March 29, 2019 at 3:00 pm #11281
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?March 29, 2019 at 3:12 pm #11282
Can you explain what you mean by “the sound is not right?”March 29, 2019 at 3:24 pm #11283
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.March 30, 2019 at 6:14 am #11290
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?March 30, 2019 at 7:19 am #11291
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.March 30, 2019 at 8:27 am #11292Dan WalkerCVRS 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 CalgaryMarch 30, 2019 at 9:24 am #11293
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 antennaMarch 30, 2019 at 10:28 am #11294
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.March 30, 2019 at 10:36 am #11295
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.March 30, 2019 at 11:01 am #11296Dan WalkerCVRS 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 CalgaryMarch 30, 2019 at 11:16 am #11297
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!March 30, 2019 at 11:25 am #11298
I will check resistor but would the wrong resistance in the output transformer have something to do with speaker problem?March 30, 2019 at 12:02 pm #11299
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?March 30, 2019 at 12:50 pm #11300
The PSU voltage.
c-38 102dcvMarch 30, 2019 at 1:19 pm #11301
Hmmm. Can you measure the AC voltages?
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