Thank you for you help,
Charles
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Nice site here. I put all new caps in this Stewart Warner 9000-B. Tubes test good and all voltages are very good. It works but the volume is low. I touch my test antenna wire (20 foot wire) to the blue wire on the #4 BC antenna coupling coil and volume increases. Not to normal but louder. I started taking readings on these coils and one seems to be very high. The #7 BC RF coil pins G to J reads 110 ohms. Shouldn't this be much lower?
:Thank you for you help,
:Charles
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Charles
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:Sir Charles. . . . .
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:'soitanly looks like it. With the secondary of the #7 RF Plate transformers to mixer grid, having its secondary winding open.
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:The present resistance reading is very likely attributable to there also being a copper sulfate/fide deposit / trail
:bridging across the prior connection.
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:An inspection of that circitry does not reveal another possibility of a "phantom" circuit resistance loop being shunted across those coil terminal points.
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:You could refer to transformer #4 and compare its like function, which in this case, its B-C terminals should give a comparative normal resistance, as is to be expected.
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:If this is the situation, with that #7 transformer secondary being open, it is probably right at a wire end /to/ coil terminal interfacing point.
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:A repair procedure would initially consist of the use of a VEWY BWIGHT, high intensity light and a VEWY strong magnifier.
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:See if you then detect the presence of a chemically eroded wire, with its accompanying tell tale blue-green or green colorization of a CU SO4 residue presence.
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:In the case of an open, there is the possibility of that wire end being either an outermost part of a winding, where the available wire length is alterable. the other situation, of it being an inner winding end, in which you have the finite length of that wire end "stub".
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:I have repaired, many a "stub" , thru the years.
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:My usual procedure is to initially wet rosin flux that wire end and then apply fresh solder . .with ITS core rosin . . and then see
:if the tip of the wire then takes on the slight tinning, with its silver appearance, as viewed under the magnifier again. If not try again, and usually the tinning will creep on inwards, if only a trace was being obtained the first attempt.
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:With a tinned wire "stub" you then move over and get a fine bare coopper wire . .a single copper strand from an AC line cord . works great.
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:You then rosin up that wire and fully tin it. Take one end of that wire and firmly mechanically connect and solder it to the coil terminal.
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:The other end of the tinned wires length is pre estimated for length, to reach the stub wire and then that bare tinned wire end is fashioned into a 1/16th inch closed "needle loop" that will then be centered around the coils tinned wire "stub".
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:A drop of rosin flux and a fresh drop of solder is used to reflow solder the two connections. Deflux, and if so desired, a small protective drop of Duco cemant can be added.
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:Using that adhesive medium, would permit a removal time encompassing ~5 years, with the use of a solvent of Acetone, MEK , Xylene or Lacquer thinner.
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:An incorrect choicing of an adhesive of the aliphatic family or the super glue family, would require a cold chisel.
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:Thassit . . . .
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:73's de Edd
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:Nice site here. I put all new caps in this Stewart Warner 9000-B. Tubes test good and all voltages are very good. It works but the volume is low. I touch my test antenna wire (20 foot wire) to the blue wire on the #4 BC antenna coupling coil and volume increases. Not to normal but louder. I started taking readings on these coils and one seems to be very high. The #7 BC RF coil pins G to J reads 110 ohms. Shouldn't this be much lower?
::Thank you for you help,
::Charles
::
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