The FT290R Mk2 was introduced to the UK in around 1986, updating and replacing the very popular FT290R. It is a 2 metre all mode portable transceiver, but its usefulness is now limited by its lack of CTCSS, in common with many other well regarded transceivers of that era.
Having recently installed several CTCSS tone generator boards designed by Colin Tuckley G8TMV, I was asked to help to install the board in a friend’s FT290R Mk2.
The rig was supplied originally with a small 1750Hz toneburst board (FTE-2) installed in a recess behind a removable panel on the rear face of the transceiver. This was activated by pressing the ‘CALL’ button on the front panel. At the same time the PTT line was grounded putting the transmitter into ‘SEND’ and transmitting the 1750Hz access tone. The CALL button was active only for as long as it was depressed.
Yaesu did make a CTCSS board designed to be installed in the rear panel recess as an alternative to the toneburst board. This was the FTS-7. The tone was selected by altering a DIL switch on the board; i.e. the battery pack or linear amplifier, and rear panel had to be removed to gain access.
I believe that the FTS-7 was not supplied in the UK as its installation would have involved more alterations to the transceiver than simply connecting the board. The FT290R Mk2 user manual makes reference to the CTCSS board being installed in the ’A’ version. Simply replacing the FTE-2 with the FTS-7 will not work.
I had no access to any installation instructions for the FTS-7. Thanks to the work of ZS1KE and PE1HZG, enabling me to understand the 290’s switching arrangements, I was able to utilise the original connections to Power, Ground, PTT, and Tone output. Also, I was able to repurpose the front panel CALL button and use it to select the CTCSS tone.
The crucial area is highlighted on the relevant area of the circuit shown below. This is on the CPU board. For transceivers supplied for use with the toneburst board FTE-2, the ‘jumpers’ JP04 and JP05 are linked CENTRE pin to LEFT. Pressing the CALL button grounds the line connected to JP05 centre. This grounds the emitter of Q07 and grounds the PTT line via diode D03. The transmitter is now ‘on’. With jumper JP04 also in the burst position, the base of PNP transistor Q06 is also grounded thus energising the Vcc line to the FTE-2 via pin 5 of the connector (top left of circuit below). The problem here is that the tone board is only powered while the CALL button is depressed.
For installation of the FTS-7 CTCSS board, the jumpers are intended to be connected CENTRE pin to RIGHT. This now connects the CALL button as a ‘HOME’ memory channel via JP05 and power is applied to the Vcc line via Q06 which is switched on by pin 72 (R22) of the microprocessor.
My solution was to connect JP04 CENTRE to RIGHT so that the microprocessor controlled power to the G8TMV board, but I removed jumper J05 altogether connecting the CENTRE to the control line on the G8TMV board. This neatly gives front panel control of the CTCSS tone using the CALL button.
UK versions which used the FTE-2 board, never enjoyed a ’home’ channel button so that feature will not be missed.
Unfortunately the G8TMV board, while only 35mm by 35mm, is too large to fit in the rear panel recess. It was therefore installed with double sided adhesive sponge tape on the underside of the top case panel. In order to avoid damaging the original wiring loom, the connector on the redundant FTE-2 board was carefully removed and wiring was attached to the pins required to connect to the CTCSS board (see below).
The result is a very neat, invisible installation which is extremely user friendly.
Thanks to Colin Tuckley for designing and supplying this excellent CTCSS encoder.
G8TMV Board Update
Please note that Colin has since released his Rev. 5 board which is slightly smaller and also includes a ‘down’ button. This would enable the tone to be selected by scrolling up or down the list, but would require an extra switch. The new rev. 5 board can be used exactly as described here by using only the ‘up’ button.
- Remove the rear mounted battery pack or linear amplifier.
- Remove both side panels.
- Remove four cross head screws from the top and bottom panels (PH0x75 driver or similar).
- Remove top and bottom panels. Disconnect the loudspeaker from the connector on the main PCB front right.
- Carefully disconnect the Molex connectors from the control unit board, which is the vertical board mounted behind the front panel with a fuse mounted on the upper edge.
- Remove three screws mounting the control board- two on the top edge and one on the lower edge.
- Gently ease the front panel away from the main board. We are interested in access to the rear facing aspect of the CPU PCB which is in front of the control PCB. Turn the rig bottom side uppermost and tilt the front panel forwards to expose the area of the CPU PCB adjacent to the Microphone socket. (see below)
- I naively expected the ‘jumpers’ to be similar to those seen in computers these days requiring simply to be relocated with forceps. However it turns out they are very small soldered wire links. These need to be removed. They could either be cut or unsoldered. I unsoldered them by heating them with a soldering iron while lifting them with a fine sharp probe. Be careful not to overheat and damage the PCB tracks.
- Form a new jumper link from tinned copper wire or a component lead remnant and carefully solder it across the right hand pair of contacts on JP04. The link can stand a little higher off the PCB than the original to make insertion easier.
- Solder a length of thin multi-strand hook-up wire to the centre contact of JP05- about 20cm should be plenty.
- Now reverse the last few disassembly steps:
Refit the three screws holding the control board and re-engage the connectors with the main board. Once properly seated, refit the side panels and carefully reconnect all the Molex plugs which were removed previously.
- Route the wire just connected to JP05 past the control board to the topside of the rig prior to connection to the CTCSS board.
- Desolder the six way connector from the redundant tone-burst board. This is used to connect to the rig’s wiring loom without causing any permanent damage. If there is no such connector available the best thing would probably be to remove the loom end connector and connect the relevant wires to the G8TMV board direct. I soldered wires for Vcc (red,) ground (black), PTT (green) and tone-out (orange) as shown below.
- The annunciator sounder needs more current than can be supplied by the LED output of the G8TMV board. A general purpose NPN transistor is used to switch the Piezzo sounder. I used a PN2222 but any similar NPN transistor should do. Ideally choose one with adjacent base and emitter connections.
- Mount the transistor on the CTCSS board-connect the base to ‘LED’ and the emitter to ‘Gnd’. Connect another thin multi-strand wire to the collector and insulate the joint with heatshrink sleeve. Solder the other end of this wire to the negative terminal of the Piezzo sounder.
- Run a wire from the Piezzo positive terminal back to +v terminal on the CTCSS board. Solder the red supply wire to the same point.
- Connect the ground wire (black) to another Gnd terminal on the board.
- Connect the tone out wire (orange) to the o/p terminal and the PTT wire (green) to the PTT terminal.
- Connect the wire from JP05 to the terminal marked ‘But’ (Button).
- Wrap the Piezzo sounder in a layer of thin expanded polythene foam and secure with tape.
- Ensure all wires are trimmed well on the reverse side of the CTCSS board and secure to the underside of the top panel with thick double sided foam tape. I mounted the board 35mm from the side and 15mm from the rear edge of the top panel. Tuck the sounder alongside the side panel as shown below.
- Before refitting the top panel, I interposed a small sheet of expanded polythene foam between the CTCSS board and the underlying circuitry as further insulation. Do not forget to reconnect the speaker before the top panel is secured.
Testing and Commissioning
- Switch on the rig.
- Set MODE to FM.
- Press RPT to select + or – repeater offset.
- Press ‘F’ then (REV) TONE. There should be an audible Morse code character and a bar should be displayed in the LCD below ‘TONE’.
- Press the ‘CALL’ button. Another Morse character should be heard. With successive presses of the ‘CALL’ button the CTCSS board will scroll through the 10 available tones. When the tone you wish to use is selected press and hold ‘CALL’ until you hear a beep. That tone is now set as the default tone until deliberately changed.
- Finally, the tone deviation needs to be set by adjustment of the trimpot on the board. Ideally this should be done using a deviation meter to set the tone deviation to 250-300Hz. Alternatively, the pragmatic approach is to slowly advance the injection setting to that which reliably opens repeaters, I found the setting to be rather sensitive in this particular transceiver needing to be set just above the minimum.
A set of operation instructions for this installation can be downloaded as a PDF. I recommend printing it double sided on A5 paper.
Bill of Materials
G8TMV tone board (http://www.tuckley.org/ctcss/)
NPN transistor (PN2222 or similar)
Piezzo buzzer –must be rated to work below 5V e.g. Pro-Signal ABI-009-RC (CPC or Farnell)
Thin multi-strand wire in various colours