Alesis Ion volume pot replacement

[Jokeyman123]

Was a challenging project, as this volume pot has 6 very thin soldering arms close together, the IC board traces are also very thin and fragile. I could not find the original design volume pot, which was a metal canister design with a brass mounting sleeve. The only replacement I could find-which came from Germany oddly enough (odd since the Ion was originally a US manufactured synth) was a plasticky cheaper construction, with no threaded sleeve to secure the volume shaft to the top panel. After studying what I'd have to do to desolder and resolder these 6 tiny pins, I opted for an alternate plan.

There are 2 thick mounting clips in addition to the 6 solder pins, these secure the pot to the IC board. I was able to clip these off on the top side, and with a surgical clamp I keep in my toolbox, clipped to each of these, I was able to desolder and pull these pins out, and clear the empty holes enough to fit the new pot mounting pins. This was the easy part.

Now I faced desoldering the 6 pins and pulling these all at once, and risk ruining the tiny solder traces under the board, or clipping each pin from the top, and trying to remove each clipped solder pin 1 at a time. I found it impossible to do with the tight space tolerances and I discovered the solder pins on the original pot are very hardened steel. Even with my sharpest wire cutters, I only succeeded in clipping one end pin with much effort.

Here is how I solved this problem. I took the original pot apart from the top leaving only its circuit board and the 6 pins. by repeatedly and carefully flexing this very thin board, I managed to break all 6 pins free of their IC board, leaving 6 soldered in place pins protruding from the top.Now I could solder the new pot leads directly onto these remaining pins, leaving the circuit traces intact , no desoldering needed. Since the leads of the new pot were overly long when matched up against these clipped leads, I had to precisely cut each to fit over the old pins. I also had to clip the old pins a bit shorter to fit these alongside and inside the new pins. When I had a match, I now soldered the 2 anchor pins in place, to keep everything from moving as I needed to solder each pair of the 6 pins together, not easy either, I needed my smallest soldering pen to do this. Success at least from how it looked.

Put everything back together, it works perfectly, This is a stereo pot with 3 leads for each stereo side, sort of 2 pots in one. My only regret is that the new replacement is definitely not as robustly designed, the shaft is plastic and can be easily broken but the original volume knob fits and it works.

I posted this long detailed description for anyone who has one of these, the volume pots frequently go bad and after taking the original apart, I can see why. These are designed with the tiniest contact brushes-very thin metal prongs-I have ever seen. And the body of the pot wiggles loose from the IC board-there are 4 metal prongs that hold it together and once these loosen over time, now the contact brushes are not making good contact with the carbon and metal traces inside. I think I might have been able to repair the pot in place, by prying these pins tightly back in place, but I noticed the shaft also had play vertically which might have also been causing the poor and intermittent problems I was having so I opted not to try. This is a 20+ year old instrument, the miracle is that it still works at all. Some of my new modules look like they were designed for "Toys-R-Us". Not this one. Thanks for reading , if you had the patience, congratulations!

[Jesse]

No pictures

[Jokeyman123]

Here are a few, there is another website that shows pictures for disassembling the entire ION, not too difficult. soldering the voltage pot needs some skill, and the IC board needs to be removed, gave me a chance to clean the knobs and pots a bit. Notice the 6 pins are not for the volume pot, these go straight to the 3 wheels. I did not manage to take pictures underneath showing my soldering kludge. Maybe another time, as i just received a new screen from AliExpress that looks like it might be a swap for the existing which is showing its age, and wasn't great in the first place. Meanwhile my Fusions are yelling for more attention.

The Ion ribbon connector has the same number of leads and is the same style of push to mount in the IC board as this new LCD screen. Unfortunately, the new screen has a shorter ribbon cable, I will have to see if I can get this to fit. so i will probably be disassembling this again at some point, after I get through a St. Patrick's parade and 3 doctor/dentist appointments next week. and I'm retired (supposedly). A working volume pot makes all the difference in the Ion, I never got to hear how it really sounds in full stereo, why this pot is so important.

[Jokeyman123]

Here is one shot inside the faulty volume pot-I saw how easy it would be for this to fail over time-not so much from these contacts, but there are carbon traces fixed to the separate IC board, and I am guessing that these were worn, and as i originally decided, the metal case of the pot which was attached to the internal IC board had come loose over time, thus causing these delicate internal metal prongs to no longer make good contact with the carbon traces on the IC board inside. Sorry about the hairs, didn't notice until I macro'd this photo. You can see the metal prongs that were anchoring the rest of this together.

[Jesse]

Nice, Thanks I can see clearly now
Have a great day

[Jokeyman123]

Yes... can see clearly now the rain is gone. I can see all obstacles in my way. It's a bright and sunny day-but not here!
Seriously though, my only regret that for all this, i could not find the original volume pot with the more solid construction, but I didn't scour through the major electrical supply houses who usually require a large quantity order for any component like this. The other interesting (maddenng [posibly) project I am about to try-when I get some more free time probably not for at least a few days, is the new screen that just arrived from Aliexpress. I will send a picture as soon as I find it-I hide things so I will remember where they are, then I forget where I put them. Why I have large things around the house-its harder to forget where the sofa is, the stairs, etc.