11-06-2014, 09:05 PM
Are you sure you have the electrolytics wired correctly? Something does not look right in the photo. According to the schematic, the negative of the 20 uF capacitor C49 should be connected to R37 mounted on the chassis. The photo shows a 10 uF connected there instead. The 10 uF and 25 uF caps should have their negatives connected directly to chassis. Only the 20 uF cap should connect to R37.
You could substitute a resistor of equal resistance for the field coil, but it will increase the hum level as it is not as efficient as a filter. Since you are troubleshooting a hum problem, it might not be the best way to test. Why not just connect the speaker and measure output at the voice coil itself?
You could substitute a resistor of equal resistance for the field coil, but it will increase the hum level as it is not as efficient as a filter. Since you are troubleshooting a hum problem, it might not be the best way to test. Why not just connect the speaker and measure output at the voice coil itself?
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