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• Low band - This will give you 26.515-26.955.
• Mid band - This will give you 26.965-27.405.
• High band - This will give you 27.415-27.855.
• UK band - This gives the UK 40 band which is 64 channels above the FCC (Mid) band and is 40 consecutive channels without the Alpha channel hops (clarified to 27.60125, FM radio needed).

• TC9106
• TC9119

1. Check that the radio is using either the TC9106 or the TC9119 PLL.
2. Decide what bands you require the board to produce (see note below).
3. Decide how you are going to control the new bands, existing panel switches, new toggle switches, replacing the rotary band switch (only for pros !) etc.
4. Remove the PLL from the main PCB of the radio, make a note of where pins 1,2,7 and 9 are.
5. Solder the ribbon cable to the vacant PLL pins holes 10-17 (D0-D7, see picture later).
6. Attach the 4 outputs from the board to the vacant PLL pin holes, number 1,2,7 and 9.
7. Solder a jumper wire between PLL pin locations 5 and 6 to the 0V (earth) track.
8. Solder a jumper between PLL pin locations 1 and 4.
9. Solder the EPROM board earth (0V) to any other good earth point on the main board.
10. Solder the +12V wire to the main radio supply, make sure that it is from after the on/off switch so that the board is not powered when the radio is turned off.
11. Left one leg of the capacitor that is in series with the 10.240MHz crystal and add a 39pF ceramic capacitor in series with it, when in the UK band have the switch short out the added cap, but when on the low,mid or high bands the new cap will be enable causing a frequency increase to get the correct alignment.
12. Connect the board to the switches to select the required bands and functions.
13. Go back to step 1 and double check everything on each step.
14. Triple check everything, I mean it !

After doing this you should have the board connected to +12V, earth, 8 inputs from the PLL pin holes to the EPROM (D0-D7), 4 outputs from the board to the PLL pin locations 1,2,7 and 9, the EPROM control lines connected to your switches:

Testing and additional info

11. Turn the radio on and test everything thoroughly, all bands, both existing and new, Low band, Mid band, High band and UK band.

12. Tune or broad band anything that needs adjusting (see tips later in manual).

13. If all is OK and you did not make any mistakes, CAREFULLY Stick down the EPROM board with the double sided foam tape supplied, do not apply too much pressure.

14. Close up the radio and enjoy your new frequencies !

Notes

Broad banding

Most radios will need it to be done, but you may not need to, an easy way is to tune the radio for the upper frequencies (but as low as you can without problems) and then add the circuit below to the low bands to extend the tuning range of a problem tuning can.

Also some tuning cans may only be using part of the internal coils, if only one of the outer pins is connected and the middle pin is used, cut the track that goes to the middle pin and connect the track to the unused outer pin, this increases the bandwidth of the can making it cover more channels.

Here is some ASCII art:

   
                  _______
   Unused pin--> | o O O |
                 |       |     <----Screening can viewed from trackside

                 | O   O |
                  -------

 

EPROM band selection codes and programming

This table shows you all of the possible programming arrangements with this EPROM board and what input codes enable which bands, the inputs only need to be pulled down to 0 Volts, they do not need to be pulled high by the switch, so for the UK band both of the band wires could be left disconnected, for the Mid band you only need to pull B2 low.

Example modification

1. I checked the PLL was a TC9106 (or TC9119 for UK).

2. I decided that I only wanted to have the UK and the Mid bands.

3. I checked the programming chart and found that for the UK and Mid bands I only need to control B2.

5. I made available the switch required for the new function and wired it to the Eprom board as shown below:

             UK/Mid    <---Switch function
              ___       ___ 
             | O | <--- UK (switch up)
   B2  <=====|=O |
   0V <======|=O | <--- Mid (switch down)
              SW1

6. I removed the PLL making a note of which way around it was, pin 1 of the PLL is always the pin on the corner at the bottom left when viewed with the markings the correct way up, there may also be either a notch or a dot at that side.

7. I connected the EPROM inputs (A0-A7) to the PLL pin locations as follows:

8. I connected the outputs of the board to the PLL pin locations shown below:

9. Then I connected the power wires (+12V and 0V) from the board to the radio.

10. I solder the jumpers between the PLL pin locations 5,6 and earth, and between 1 and 4.

11. I lifted one end of the capacitor that is in series with the 10.240 crystal and added a 39pF cap in series with the original, then added the switch wire across the new cap so that when in the UK band the new cap is bypassed, causing a 4 kHz increase in frequency when on the low, mid of high bands.

12. I double checked all of my wiring and that I had got the input and output connection the correct way around etc.

13. I slipped the EPROM board into a bag to protect it.

14. I turned on the radio and checked for both normal operation and the new expanded functions I set up (UK and Mid bands).

15. I checked to make sure that the EPROM board was not receiving a 12V supply after I turned the radio off.

16. All was working correctly so I stuck the board down in the radio using the double sided tape to finish the installation.

17. I did not need to broad band the radio, so I have finished the installation.

18. I closed the radio back up.

Trouble shooting

EPROM board is not working at all

Check jumpers on pins 1 goes to 4 and jumper on pins 5,6 go to 0 Volts track

Check that you have not miss-programmed the jumpers or switches, 1 incorrect jumper or selection setting could stop the EPROM from recognizing the binary codes.

You have not attached the outputs form the board to the correct PLL pin locations.

Only some bands are working

There could be a mistake with the programming switches not giving the EPROM a 0V signal, or a jumper has not been or added correctly.

You did broad band the radio and the miss-alignment causes the radio to not work on some bands.

Some channels do not work on a certain band

If there is a large gap of channels missing it may be a jumper or switch programming problem.

The radio may need to be re-tuned slightly or broad banded.

The EPROM may have been damaged by static electricity during handling.

The EPROM may have been damaged by incorrect wiring.

Note: All EPROM's are checked after I have programed them to ensure that they have accepted the programming information correctly and that the EPROM is not faulty.

E-mail me if you have any questions or concerns about installation.

All boards are installed at your own risk,
(it is not my fault if you make a mistake and damage your equipment).

I build and test these circuits myself before shipping them, so I know that the boards are working correctly when you receive them.