Zenith Royal 400 s/n Z551549 I soldered broken orange wire to battery holder. Replaced all four electrolytic capacitors. Silent speaker and nothing from earphone jack. I checked the voltage at the collector of the driver transistor, it was zero. One pin of the driver transformer primary measures 5.8 V, the other pin measured 0. Checked,
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For FB group Building Transistor Radios This is the idea that I had about using more than one transformer to connect their windings in series or parallel to get a higher impedance and a higher stepdown ratio. My idea was to be applied to the Bogen T725 line matching transformer, but it could be applied
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I bought several of these miniature audio transformers from Electronic Goldmine. They are encapsulated so I can’t see anything, windings, core or materials. There are 5 pins, 2 on one side and 3 on the other, but the center pin measured open, so it’s apparently there to make sure the transformer is inserted the right way. The
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I was asking about very old capacitors and their shelf life on FB vintage test equipment group. The guys tell how good the old capacitor testers are because they have the “magic eye” to check for leakage. I was thinking that it would be easy to test any capacitor for leakage. All that’s needed is
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from a comment I added to this YouTube video https://youtu.be/GCh2LVHUavQ The main difference between a power transformer and an audio transformer is the way the E and I laminations of the core are arranged. The power transformer has an E on the left and I on the right of the first layer, then an I
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