So on my 290-T chassis, I have issues with the power switch on the volume control. I got brave and took the pot apart to see if I could fix the switch. In the process, I broke the PCB of one of the channels. Which is just as well because no matter how much I cleaned it, I couldn't get static totally out of it. Since this part is rare and hard to inexpensively replace with an original part, I have some questions.
I happened to have in my workroom a dual gang 100K ALPS 4 lug audio pot. I expected that it wouldn't work correctly because of the impedance difference. However and to my surprise, it seems to work fine in the Fisher!
Long term I need to source another pot because the shaft is too short and narrow for when the chassis is returned to the console. It seems sourcing a brand new dual gang 4 lug 500K 35mm x 6mm shaft with a D end with a rotary power switch capable of switching AC power is not going to happen.
However, it seems that if I could get away with a 100K or a 300K pot, I might be able to do it (though without a power switch). Also, pots with 4 lugs are rare. I'm not exactly sure what it is for but I get the impression it is probably for the "loudness circuit" which in my system consists of a resistor and a couple ceramic capacitors. Do I really need that?
If that loudness circuit is something one should retain and if I could not find a 4 log pot, I noticed the bass and treble controls use the same pot as the volume pot sans the power switch and sans use of the 4th lug. If I could install say a brand new 3 lug 100K or 300K pot for the bass and treble, then I'd have a factory original for volume available with the 4th lug and a spare pot to boot. Any thoughts?
I happened to have in my workroom a dual gang 100K ALPS 4 lug audio pot. I expected that it wouldn't work correctly because of the impedance difference. However and to my surprise, it seems to work fine in the Fisher!
Long term I need to source another pot because the shaft is too short and narrow for when the chassis is returned to the console. It seems sourcing a brand new dual gang 4 lug 500K 35mm x 6mm shaft with a D end with a rotary power switch capable of switching AC power is not going to happen.
However, it seems that if I could get away with a 100K or a 300K pot, I might be able to do it (though without a power switch). Also, pots with 4 lugs are rare. I'm not exactly sure what it is for but I get the impression it is probably for the "loudness circuit" which in my system consists of a resistor and a couple ceramic capacitors. Do I really need that?
If that loudness circuit is something one should retain and if I could not find a 4 log pot, I noticed the bass and treble controls use the same pot as the volume pot sans the power switch and sans use of the 4th lug. If I could install say a brand new 3 lug 100K or 300K pot for the bass and treble, then I'd have a factory original for volume available with the 4th lug and a spare pot to boot. Any thoughts?