Cobra 148GTL. Repairing someone elses "Mods" again.

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  • Опубліковано 24 лис 2024

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  • @MarkOgnan-hb4mq
    @MarkOgnan-hb4mq Рік тому +4

    Hey Mike....was flipping through UA-cam the other day, and came upon this video. Yeah, it's me, the owner. I had watched it after you repaired it for me, but watching it again it strikes me that I probably didn't thank you properly for a) the integrity and thoroughness of your work, and b) going through and cleaning all the glue and mess....know it was bad, but sir....I truly appreciate it!! Today is 4/15/23, and for your information and all your followers, the radio has been used daily since I got it back from you, and has had no problems. Check that, seems I had you replace the on/off vol knob after a while, but....other than that it talks and receives just as it was designed. I run it on my Ram with a sirio 5000, swr is just barely over 1:1 on channel 20, and I have never had a bad get back report always hear how good it sounds. Twice now in the past during my commute I have talked straight line to base stations, one was about 45 miles away, and the other was approx 60 miles away in another state. Thank you Mike, truly. I know the old snake isn't the latest and greatest, but we've got a lot of miles together and I appreciate you going the extra mile, craftsmen like you are getting fewer and farther in between. Mark

  • @greedyfirstalgorithmlast26
    @greedyfirstalgorithmlast26 4 роки тому +5

    Oh God, MIKE! Please , Please, Please. Ya'll Come Back son. We'ins shore miss ya! Waco Ham Operator

  • @homefront3162
    @homefront3162 6 років тому +12

    Damnit Mike... all I do anymore is watch your videos

    • @martyham10
      @martyham10 Рік тому

      ME TOO! I'm a "Mike addict"!

  • @Dennis-mq6or
    @Dennis-mq6or 5 років тому +2

    Mike,
    If I am not mistaken, the cd4094 is basically a serial to parallel converter. ( a shift and latch device)
    It shifts in one data byte per clock pulse, and after shifting in 8 bits of data into the serial shift register, it is given a latching pulse to move the serial data into the parallel output pins.
    Properly designed, you would only get one burst of noise every time you changed the channel.
    Poorly designed, the clock, data, and latch pulses would run continuously.
    Any one of those 3 could cause the noise you are talking about. And it would be broadband noise which you can't filter out and the best you can do is try to shield it.
    I an a 72 old retired engineer, and grew up with those devices, so I know a few tricks that might help you de-noise it, or at the very least reduce the noise.
    Wherever your signal is being generated from you add a 33 ohm resistor in series with the transmit line to lower the slope of the square wave to eliminate a whole bunch of the harmonics that are in all square waves.
    The signals to the 4094 will be generated in that external box.
    If you have any data signals going from the board in the radio to the external box the 33 ohm resistors would be added there.
    33 ohms is a compromise value that always works to eliminate SOME harmonics.
    The higher the value of resistor you use, the more harmonic noise will be removed, but it lowers the amplitude of the signal and you lose noise margin when you do it.
    If you are not sure which wire is which, you can probably add 33 ohms in series with each wire ON BOTH ENDS.
    (except for power and ground which should get ferrite beads on both ends)
    I hope this old engineer trick solves your problem!

  • @UDX-340
    @UDX-340 Рік тому

    This video,kept me from going crazy on a VFO ..thnx so much.

  • @greedyfirstalgorithmlast26
    @greedyfirstalgorithmlast26 5 років тому

    Again your video teaches tricks I didn't know, & I went to Army-Navy Electronics School in Arkansas 1973-1975 and the instructor, Mr. Green, knew every trick in existence, of 1975.

  • @w.rustylane5650
    @w.rustylane5650 4 роки тому

    That's the very reason I use a stand alone freq counter under its own power in line with the coax from the radio to the antenna through a BNC connector. I don't want any extraneous noise injected into my radio. 73 Mike.

  • @hancecrawford
    @hancecrawford 7 місяців тому

    Hi Mike what a mess many headaches

  • @DonDegidio
    @DonDegidio 6 років тому +4

    Hi Mike,
    I admire you ability to work through others "repairs". Another fine video. 73 WB3BJU

  • @Inavato
    @Inavato 3 роки тому

    WOW! A 148s Bandwidth is fine I would not try to fix it it's great .. Just increace the cap size to give a little more bass when using a D104 mic

  • @kd2eat
    @kd2eat 6 років тому

    Thanks for the tip on the Kynar wire. I've used 30ga wire-wrap wire for patches like that, but suffered from the insulation melting back. I'm gonna order up a roll with Kynar.

  • @jamesbeemer7855
    @jamesbeemer7855 5 років тому +1

    I used my radio to talk to home . I was in the Army .

  • @davebutler6661
    @davebutler6661 4 роки тому

    If you want to check how well you know your stuff then try explaining it to others....excellent job.

  • @williamsquires3070
    @williamsquires3070 6 років тому +1

    It’s more accurate to say that the LED displays are multiplexed, not PWM; though if they offer a ‘brightness’ control, then they’re PWM, and multiplexed! 😋 Either way, it generates switching noise. Mounting the outboard electronics in a metal project case may help, as would a ferrite-bead on the cable. You might even try twisting the wires much like twisted-pair phone/networking cable.

  • @francismcclaughry3794
    @francismcclaughry3794 5 років тому

    I have one-off these radios. I'm sure I burned the final in it. Mine had the mods and it had a digital readout like that one. mine took the frequency and look for it. I had an army stick on the roof. it had been up there forever. The reason I said the finals went in this one is that I hooked modern cobra and it warned me there was antenna problem.

  • @joewilson2258
    @joewilson2258 6 років тому

    You can use a few ferrite beeds to attenuate the noise with in the box of outside box .

  • @larryak0z672
    @larryak0z672 4 роки тому

    Nice videos, but you seem to repeat things a lot . I'm learning much. Thank you.

  • @williamcolvin3609
    @williamcolvin3609 6 років тому

    When you mount boards in radios - where do you get the little miniature L brace to mount the boards with. The smallest I have been able to find is 20mm or 1 inch and the braces for the Echo and other boards are about 1/4 inch wide by 1/2 inch angle and usually threaded. I like trying to put things back as close to factory as I can. RF Parts site has not been working and Golden Eagle Radio did not show any mounting brackets.

    • @mikesradiorepair
      @mikesradiorepair  6 років тому

      Think I got them from DigiKey. That's where I get most of my small electronics type hardware. www.digikey.com/products/en/hardware-fasteners-accessories/mounting-brackets/574

    • @williamcolvin3609
      @williamcolvin3609 6 років тому

      Thank you very much - that is just what I was looking for very nice selection. I knew you made a lot of your parts so was not sure if you ordered thing you could make.

  • @jamesbeemer7855
    @jamesbeemer7855 5 років тому

    It had 120channles with the addition of side band . I saw that the addition of more than that interfering with televisions in the naebor hood . I can't spell 😂 .

  • @Tomahawk-415
    @Tomahawk-415 5 років тому

    Are alenco's electrolytic capacitors any good I got a kit of them and I was wondering? maybe i would replace some of the capacitors in my radio with them

  • @therealjammit
    @therealjammit 5 років тому

    Arf. That homebrewed board. At least fully tin the traces and clean off the flux.

  • @soylentgreen6476
    @soylentgreen6476 6 років тому

    Thanks for sharing.

  • @jamesbeemer7855
    @jamesbeemer7855 5 років тому

    Yes that's about when I got mine .

  • @adrongarretson6195
    @adrongarretson6195 5 років тому +1

    So damn it Mike how the hell does a guy get a hold of you to fix a radio I got a Icom 211 that needs your attention

  • @ProspectorsGhost
    @ProspectorsGhost 7 місяців тому

    Maybe somebody has already asked these same questions and you might have already previously answered them. If so, Please forgive me for asking them again as I'm unaware that these questions might have already been asked, and that the answers might have already been provided if that has been the case. So I'm asking them myself at this time.
    I've seen that glue in CB radios and other electronic component circuits. It looks and feels more like a soft wax type substance than a glue. But either way If that glue is causing so much of a destructive internal component problem then what is (or was), it's original purpose.
    Why is it still being installed into the radios and also if it causes so much of a corrosive destructive problem with internal components then why does the manufacturer keep installing it into the radios at the factory?
    Also if the manufacturer installed it in the circuitry and they know it causes problems why can't they have a process during manufacturing that is able to almost completely remove it after the circuit board has been manufactured and prior to the radio being packed and shipped, thereby eliminating the substance's corrosive destruction process. Or at least come up with and use a different non-destructive and non-corrosive substance.
    It sure would make your job easier as well as being less hair pulling. Just asking out of curiosity.
    Anyway. Thanks for a great informative video, and thanks for sharing it with your audience.

  • @MrRichard57000
    @MrRichard57000 Рік тому

    Don t understand the mod...imo you can mod it without much problems to 120 channels,becaude thr board is the same as an stallkerxx. Or the very old president... grant????anyway great video mike!!!!

  • @51nw
    @51nw 6 років тому

    how can i connect my frequency counter to my digital scope? there is a trig send jack on the back, will this work?

  • @johntownley83
    @johntownley83 4 роки тому

    Where do i find contact info so i can send some of my radios to you to get worked on and beefed up.

  • @VanishingNomad
    @VanishingNomad 6 років тому +1

    What is the purpose of the glue. Why do they put it in there?

    • @witeshade
      @witeshade 6 років тому +3

      generally they use glue in devices like that to give vibration resistance. A lot of through-hole components are heavy enough that they can move if the device gets dropped, or just years of tiny vibrations can crack solder joints and so on. The problem is that a lot of the glues that various companies used (across entire industries, not just radios) tend to become corrosive or conductive over time. Especially if they weren't mixed perfectly correctly in the factory, or they sat to long, or just because of the effects of time, they start to change and cause all kinds of nasty problems.

  • @xl5john
    @xl5john 2 роки тому

    148F has a frequency counter. Why put one in this radio.

    • @mikesradiorepair
      @mikesradiorepair  2 роки тому +1

      Because this is not a 148GTL-F. It didn't have one.

  • @devengames3776
    @devengames3776 5 років тому

    At89c2051 is microcontroller from mcs51 family

  • @donnidiffer506
    @donnidiffer506 5 років тому

    Mike how can I contact you?

  • @kirbyjeffery4773
    @kirbyjeffery4773 6 років тому

    Mike I have a question could someone use a ten turn trimmer resistor in place of jp3 in a Cobra 29 to achieve a variable power for the Dead key ? Thanks in advance just wanted to know if it was at all possible

  • @BOB12349307
    @BOB12349307 4 роки тому +1

    throw it in the dumpster and buy a stryker

  • @jamesbeemer7855
    @jamesbeemer7855 5 років тому

    It wasn't meant to be modified .

  • @dougthetechguy5005
    @dougthetechguy5005 6 років тому +2

    I would have removed that channel mod kit it looked like junk and who want's that box attached to it just flopping around, also there's so much labor in what your doing I can't see people willing to pay labor rates for all that work I don't know how you make it work from a profit point.

    • @Eric-zi1oz
      @Eric-zi1oz 6 років тому

      Some guys like their rigs modded.....

    • @jonka1
      @jonka1 6 років тому

      I suspect that the customer wanted to hold on to that mod having chosen and paid for it.

    • @asherdie
      @asherdie 5 років тому

      He doesn't say can't.

  • @jacknifedbl
    @jacknifedbl 5 років тому +1

    So when my icom ic 735 takes a crap I'm gonna send it to you and pay you why you charge..I have see too many of your vids lol

  • @kd5ozy
    @kd5ozy 6 років тому

    Is that thing worth it?

    • @martyham10
      @martyham10 Рік тому

      If you want it and like it, it's worth it...

  • @Ronnie9710
    @Ronnie9710 6 років тому

    I bet when he gets that bill,he'll think he bought a new radio.all the way to 10m cw band.woops!Just joking with you Mike.CUL Ronnie kn4u.

  • @johnjimjohnston
    @johnjimjohnston 6 років тому

    after all that still not working well //////// //////????????

  • @buckaroobonsi555
    @buckaroobonsi555 6 років тому

    Conformal coating would have helped.