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Digimax lite????

Discussion in 'General CB Services Discussion' started by BammBamm, Nov 8, 2010.

  1. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    I assume the radio will need an alignment after the installation of the kit? Prices are even better after I clicked "Currency in US dollar".

    http://www.circuitdomain.com/Shop/index.php?currency=USD&cPath=1


     

  2. silverstreak

    silverstreak Member

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    I was thinking of getting one for my TCR-458 wich is like new no mods.Do they give you instructions how to install in the 858 Board?
     
  3. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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  4. Allan Esterhuizen

    Allan Esterhuizen New Member

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    you can do the separation yourself , no need to pay for him to do it unless you already want it built and tested
     
  5. tramd

    tramd Active Member

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    I put one in a TRC 458. The only problem was that the face plate sits so far from the chassis that the original knob won't fit back on as the new shaft is shorter than the original one. I couldn't find anyplace that sells a longer one of that exact type. I ended up taking a short piece of a Bic pen and heating it to make it fit tight over the new shaft to extend it. I also had to put a grommet in the face plate to remove any wobble. It works fine. The only complaint that I have is there is a buzzing after installing the DigiMaxLite. I contacted the company and was told be it was because of it being digital and suggested I buy a filter that they recommended for the incoming power to the DigiMax. I did that and it lessened it but it is still slightly noticeable. I later found the noise comes from the LED display as when I unplug the display from the main board it goes away completely.
     
    Shadetree Mechanic likes this.
  6. tecnicoloco

    tecnicoloco Tweaknician in Training

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    Try this:
    Hope this helps !
     

    Attached Files:

  7. nomadradio

    nomadradio Analog Retentive

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    The filter shown would probably do the job.

    Just make sure the display's circuit board is not grounded to the radio's metal chassis. The display must be mounted so that the board's ground foil is INSULATED from the radio's metal chassis.

    We found that running the hot and ground wires all the way to the big filter cap near the rear of the circuit board shuts down most of the digit-scan noise. What you're hearing is the on/off switching current as the digits are scanned.

    And if that big filter cap is approaching 30 or 40 years old, it could be time for a new one.

    This has worked well for us.

    73
     
    Shadetree Mechanic likes this.
  8. silverstreak

    silverstreak Member

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    Thanks all for the reply.I will report back when I get one at this time he is out.
     
  9. red97k1500

    red97k1500 Active Member

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    I never could get the squelch to work right on mine, this is what Mac sent me but there is no way this is the right squelch tap point...

    Squelch tap is IC5 (MB3756) pin 5.
    Use volt meter to work out if it's hi or lo and adjust R16 as per documentation.

    Regards,
    Mac

    The squelch tap is tr15 on a cobra 140 gtl just like loose cannon told me... so I hooked it up to pin 5 of ic5 against my better judgement, then hooked it back to to tr15... I think I fried something hooking it pin 5 of ic5, because now when ever I turn the squelch all the way up the display goes blank. The voltage never changes on pin 5 of ic5 when you turn the squelch pot... if my memory serves me correctly it is about 12 volts or maybe it was 8 all the time
     
    #24 red97k1500, Jul 17, 2019
    Last edited: Jul 17, 2019
  10. nomadradio

    nomadradio Analog Retentive

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    The MB3756 contains three 8-Volt regulators and the transmit/receive switching.

    Has nothing to do with squelch at all.

    I would use the collector (center pin) of TR14.

    You'll have to indicate the squelch polarity to the Digimax setup as high with squelch closed, low when squelch is open.

    73
     
  11. red97k1500

    red97k1500 Active Member

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    Do you think hooking up the squelch wire to 8 volts could hav fried something?. From what I remember it is squelch high... I haven’t messed with it for about two months now. I never could get r16 on the digimax board adjusted quit right . I would have to have the squelch pot turned almost all the way up to use the scan function.
     
  12. nomadradio

    nomadradio Analog Retentive

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    The squelch circuit in this radio mainly uses a change in circuit current to open or close the squelch.

    The actual up/down voltage change is not so large. Makes it harder for the scan function to tell the difference.

    How important is the scan function for this radio?

    73
     
  13. red97k1500

    red97k1500 Active Member

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    The scan function is not that important to me personally... it just concerns that now after hooking it up to ic5, and then rehooking it to tr15. If I turn the squelch pot to far to the right the channel display completely blacks out... and I think the rx/tx light does as well, if I remember right. And it didn’t do that untill I tried connecting the squelch tap wire to pin 5 of ic5. Now if I leave the squelch pot turned all the way to the left the radio seems to work just fine.
     
  14. nomadradio

    nomadradio Analog Retentive

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    First time I've heard of this fault.

    If it works without the squelch connected, I'd count my blessings and just skip the scan feature altogether.

    73
     

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