42-380 tone controls - Printable Version

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+--- Thread: 42-380 tone controls (/showthread.php?tid=16)

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42-380 tone controls - Guest - 10-07-2005

I have just completed rebuilds on some 42-380 chassis, including all new capacitors and resistor value check, and can't get the treble and bass tone controls to provide very much effect. This is the 4th one like this i've found. Any solution(s) would be appreciated. BTW, all the rebuilds have been VERY strong performers on both BC and SW.

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- Chuck Schwark - 10-07-2005

Looking at the schematic, the TREBLE control should always have some effect, unless pot #53 is bad/open. The cap in series with this control should be replaced. It will be leaky or shorted.

The TREBLE pot could have been damaged in the past if leaking caps #51 and 52 allowed B+ current to pass through the pot as well, burning it.

The BASS tone circuit (loudness compensation as well) will have less effect if the volume pot has been changed out and is not a tapped type.

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