575-m6 help

[1iwilly]

I am working on a static 575-M6 with the green board. When I move the tone slider to 0, I don't notice any hint of bass. However, as soon as I start moving the slider up, I notice that the treble becomes stronger. I changed the two 4.7 µF electrolytic capacitors, thinking that they might be related to the bass control, but there was no change. On my Icom 7300, in the EQ menu, if I set the bass to 5, I can slightly hear a hint of bass when in monitor mode. What else can I test? When checking the tone slider? Checking it with my ohm meter at 0 read 2.106 in the middle, 364.2; and at 9, 064.0

 

[loosecannon]

check the slide potentiometer with an analog meter.

digital meters are terrible at diagnosing flaky pots, while an analog meter will tell you pretty much instantly whether or not the change in resistance is smooth across the range or not.

also, just spraying contact cleaner in these and moving them up and down a bunch in an attempt to clean them can damage the carbon tracks.
Better to just use an electrical lubricant as that will clean it up without damaging it.

you might try substituting three different resistor values for the slider, one near the low setting's resistance, one near the middle, and one near the max range's resistance.

this would tell you whether or not the slider is the problem.

the lack of bass could also be due to the mic element itself starting to come apart or having sustained some sort of damage.
LC