Seized pot shafts on a pedal

[zentropa]

I received my DOD DFX94 digital sampler / delay that I bought on ebay today and the 6-way mode knob is stuck in the trigger position, rendering the pedal useless. Im not sure if it is the wiper or shaft that is stuck.

I got the bulk of it refunded and have decided to try to get it working again. Deoxit has not helped it.

Does anyone have any tricks that I should try?

[bigtone23]

I have three ways to loosen pot shafts. In order of safety/success...
1. Naphtha. Just a drop or three down the shaft where it meets the pot body. The grain of salt is that this is a home run to match the friction of stiffer Alpha pots to the looser feel of Bournes or CTS. However, it may work to some degree with a seized pot shaft.
2. Pull the pot apart (if possible), clean and lube, reassemble.
3. Tri-Flow. It's kind of pseudo WD40 with improved teflon lubricants. My rancher uncle turned me on to it 30 years ago. Like WD40, you don't want it in the pot, but it probably will loosen the shaft. It's freed up some nasty stuck bridge screws and the like for me.

[zentropa]

Thanks.

Unfortunately these pots don't have quite the same construction of say a volume pot on a guitar, so it isn't clear where it would penetrate into the shaft with how they fit together. It is also a big pain to remove the pot. I'm worried about ruining the pot entirely since I can't source a replacement. I was planning on selling it for parts/repair and I also don't want to pass it on with something I have ruined beyond repair. I used to use tri-flow when I was restoring original Floyd Rose trems, but I ran out of it and haven't restocked.

[Pepe]

It is also a big pain to remove the pot.

If your unit looks the same inside as this one, I don't know why there is a problem to desolder it:



Also, opening these Alpha potentiometers is fairly easy. You should only be careful with the detents for the six modes.

If the potentiometer is broken and I were you I would try to find a fitting potentiometer with the correct resistance value and the correct shaft for the knob. It will be tough to find one with six detents that are in the same positions, so I would look out for one with eleven detents, open it up and remove the ones that aren't necessary (if that works).

[zentropa]

If your unit looks the same inside as this one, I don't know why there is a problem to desolder it:

I'm not really confident in my soldering ability to removing a board-mounted pot as I have never done it before. I have read that solder needs to hit both sides of the board or something like that? Is there any trick for that?

I have another DFX94 on the way, so I may give something a go, but I'm not sure if I want to make the effort or give up on it. I have found overall it is very difficult for me to source pots for older DOD pedals.

I still remember my first foray into working on pedals. I did it while on the phone with Laurie actually, replacing a blown diode in an MIJ DS-1 ~15 years ago.

[laurie]

If your unit looks the same inside as this one, I don't know why there is a problem to desolder it:

I'm not really confident in my soldering ability to removing a board-mounted pot as I have never done it before. I have read that solder needs to hit both sides of the board or something like that? Is there any trick for that?

I have another DFX94 on the way, so I may give something a go, but I'm not sure if I want to make the effort or give up on it. I have found overall it is very difficult for me to source pots for older DOD pedals.

I still remember my first foray into working on pedals. I did it while on the phone with Laurie actually, replacing a blown diode in an MIJ DS-1 ~15 years ago.

Pull the board and mail it to me (don't need the whole pedal). I can fix it for you.

[bigtone23]

Pull the board and mail it to me (don't need the whole pedal). I can fix it for you.

That.Is.the.call.of.the.master!

[zentropa]

Pull the board and mail it to me (don't need the whole pedal). I can fix it for you.

Thank you. Will send a PM

[laurie]

The DFX94 is on vacation here in Canada.

The pot shaft was completely seized in the bushing. I’m not sure whether it was old grease, or the metals bonding, but clearly the knob had been left in that position for years. Would Not Move.

Applied some careful heat and that allowed it to start moving. A bit of exercising plus potentiometer lubricant and it is spinning freely again. I'm leaving it to soak in lube overnight before reassembly and testing.
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DFX pot.jpg (240.58 KiB) Viewed 7607 times

[Pepe]

Ah, that sounds promising! Using heat is a good trick that I hadn't thought of.