Viewing 15 posts - 1 through 15 (of 25 total)
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  • #11281

    Sterling Spurrell
    CVRS Member

    I have a zenith 6g038 that I am working on and it is all capped but the sound is not right . The speaker is supposed to have a 750 ohm output transformer but it is only 535 ohms so would that cause much of a problem?

    #11282

    Alistair Thomson
    CVRS Member

    Can you explain what you mean by “the sound is not right?”

    #11283

    Sterling Spurrell
    CVRS Member

    The sound seems to be muffled and the radio does not seem to be has loud as it should . Also at about half way on volume control it get really distorted.

    #11290

    Alistair Thomson
    CVRS Member

    Another question – when you say the radio is “all capped” do you mean that you have replaced ALL the caps? If not, which ones did you replace?

    #11291

    Sterling Spurrell
    CVRS Member

    All the caps have totally but I noticed a few resistors out a bit. All I subbed in another speaker and have the same sound.

    #11292

    Dan Walker
    CVRS Member

    You mentioned the volume control gets distorted. Did you clean it?.
    Did you align the radio ? I have found that alignment makes quite a difference
    Dan in Calgary

    #11293

    Sterling Spurrell
    CVRS Member

    The radio is a zenith 6g038 and I do not understand alignment when it says one turn for second procedure and third procedure. Then it says coupled for fourth. To for fifth. Waverrod for six and seven which I assume to be antenna

    #11294

    Alistair Thomson
    CVRS Member

    Operation 1 involves a wired connection from the signal generator to the converter grid via a 0.5µF capacitor. The other operations involve injecting the signal via “one turn (of a wire loop connected to the terminals of the signal generator) loosely coupled to (close to but not tight up against) the waverod (the antenna loop).”

    The reason for this is that the first operation aligns the IF, and that needs a signal injected directly into the converter stage. The other operations just take a signal from the antenna.

    #11295

    Sterling Spurrell
    CVRS Member

    I am not sure I understand but not sure it needs to be aligned has it receives short wave really good now and it brings in the only am station without antenna or anything connected to it. But I noticed r-12 should be a 140 ohm w.w. resistor and there is a regular 220 ohm resistor there and it is getting hot.

    #11296

    Dan Walker
    CVRS Member

    If it receives short wave good then I would not be adjusting 2, 3, 4, or 5.
    I usually just set up the IF alignment.
    There are a lot of people who know a lot more than I do about these things ,: just speaking from experience
    Dan in Calgary

    #11297

    Alistair Thomson
    CVRS Member

    R12 is a 2.5W resistor, so if the replacement is getting too hot it’s the wrong wattage as well as the wrong resistance value!

    #11298

    Sterling Spurrell
    CVRS Member

    I will check resistor but would the wrong resistance in the output transformer have something to do with speaker problem?

    #11299

    Alistair Thomson
    CVRS Member

    No. The resistance value of 750R shown in the schematic is the input impedance of the transformer, which for a coil will be substantially lower when measured by a DC voltmeter than the actual resistance applying at audio frequencies.

    Have you tested the PSU voltages at C36, C37 and C38?

    #11300

    Sterling Spurrell
    CVRS Member

    The PSU voltage.
    c-36 76dcv
    c-37 52dcv
    c-38 102dcv

    #11301

    Alistair Thomson
    CVRS Member

    Hmmm. Can you measure the AC voltages?

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