/8" of 4 wires, leaving one unstripped or it can be removed completely. In this guide we will show COR support. Separate 2 of the 5 wires several inches, the separation of the remaining 3 can be left short. In this build

Green = PTT
Yellow = Mic Audio
Orange = Ground
Red = RX Audio (Discriminator)
Brown = COR (Active high)

TK-n6ng ribbon stripped tinned separated.jpg

15) Solder the PTT wire to the second from left pin behind the microphone jack

TK-n6ng PTT soldered.jpg

16) Solder the Mic Audio wire to the third from left pin, next to the PTT wire

TK-n6ng Mic audio soldered.jpg

17) Repositioning the wire, solder the ground wire to the grounding pad below the microphone jack to the left

TK-n6ng Ground soldered.jpg

18) Carefully apply solder to one of the two surface mount resistors that carry Discriminator audio

TK-n6ng discriminator resistor tin.jpg

19) Add a bit more solder to the tip of the RX audio wire. Try to make it look a bit like a rain drop.

TK-n6ng RXAudio extra solder.jpg

20) Carefully hold the tinned RX audio wire over the surface mount resistor and apply heat, the goal is to melt the extra solder to flow over the resistor

TK-n6ng RXAudio soldered.jpg

21) Using electrical tape or some other method, apply strain relief on the RX audio wire to try and keep any mechanical stress off the solder joint.

TK-n6ng RXAudio wire strain relief.jpg

22) Feed the ribbon cable through the small hold in the top/center of the chassis to the main body of the radio. The COR wire is still "floating" at this point.

TK-n6ng ribbon to body.jpg

22) Pull away the COR wire, this will be fed to the opposite corner of the face plate to be passed next to the ribbon cable to the under side of the radio. This will split about where the ribbon cable passes through to the main body of the radio.

TK-n6ng COR wire detached.jpg

23) Feed the COR wire through the small opening in the chassis that passes the thin ribbon cable between the face plate and main board

TK-n6ng COR wire feedthrough1.jpg TK-n6ng COR wire feedthrough2.jpg

24) Side the face plate circuit board back towards the main chassis of the radio, lining up the ribbon cable with the attachment point.

TK-n6ng faceplate ribbon lineup.jpg

25) Slide the ribbon cable back into position. Be sure to press inward to try and get the ribbon cable fully seated.

TK-n6ng faceplate ribbon inserted.jpg

26) Gently press down on the brown tabs on either side to lock the ribbon cable in place.

TK-n6ng faceplate ribbon locked.jpg

27) Press the faceplate circuit board back against the main chassis. Be careful not to pinch any of the wires we soldered in the process and that the COR wire remains visible in the under side of the radio. Reattach the first screw holding the faceplate circuit board.

TK-n6ng faceplate circuit board reattach1.jpg

28) Flip the radio over and attach the second screw holding the faceplate circuit board.

TK-n6ng faceplate circuit board reattach2.jpg

29) If COR signaling is desired, flip the radio over putting the side with the COR wire fed to the front. This is where our COR circuit will be attached. If COR signaling is not desired, skip to step 71

TK-n6ng bottom COR location.jpg

30) Take a 2n2222 or equivalent transistor, 10k resistor and 50k resistor. These will allow us to invert the COR logic, which is natively active low to be active high. We want to attach the 10k resistor to the emitter and 50k resistor to the base.

TK-n6ng COR inverter1.jpg

31) Trim the leads on the 2n2222 to about 1/4".

TK-n6ng COR 2n2222 lead trim.jpg

32) Apply solder to all 3 leads on the 2n2222

TK-n6ng COR 2n2222 tinned.jpg

33) Trim one of the leads on the 50k resistor to about 1/4" and tin the lead.

TK-n6ng COR 50k trim.jpg TK-n6ng COR 50k tin.jpg

34) Solder the 50k resistor to the base (center wire) of the 2n2222.

TK-n6ng COR 50k to 2n2222.jpg

35) Trim one of the leads on the 10k resistor about 1/4" and tin the lead.

TK-n6ng COR 10k trim.jpg TK-n6ng COR 10k tin.jpg

36) Solder the 10k resistor to the emitter (left of base pictured) of the 2n2222.

TK-n6ng COR 10k to 2n2222.jpg

37) Take about 2" of single wire from the ribbon cable to be use for COR logic inverter output, strip back about 1/4" but do not tin. In this build we will use an orange wire.

TK-n6ng COR output wire strip.jpg

38) Take the stripped end of the COR logic inverter output and wrap it around the soldered connection between the 10k resistor and 2n2222 emitter.

TK-n6ng COR output wire wrapped.jpg

39) Solder the COR logic inverter output wire around the 2n2222 and 10k resistor junction as shown.

TK-n6ng COR output wire soldered.jpg

40) Trim both the 10k and 50k resistor legs about 1/4" on the opposing lead that is soldered to the 2n2222.

TK-n6ng COR resistors trimmed.jpg

41) Take about 2" of single wire from the ribbon cable to be used for the 5VDC feed, strip back about 1/4" and tin. In this build we will use a purple wire.

TK-n6ng-COR 5v wire strip tin.jpg

42) Solder the COR logic inverter 5v input to the 10k resistor.

TK-n6n-COR 5v to 10k resistor.jpg

43) Take about 3" of single wire from the ribbon cable to be used for the COR signal feed, strip back about 1/4" and tin. In this build we will use a red wire.

TK-n6ng COR signal strip tin.jpg

44) Solder the COR signal input to the 50k resistor.

TK-n6ng COR signal to 50k resistor.jpg

45) Take about 4" of single wire from the ribbon cable to be use for the COR inverter circuit ground, strip back about 1/4" and tin. In this build we will use a grey wire.

TK-n6ng COR ground strip tin.jpg

46) Solder the COR ground to the collector of the 2n2222 (only lead without a resistor attached)

TK-n6ng COR ground to 2n2222.jpg

47) Cut two 3/4" sections and one 3/8" section of 1/8" heatshrink tubing

TK-n6ng COR circuit heatshrink1.jpg

48) Slide the two 3/4" sections over both leads that have resistors and the 3/8" section over the junction of the 2n2222 collector and ground wire.

TK-n6ng COR circuit heatshrink2.jpg

49) Apply heat to the circuit, making sure the heatshrink tubing stays as close to the 2n2222 as possible.

TK-n6ng COR circuit heatshrink3.jpg

50) Cut one 3/4" section of 1/4" heatshrink tubing and slide over the circuit, leaving the heatshrink just past the top of the 2n2222

TK-n6ng COR circuit heatshrink4.jpg TK-n6ng COR circuit heatshrink5.jpg

51) Apply heat to the circuit, securely covering the 2n2222

TK-n6ng COR circuit heatshrink6.jpg

52) Returning to the radio, apply a small amount of solder to the left most/output leg of IC10NJM78L05UA 5V regulator's output near the 5C label, in the center of the main board next to the ribbon cable.

TK-n6ng COR 5v schematic.jpg TK-n6ng COR 5v source tin1.jpg TK-n6ng COR 5v source tin2.jpg

53) Apply a small amount of solder to the left anode of D15/DAN235K near the outside of the radio.

TK-n6ng COR signal schematic.jpg TK-n6ng COR trigger source tin1.jpg TK-n6ng COR trigger source tin2.jpg

54) Strip and tin about 1/8" from the ends of the 5v, COR signal and ground wires. The heat may melt off some of the insulation and additional trimming may be required to get the desired short lengths.

TK-n6ng COR leads trim tin.jpg

55) Solder the 5v wire to IC10/NJM78L05UA 5V regulator's output pin closest to the center of the radio.

TK-n6ng COR 5v connected.jpg

56) Solder the COR signal wire to the outer input of D15/DAN235K near the output of the radio.

TK-n6ng COR signal connected.jpg

57) Take the COR logic inverter output wire and run it towards the front of the radio, it should overlap with the COR wire we fed through earlier

TK-n6ng COR logic output forward.jpg

58) Strip about 1/4" of insulation and tin the output wire.

TK-n6ng COR logic output strip tin.jpg

59) Cut about 3/8" of 1/8" heatshrink tubing and slide over the COR logic inverter output wire.

TK-n6ng COR logout output heatshrink1.jpg

60) If you want the COR logic to be permanently connected, solder the COR logic output wire to the COR wire that feeds to the front of the radio. If you do not, skip to step 62.

TK-n6ng COR logout output soldered.jpg

61) Slide the 3/8" of 1/8" heatshrink tubing over the COR logic output wire junction and heat up.

TK-n6n COR logic output heatshrink2.jpg

62) If you want to be able to enable or disable COR signaling via hardware jumper, take a single row of 2.54mm header pins and tin 3 consecutive pins. This is needed if you want to use this radio with a CM108/RA/URI type interface that supports COR signaling on Windows. With the COR connected all the time to that type interface, the COR signal will mute the speaker output whenever a signal is present and have to manually be reenabled.

TK-n6n COR logic header prep.jpg TK-n6n COR logic header tin.jpg

63) Trim off the prepared 3 pins from the header pins

TK-n6ng COR logic header pin trim.jpg

64) Attach the COR logic output wire to one of the outside pins of the 3 pin header.

TK-n6ng COR logic header pin output.jpg

65) Slide about 3/8" of 1/8" heatshrink over the COR wire leading to the front of the radio to the center pin of the 3 pin header.

TK-n6ng COR logic header pin front.jpg

66) Slide the heatshrink tubing up the COR logic output and front wires, covering both the center and unused pins with the output wire heatshrink tube.

TK-n6ng COR logic header heatshrink1.jpg

67) Take a 2.54mm jumper (this can be scavenged from old computer harddrives and other devices) and place it over the pins connected to the COR logic output and front wires and apply heat.

TK-n6ng COR logic header heatshrink2.jpg

In this position, COR output is connected and the radio will send a 5V signal whenever a signal is present.

To disable this connection, move the jumper over to the pin which is not connected.

TK-n6ng COR logic header heatshrink3.jpg

68) Take about 1" of 1/4" heatshrink tubing and slide it over the header/jumper assembly. Do not heat this, the heatshrink should provide a friction fit over the jumper to safely insulate the jumper while allowing its position to be changed at some future time.

TK-n6ng COR logic heatshrink.jpg

69)Take the COR logic ground wire, lay it out to reach the back corner of the radio, trim to length to reach the large ground solder pad in the corner.

TK-n6ng COR logic ground trim1.jpg TK-n6ng COR logic ground trim2.jpg

70) Strip and tin about 1/4" of the ground wire, soldering it to the rear solder pad. This concludes the COR logic setup.

TK-n6ng COR logic ground connected.jpg

71) Flip the radio so it's top is facing up, separate, strip about 1/8" and tin all 5 wires. If you skipped the COR circuit, strip and tin all 4.

TK-n6ng ribbon strip tin.jpg

72) Cut about 34" of Devicenet cable to be used to bring signaling out of the radio.

TK-n6ng devicenet cut.jpg

73) Carefully cut the jacket off the devicenet cable about 5/8" from the end.

TK-n6ng devicenet jacket cut.jpg

74) Bend the Devicenet cable back and forth, this should cause the outer jacket to separate, exposing the braid.

TK-n6ng devicenet jacket bend.jpg

75) Rocking the devicenet cable back and forth and making any needed small cuts to break it free, pull the 5/8" section of outer jacket off.

TK-n6ng devicenet jacket removal1.jpg TK-n6ng devicenet jacket removal2.jpg

76) Fold back the outer braid from the Devicenet cable and trim away any of the nylon strands inside the braid.

TK-n6ng devicenet nylon trim.jpg

77) Separate the two wire pairs and bare ground lead.

TK-n6ng devicenet wires separated.jpg

78) Pull away the foil shield that is covering both wire pairs. A small cut in the foil may be needed to ease it's removal. When removed, separate all 5 wires. In this build and recommended if your devicenet colors match:

Red = TX Audio
Black = PTT
Blue = RX Audio
White = COR
Bare = Ground

TK-n6ng devicenet foil removed.jpg

79) Strip about 1/8" of all 4 and tin all 5 wires. If you omit the COR circuit, do not strip or tin the white wire.

TK-n6ng devicenet stripped tinned.jpg

80) Take five 3/8" long sections of 1/8 heatshrink tubing. and one 1" long section of 1/4" heatshrink tubing.

TK-n6ng devicenet heatshrink cut1.jpg TK-n6ng devicenet heatshrink cut2.jpg

81) Slide the 1" long 1/4" heatshrink tubing over the ribbon cable that runs to the front of the radio.

TK-n6ng ribbon heatshrink.jpg

82) To provide optional input to the modulator (needed for 4800 and 9600 baud packet as well as VARA FM WIDE), locate CN4 on the side of the radio where the DC power cable exits. This is an 8 pin header and we are interested in pin 4. This is the only pin that has the surface mount capacitor near by.

TK-n6ng CN4 jack.jpg

83) Carefully take a soldering iron and solder and create solder bridge between the pin on the connector and surface mount resistor. These two components are already shorted, this bridge gives a larger area to solder the wire to be brought out of the radio.

TK-n6ng CN4 jack solder bridge.jpg

84) Take about 5" of single wire from the ribbon cable, strip about 1/8" and tin the end to be used for the modulator input tap. In this build this wire is gray.

TK-n6ng modulator wire strip tin.jpg

85) Carefully solder the modulator input wire to the solder bridge created in step 83.

TK-n6ng modulator wire connected.jpg

86) Leave plenty of extra wire to try and minimize mechanical stress on the connection, run it around the outside wall of the chassis and trim about 1/2" past the internal cylinder on the inside of the chassis.

TK-n6ng modulator wire run.jpg

87) Strip and tin about 1/8" of the modulator wire.

TK-n6ng modulator wire stripped tinned.jpg

88) Slide one of the 3/8" of 1/4" heatshrink tubes over the white wire and solder the white devicenet wire to the COR circuit wire(brown in this build). If you omit the COR circuit, set aside the heatshrink and leave the devicenet white wire for now.

TK-n6ng devicenet ribbon COR connected.jpg

89) Slide one of the 3/8" of 1/4" heatshrink tubes over the blue wire and solder the blue devicenet wire to the RX audio wire (red in this build).

TK-n6ng devicenet ribbon RX audio connected.jpg

90) Slide one of the 3/8" of 1/4" heatshrink tubes over the bare wire and solder the bare devicenet wire to the ground wire (orange in this build).

TK-n6ng devicenet ribbon ground connected.jpg

91) Slide one of the 3/8" of 1/4" heatshink tubes over the black wire and solder the black devicenet wire to the PTT wire (green in this build).

TK-n6ng devicenet ribbon PTT connected.jpg

92) If you opted to make a modulator input, take a 2.54mm header pin and tin 3 consecutive pins.

TK-n6ng TX input 3pin header tin.jpg

93) Cut the 2.54mm 3 pin header which has it's pins tinned.

TK-n6ng TX input 3pin header cut.jpg

94) Cut three 3/8" sections of 1/4" heatshrink tubing.

TK-n6ng TX input heatshrink cut.jpg

95) Take about 3" of single wire from the ribbon cable, strip about 1/8" and tin the end to be used for the TX input switch (microphone or modulator). In this build this wire is gray.

TK-n6ng TX input common.jpg

96) Slide one of the 3/8" of 1/4" heatshrink tubes over the input wire and solder it to the center pin of the 3 pin header.

TK-n6ng TX input common connected.jpg

97) Separate about 1" of the mic audio line (yellow) that runs to the front of the radio.

TK-n6ng mic audio separated.jpg

98) Feed the microphone audio line back through the heatshrink tubing.

TK-n6ng mic audio through heatshrink.jpg

99) Pull the 1/4" heatshrink tubing towards the solder junctions, exposing the mic audio line.

TK-n6ng mic audio pulled heatshrink forward.jpg

100) Slide one of the 3/8" of 1/4" heatshrink tubes over the modulator input wire.

TK-n6ng modulator wire with heatshrink.jpg

101) Solder the modulator input wire to one of the outside pins of the 3 pin header.

TK-n6ng modulator wire connected.jpg

102) Slide one of the 3/8" of 1/4" heatshrink tubes over the microphone input wire.

TK-n6ng mic input with heatshrink.jpg

103) Solder the microphone input wire to the remaining outside pin on the 3 pin header.

TK-n6ng mic wire connected.jpg

104) Slide all 3 pieces of 3/8" heatshrink up against the 3 pin header.

TK-n6ng audio input header heatshrink1.jpg

105) Apply heat, carefully trying to shield the 1/4" heatshrink still over the remainder of the ribbon cable.

TK-n6ng audio input header heatshrink2.jpg

106) Attach a computer type jumper to the header.

In this position, input audio is sent to the microphone input. This is suitable for 1200 and 2400 baud, VARA FM as well as most NBEMS/fldigi type modes.

TK-n6ng audio input microphone.jpg

In this position, input audio is sent to the modulator input. This is suitable for 4800 and 9600 baud and VARA FM wide.

TK-n6ng audio input modulator.jpg

107) Cut one 1" long section of 1/4" heatshrinkg tubing.

TK-n6ng audio input selector heatshrink cut.jpg

108) Slide this over the TX audio input selection jumper. Do not heat this, the heatshrink should provide a friction fit over the jumper to safely insulate the jumper while allowing its position to be changed at some future time.

TK-n6ng audio input selector heatshrink applied.jpg

109) Slide the common (center) wire from the TX audio selection jumper through the heatshrink tube which covers the ribbon cable.

TK-n6ng audio input common heatshrink1.jpg

110) Slide the 1/4" heatshrink tubing back across the ribbon cable, cut the common TX audio wire to length in order to solder to the red Devicenet wire.

TK-n6ng audio input trim.jpg

111) Trim and tin about 1/8" of the common TX audio wire, side a 3/8" length of heatshrink tube over the red Devicenet wire.

TK-n6ng audio input trim tin.jpg

112) Solder the red Devicenet wire to the common TX wire (grey in this build). If you omit the modulator input, solder red Devicenet wire to the microphone input wire (yellow).

TK-n6ng devicenet TX audio connected.jpg

113) Slide all heatshrinks over the junctions between the Devicenet and ribbon cable. If you omitted the COR circuit, place heatshrink over the end of the white Devicenet cable, allowing the heatshrink to extend past the end of the white wire.

TK-n6ng devicenet to ribbon heatshrink prep.jpg

114) Apply heat to the solder junctions, carefully try to shield heat from the 1/4" heatshrink slide down the ribbon cable.

TK-n6ng devicnet to ribbon heatshrink applied.jpg

115) Carefully slide the 1/4" heatshrink tubing up the ribbon cable and over the soldered/heatshrink bundle. This may be a tight fit, it is possible to slightly stretch the heatshrink using needle nose pliers or similar method. Ideally the outer 1/4" heatshrink sould cover all the other pieces of heatshrink.

TK-n6ng outer heatshrink slide1.jpg TK-n6ng outer heatshrink slide2.jpg

116) Apply heat to this heatshrink to keep it in place, then wrap electrical tape starting near the end of the heatshrink on the ribbon cable and covering up all braid wires on the Devicenet cable.

TK-n6ng ribbon devicenet heated taped.jpg

117) Pull the DC power cable out of the groove in the main chassis, moving it towards the middle of the radio.

TK-n6ng power cable move.jpg

118) Reinstall the internal speaker, the jack near two large capacitors

TK-n6ng internal speaker reconnected.jpg

119) Press the Devicenet cable into the DC power groove. This is going to be a tight fit.

TK-n6ng devicenet to groove.jpg

120) It may be necessary to reroute the speaker wire from in between the capacitors to around the front to allow clearance for the devicenet cable.

TK-n6ng devicenet speakerwire moved.jpg

121) Double check the TX audio input jumper, select which input you want audio to be delivered (microphone or modulator). Once selected, slide the 1/4" heatshrink tube over the jumper and tuck it behind the cylinder on the main chassis towards the front of the radio.

TK-n6ng input header insulated secured.jpg

122) Move the DC power cable back into the groove, this will not fit initially since the Devicenet cable is sharing this space.

TK-n6ng devicenet powercable grove.jpg

123) If the front rubber membrane separated during disassembly, line it back up and place it back into the faceplate.

TK-n6ng faceplate membrane1.jpg TK-n6ng faceplate membrane2.jpg

124) Carefully slide the faceplate to the front of the radio, try to keep the faceplate square to the radio chassis so it can snap on evenly.

TK-n6ng faceplate reattach1.jpg TK-n6ng faceplate reattach2.jpg

125) Slide the speaker back into position, there is a section in the chassis with two circles where the speaker is designed to rest.

TK-n6ng speaker remounted.jpg

126) Take the top cover of the radio (it has holes for the speaker output and place it on the top of the radio. It will not fit initially over the side with the power and Devicenet cable.

TK-n6ng top cover1.jpg

127) Apply slight pressure to the top cover and attach the case screw opposite of the power and devicenet cable.

TK-n6ng top cover screw1.jpg

128) Applying slight pressure on the opposite side, try to get the other screw to "bite". We don't want to fully tighten this way as it may bend the cover slightly.

TK-n6ng top cover screw2 started.jpg

129) Flip the radio over looking at the bottom, if the COR circuit was installed, double check that the jumper is in the desired position and verify the 1/4" heatshrink covers the jumper.

TK-n6ng bottom.jpg

130) Reattach the bottom cover, this cover is one solid piece of metal and has no holes for a speaker. Apply both screws and turn until tight.

TK-n6ng bottom cover reattached.jpg

131) Flipping the radio back over, examine the top of the case where the power and devicenet cable exits. This will probably not be flush.

TK-n6ng top not flush.jpg

132) Place the radio under a flat and heavy surface (workbench works well) and push upwards, this will cause the devicenet cable to push downward and the rubber grommet of the power cable to spread out. This will make the case flush with the radio and the screw head should appear raised.

TK-n6ng top pressed.jpg

133) Finish tightening the top case screw near the power and Devicenet cable.

TK-n6ng top secured.jpg

134) Check the side of the case to ensure it's made a firm seal with no major gaps between top and bottom covers.

TK-n6ng top cover check.jpg

135) Remove about 5/8" of the Devicenet cable which is outside the radio, folding the braid back, removing the foil, separating the wires and tinning all 5 wires as completed in steps 73-80. If the COR circuit was omitted, we will still strip and tin the white wire to keep it from floating in the DB9 connector.

TK-n6ng devicenet db9 prep.jpg

136) Take a DB9 solder type male connector with the 5 pin row facing up. Apply solder to pin 1.

TK-n6ng DB9 tin pin1.jpg

137) Repeat applying solder to pins 2, 3 and 5.

TK-n6ng DB9 tin pin2 3 5.jpg

138) Flip the DB9 connector and apply solder to pin 6.

TK-n6ng DB9 tin pin6.jpg

139) Moving the DB9 onto it's side, apply solder to the shell of the DB9 next to pins 1 and 6.

TK-n6ng DB9 tin DB9 shell.jpg

140) Taking the Devicenet cable, solder the white wire (COR) to DB9 pin 2.

TK-n6ng DB9 COR connected.jpg

141) Solder the black wire (PTT) to DB9 pin 3.

TK-n6ng DB9 PTT connected.jpg

142) Solder the red wire (TX Audio) to DB9 pin 1.

TK-n6ng DB9 TX audio connected.jpg

143) Solder the blue wire (RX Audio) to DB9 pin 5

144) Flip the DB9 over and solder the bare wire to pin 6

TK-n6ng DB9 ground connected.jpg

145) Take about 3/4" of single wire from the ribbon cable to be used for the DB9 shell ground, strip back about 1/8" and tin on side and strip about 1/4" on the other, but do not tin. In this build we will use a orange wire.

TK-n6ng DB9 shell ground wire.jpg

146) Take the 1/8" tinned portion of the shell ground wire and solder it to the DB9 shell.

TK-n6ng DB9 shell ground attached.jpg

147) Take the 1/4" stripped portion of the shell ground wire and wrap it around the bare wire.

TK-n6ng DB9 shell ground wrapped.jpg

148) Solder the wrapped shell ground wire to the bare wire.

TK-n6ng DB9 shell ground soldered.jpg

149) Place the Devicenet cable in a suitable DB9 hood, metal plated recommended. About 1/4" past where the hood ends, wrap with electrical tape. This will securely hold the Devicenet cable in the hood and relieve the soldered connections of any mechanical stress. Using Scotch 33+ tape, 4 or 5 turns seems to work well.

TK-n6ng devicenet DB9 hood tape1.jpg

150) Attach the DB9 hood over the DB9, the wraps of electrical tape will make this a tight fit. Slide the locking screws through the front, then add the screws and nuts to fully secure the hood.

TK-n6ng DB9 hood installed.jpg


Post modification testing

Multimeter + Second radio testing:

1) Take a continuity tester and verify a DC short between the DB9 pin number 6 and the radio chassis as well as DB9 shell
2) Measure for DC voltage across DB9 pin number 3 (PTT). If present, attach suitable antenna or dummy load to modified and short pin 3 to the DB9 shell or DB9 pin 6, this should cause the radio to transmit.
3) Measure AC voltage across DB9 pin 5. This is discriminator receive audio and will be a fairly steady AC voltage with no signal present. If AC voltage is measured and another transmitter is available, transmit a dead carrier with no audio, this should cause the AC voltage to drop significantly if not fully near 0 volts indicating the receiver has a full quieting signal.
4) If the COR circuit was added and COR enable jumper was placed, measure DC voltage across DB9 pin number 2. With no signal present, the DC voltage should be near 0. Using either the MON function on the front of the radio OR using a secondary transmitter on the frequency, open up the squelch and this pin should read about 5VDC.
5) Create a short between DB9 pin numbers 1 (TX Audio) and 5 (RX Audio). On an secondary receiver, tune to the modified radio transmit frequency. Short DB9 pin 3 to ground either on the DB9 shell or DB9 pin 6. This should cause the radio to transmit and the secondary receiver should pick up a signal with static. Momentarily break the short between DB9 pin numbers 1 and 5, this should turn the signal from full quieting and static off the discriminator.


Soundcard interface/packet controller/hardware TNC testing:

1) Attach the radio to a compatible interface. If the interface/TNC does not use the Kantronics DB9 standard, a suitable adapter will need to be made. To review, the DB9 pinout is:

DB9 Pin 1 = TX Audio
DB9 Pin 2 = COR (Active High) - if built and enabled
DB9 Pin 3 = PTT (Active Low)
DB9 Pin 5 = RX Audio
DB9 Pin 6 = Ground

2) Place the modified radio on a known packet frequency. If none is available on VHF, a good candidate for traffic is the national APRS frequency, 144.390 MHz in North America, 144.80 in Europe. Optionally turn up the volume on the radio and listen for packet bursts to come out of the speaker. When a packet burst is heard, check the interface/TNC for a successful decode.
3) Placing an auxiliary receiver on the radio transmit frequency, issue an outbound connection and listen for a packet burst on the auxiliary receiver. If no other station exists, a dummy call can be used:

C XX1XX


Please pass along any modification questions or suggestions regarding this modification process.