HI all. I have a DigiTech RV-7 HardWire Stereo Reverb that I like alot, and have rehoused (long story) but the selector knob for reverb modes is failing. I'd like to replace it, and it is a b100k 9mm alpha 7 detent potentiometer, which I can't find a replacement for. I tried putting together a custom stepped attenuator (measured ohms at each stop), but it doesn't work at all. I'm not sure if I'm just not hooking it up right (the input/wiper is straightforward enough, but the third wire?). I'd love to just find an exact replacement, but smallbear and others only have 11 step pots. Anyone have any experience with this stuff? Thanks in advance!

I think you were on the right track measuring the resistance at each detent. I think this will be a voltage divider arrangement and all three wires to the pot will be critical.

There will be a range of movement on the pot that triggers the digital settings ... I expect these are designed fairly wide to allow easy manufacture with reasonable tolerance of components - I would guess +/- 10% or more. (100/7 = >14)

I would suggest you get a variable 100 k pot and find out the exact range that tiriggers each sector - the resistance on both sides. This will give you a range of max and min for each sector (and all will add up to 100K).

Then when you have this data, you can find a 7 position switch and come up with an arrangement of fixed resistors that will give you a total of 100K but let you tap into that at places that give you a resistance in the middle of the ranges you have found.

OR ... do you need the detent anyway? EHX have pedals that do crazy switching but they don't bother with detent pots ..

Kiwi - thank you for your reply. i''m thinking that if it's a voltage divider situation, then I should get a 2 deck/7 position switch. I think the extra deck is what I've been missing as i've just been using the switch I have as a rheostat not a VD. Thanks for the tip!