How to use Codan 8525 on ham bands

Discussion in 'Ham Radio Discussions' started by PD9X, Jan 10, 2017.

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  1. KX4Z

    KX4Z Ham Member QRZ Page

    Rats. Sorry !!
  2. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    I have managed to drive the relays and such with an Arduino Nano, but am still having problems with the PLLs.
    The EPROM and 80C31 are removed. I hope to make an Arduino plug in board to replace them.
    It is quite a learning curve!
    One problem was the 8525A has I2C, CBUS and the PLLs all on the same clock and data lines. The Arduino locks out the A4 and A5 pins (used for I2C) so they cannot be used for anything else once the I2C has been started. So far, I have not found how to turn the Nano procerssor's I2C hardware on and off.
    So I've added an MUX..
    and can select the function with...

    digitalWrite(MUX0,LOW); // 0 = I2C, 1 = Other, 2 = +5V, 3 = gnd.

    This looks to be working ok, but driving the 2 x MC145159 PLL chips (in series) has proved to be a problem for me as I have not figured out the numbers required as yet.
    Just yesterday, I purchased a second one, an 8525B version, so I do need to get it all going.
    VK6LIN likes this.
  3. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    I finally found the EPROM programming info!
    Codan no longer support this as it is too old. At least that is what Codan here in Oz told me.

    Attached Files:

    Last edited: Nov 20, 2019
    W1TRY and VK6LIN like this.
  4. VK6LIN

    VK6LIN Ham Member QRZ Page

    Hi vk3zyz, thanks for sharing your resources regarding to Codan 8525/8528 radio.
    I'm a keen on Codan tinkering since I'm getting into this hobby, I'm still sort of new Ham, HiHi.
    Over the years, from second hand market, I got four 8525/8528, and three of them have 1647KHz crystals fitted (only by seeking ones already fitted LSB option), two of them has remote heads (8532 and 8533 each).
    I have 651pcfil programmer with me as well, version 3.23 (the one you shared in above post was v3.21). Anyhow, unlikely any significant difference between the two. v3.23 is not easier to use by any standard.

    With 651pcfil and a EPROM reader/writer, I managed to reprogram two of my four units. So both of them, can Rx/Tx on 80m/40m LSB, also 20+m USB, as you can see from enclosed photo.


    So I believed I managed to enable the so call "TXE" option. All the magic was locked inside the EPROM.DAT binary file eventually been written to EPROM.
    -- above line quote from manual

    Anyhow I'm still working on my other two units (one is 8528S-H) to enable TXE option, likely involving manipulating the EPROM file in raw Hex format. Not sure are you still into tinkering them, and how is your new 8525B going? If you have capacity to manipulate EPROM, I'm certainly happy to share my resources.
  5. W4HWD

    W4HWD Platinum Subscriber Platinum Subscriber QRZ Page

    Pardon my ignorance, but what was this rig originally designed to do?
  6. VK6LIN

    VK6LIN Ham Member QRZ Page

    For 4 wheel drive communication in outback Australia, contacting the emergency services like Royal Flying Doctor Service.
  7. W4HWD

    W4HWD Platinum Subscriber Platinum Subscriber QRZ Page

    Sweet. No wonder I had no clue!
  8. VK6LIN

    VK6LIN Ham Member QRZ Page

    Yep. It had only some dozens of funny spot frequencies (channels) programmed in EPROM between 2MHz and somewhere 24MHz out of factory.

    But when released, has heaps options to spend money on just same as Elecraft style.

    Anyway they are well designed and made, lots of fun to tinker them around.
    W4HWD likes this.
  9. VK3ZYZ

    VK3ZYZ Ham Member QRZ Page

    I'm pleased you found some help here.
    I have some more info on my progress on our local club site...
    This is the 8525B. I'm also working on an 8525A that has no front at all, so I've got to build that, as well as figuring out the driving of the IO chips that are different (Saa1061) to those in the 8525B (SAA1064).
    My Codans do not have the multi digit display, just 2 digits, so to get full tuning, I need to remove the original processor and run an Arduino instead, or in the case of the better VFO, the ESP32 board, later!
    So far, I've given up with attempting to drive the Codan PLLs directly, so the latest mods have them disabled and the signals are generated using the Si5351 board. It generates the first mixer, second mixer and the USB/LSB signal. This one (above) has a new board that replaces the front panel Codan board, and has an OLED display in place of the 2 digit LED display, and the original buttons are used.

    Another parallel project is a really neat VFO shown here...
    I cannot claim the magnificent dial. That was from JF3HZB. Thank you :)
    There are still some programming steps to be overcome but as now a couple of others are working on the board too, that will be fixed soon. I'm not a real good programmer and there are many parts on the program needed to be modified that are way beyond my abilities.
    Last edited: Dec 10, 2020
    VK6LIN likes this.
  10. VK6LIN

    VK6LIN Ham Member QRZ Page

    You have done some amazing work there, vk3zyz. It's impressive! I'm not intent to go down that far at the moment. Still focus on the Hex dump of the EPROM currently. You have fun!

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