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I am looking for replacement rotary encoders for my Yamaha A4000 sampler. These samplers have a common problem where the encoders start to work poorly after time. It is Yamaha part number V4441800, which is Alps Alpine part number EC11B1524209, according to the service manual.

I found some info about the Alps EC11B series https://www.farnell.com/datasheets/1837001.pdf

This is the service manual: https://www.mediafire.com/?judihzdj4jt

Places like Mouser sell EC11B series encoders with no minimum order required, for about 5 USD/piece, but I don't know what to look for, to be able to find a suitable replacement. I just need a part that will let me select and scroll through menus, enter data, move values up/down, etc, on the sampler.

I understand I need a 11mm size horizontal-type encoder with a momentary push-on switch, with a shaft that won't be too short. Does the number of detents, pulses, or resolution matter? Does the brand matter? Is the pinout the same/universal on all encoders? If I choose the wrong encoder, can I damage the sampler? What else do I look for?

Edit: I measured about 0.5mm of push-in travel

Edit: Here are some pictures, please let me know if they don't work:

https://u.cubeupload.com/MH1234/20210819171826.jpg

https://u.cubeupload.com/MH1234/20210819172937.jpg

https://u.cubeupload.com/MH1234/20210819173226.jpg

https://u.cubeupload.com/MH1234/20210819172113.jpg

https://u.cubeupload.com/MH1234/20210819172350.jpg

https://u.cubeupload.com/MH1234/20210819172416.jpg

Thanks

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    \$\begingroup\$ Did you try cleaning it with contact cleaning spray? See the disassembled unit in my answer to this. \$\endgroup\$
    – Transistor
    Aug 19 at 20:40
  • \$\begingroup\$ please do not crosspost ... forum.allaboutcircuits.com/threads/… \$\endgroup\$
    – jsotola
    Aug 19 at 20:41
  • \$\begingroup\$ you could replace it with 3 spst momentary buttons (1 to click, 2 to scroll), if that helps conceptualize it for you. you won't break anything with a mismatch (the pins are supposed to be sometimes shorted together), but the feel could be off or it could just not work reliably, skipping and missing clicks. \$\endgroup\$
    – dandavis
    Aug 19 at 20:47
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    \$\begingroup\$ I have not yet tried contact cleaning spray, as the purchase cost is similar to the cost of new encoders. What % chance could I have of being able to fix skipping or erratic encoders with contact cleaner? \$\endgroup\$
    – MH1234
    Aug 19 at 23:25
  • \$\begingroup\$ I give Transistor's suggestion better than a 90% chance of working. \$\endgroup\$
    – Gil
    Aug 20 at 0:35
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Some of them use hall sensors, and some use switches. The resolution means that you will have to make more turns if you chose the one with lower resolution. The number of detents makes the different feel, but electrically has no meaning. The same footprint comes also for Bourns (I don't remember exact model)

You have to measure (or find the datasheet of EC11B1524209) shaft diameter, shaft type, shaft length, overall length, pin arrangement, ...

EDIT:

Bourns PECR11

EDIT2:

Try EC11B15242AE, it seems the same, check.

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  • \$\begingroup\$ I added photos with measurements made with a ruler, in my original post \$\endgroup\$
    – MH1234
    Aug 19 at 23:27
  • \$\begingroup\$ @MH1234 There is no much you can choose: EC11B15242AE (0.5mm travel) or EC11B15242AF (1.5mm travel). Drawing No. 2 or 3. \$\endgroup\$ Aug 20 at 8:58
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These are mechanical contacts and are rated for 25k operations and need 5mA minimum current where Rmin goes from 100 to 200 mohm from your Alps’ spec.

I would suggest cleaning with electronic spray cleaners while rotating then put caps across the contacts to centre to increase the wetting current. The ESR of the caps will limit the energy of the tiny arc. It will also reduce contact electrical bounce. Value TBD. From past experience I used 10uF tantalum without cleaning and then it self cleaned and all started working. Too big a C will cause pitting in the-wiper.

However chatter time is 2 to 3 ms and this increases, could cause issues. This suggests if the design uses 1k pullups to 5V to achieve the minimum wetting current, for RC=3ms C must be around C=3ms/1k = 3uF so try 3 to 5 uF.

E.g. SMT Tantalum 5 ohm 3.3 uF

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You can try replacing it with the easily available ones. The number of detents should be roughly similar.

It could work okay, or you could have issues such as working backwards (swap A and B pin connections) or it might not work reliably due to the debouncing algorithm used or the way the contacts make/break (no easy solution).

I think your odds are fairly good.

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Based on responses here, I decided to order a can of Deoxit D5S-6, since my chances of success seem high. I will try to spray the shaft and housing, so the liquid works itself into the encoders, and I will see what will happen.

If Deoxit doesn't help, I will order either EC11B15242AE or EC11B15242AF encoders, depending on whichever one is the easiest to get. On the 1.5mm travel version, I might need to add shims or a spacer to the shaft end or to the inside of the plastic knob, if the plastic knob will be bumping into the front panel of the sampler, when pushed in. I will avoid adding capacitors unless I really have to, as I don't have any experience modifying circuits.

Thanks

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  • \$\begingroup\$ The switches wear out, so using a contact spray can help just for few time. In the datasheet it says 15k cycles and it doesn't mention that you'll get another 15k cycles if you spray something. \$\endgroup\$ Aug 20 at 21:33
  • \$\begingroup\$ The Deoxit will arrive next week. Once I try cleaning them, I will find out if the encoders were only dirty and oxidised, or if they are worn out and need to be replaced. I am not the original owner, so I don't know the history of the sampler. It is possible they could only have 1,000 cycles on them, as the sampler is in excellent cosmetic condition. Although the unit looks nearly new, some metal parts have signs of being in a humid enviornment, and the contacts in the in/out jacks are dull/discolored, and there is static if you wiggle the audio cables when plugged into the jacks. \$\endgroup\$
    – MH1234
    Aug 21 at 0:30
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I got the deoxit spray yesterday, and I sprayed all the encoders. I sprayed the encoder housing so the deoxit would work itself inside, and also sprayed the place where the shaft goes into the encoder housing, and operated the encoders. I did fast turns, and also turned them click by click to attempt to clean them. I repeated this 3-5 times. It seems to have made not much of a difference. They still don't work correctly sometimes. The most frequently used encoders work the worst, in general. I think they are worn out.

I used deoxit on the master and rec volume pots, and those pots seem to turn more easily. I also used deoxit on the contacts inside each audio jack. I noticed the audio crackle I used to sometimes get is not present anymore, even if I wiggle plugs inserted into them.

I will be ordering Alps EC11B15242AF (1.5mm travel), as that is what is easily available where I live. If the push-in travel will cause the knobs to bump into the front face, then I will put something in between the encoder shaft and knob, to create a bigger space between the knob and front face.

Because I don't own a temperature controlled soldering station, I will be installing them with a regular soldering iron that I used before on other electronics. I don't think the new encoders will be that picky on soldering temperature, if I only apply heat for less than 3 seconds on each pin.

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I installed the EC11B15242AF encoders, and they work perfectly. I used a regular soldering iron for electronics. I tightened the encoders to a flat and straight piece of metal, to keep the encoders lined up when soldering. I needed to add spacers to the ends of the shafts (to make the shafts longer by about 1mm), so that the push switch function would work correctly when fully assembled.

Thanks to everyone for your help.

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