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geekhack Community => Keyboards => Topic started by: _rubik on Thu, 07 December 2017, 20:56:57

Title: Ferrite Clamps/Beads?
Post by: _rubik on Thu, 07 December 2017, 20:56:57
Does anyone actually use them anymore, or have we gotten to the point where our USBs are internally shielded enough to disregard them?
Title: Re: Ferrite Clamps/Beads?
Post by: Tactile on Thu, 07 December 2017, 21:23:06
I've never added them myself. I have some keyboards which incorporate them in the cable and some not. I just plug the keyboards in & use them.
Title: Re: Ferrite Clamps/Beads?
Post by: OfTheWild on Thu, 07 December 2017, 21:47:18
I've never needed one with any modern stuff.

My IBM Model F XT however gets all screwed up if my cellphone is next to it.
Title: Re: Ferrite Clamps/Beads?
Post by: _rubik on Thu, 07 December 2017, 21:49:58
I've never needed one with any modern stuff.

My IBM Model F XT however gets all screwed up if my cellphone is next to it.

That's pretty wild. I always thought that their effect was very subtle and more theoretical than anything. I guess the interference can get pretty nasty on some older cables.
Title: Re: Ferrite Clamps/Beads?
Post by: rich1051414 on Thu, 07 December 2017, 22:15:24
My WASD Code keyboard has problems with cables not ferrite beaded, and it also freaks out when my cell phone is placed near it. The LED's will flicker, and it will randomly disconnect and reconnect. Sometimes causing it to lock up entirely. It also used to freak out by the microwave. That keyboard now has 3 beads on it so it performs normally xD

However, I think there is actually something wrong with it.
Title: Re: Ferrite Clamps/Beads?
Post by: OfTheWild on Thu, 07 December 2017, 23:41:21
I've never needed one with any modern stuff.

My IBM Model F XT however gets all screwed up if my cellphone is next to it.

That's pretty wild. I always thought that their effect was very subtle and more theoretical than anything. I guess the interference can get pretty nasty on some older cables.

I was lead to believe that it has more to do with the PCB on the internals rather than the cable? I'm not an expert in these vintage boards. 'engicoder' was explaining it to me once a while back.
Title: Re: Ferrite Clamps/Beads?
Post by: OfTheWild on Fri, 08 December 2017, 00:26:16
Found some of his info...
https://geekhack.org/index.php?topic=85979.msg2309103#msg2309103
Title: Re: Ferrite Clamps/Beads?
Post by: daskeybo on Fri, 08 December 2017, 08:51:52
My WASD Code keyboard has problems with cables not ferrite beaded, and it also freaks out when my cell phone is placed near it. The LED's will flicker, and it will randomly disconnect and reconnect. Sometimes causing it to lock up entirely. It also used to freak out by the microwave. That keyboard now has 3 beads on it so it performs normally xD

However, I think there is actually something wrong with it.

Microwave susceptible?  That seems like a FCC issue.
Title: Re: Ferrite Clamps/Beads?
Post by: ddot on Fri, 08 December 2017, 10:16:25
I was getting some weird behavior on one of my boards, so I tried picking up a set of ferrite cores similar to this:

https://www.ebay.com/itm/5-Pcs-Black-UF-50B-Clip-On-Noise-Suppressor-5mm-Cable-New-Ferrite-Core-Filters/232194518755

It tuned out to be a firmware issue on the board, so the ferrite cores weren't the solution.  Since then I've played around with the cores for fun, but so far haven't noticed a difference on anything one way or the other.

Side note, I've slowly been realizing over the years how the quality of USB cables can differ.  A decent quality cable is always a good place to start.  I stumbled across these ones:

https://www.ebay.com/itm/1m-Braided-Micro-USB-Sync-Data-Fast-Charging-Cable-Charger-For-Android-Phone-CA/301966509428

Despite being "Made in China" and cheap price wise, I've found them to be very good quality.  I had one old phone that was very picky about what cables you could use to connect it to a computer.  For a while, only the OEM cable that came with it would work.  Now it's the OEM cable and the above mentioned ones.
Title: Re: Ferrite Clamps/Beads?
Post by: _rubik on Fri, 08 December 2017, 18:55:05
I pulled apart my rf87u today and realized that they actually both ground the cable and have a ferrite clamp inside the case. I'm assuming that most boards that have an attached cable have an internal bead, because why not?
Title: Re: Ferrite Clamps/Beads?
Post by: rich1051414 on Fri, 08 December 2017, 21:44:54
My WASD Code keyboard has problems with cables not ferrite beaded, and it also freaks out when my cell phone is placed near it. The LED's will flicker, and it will randomly disconnect and reconnect. Sometimes causing it to lock up entirely. It also used to freak out by the microwave. That keyboard now has 3 beads on it so it performs normally xD

However, I think there is actually something wrong with it.

Microwave susceptible?  That seems like a FCC issue.
The microwave that caused it did die, and the new one does not cause it, so it probably was, however, the keyboard should not be that sensitive to RF. It seems to only be susceptible to RF on the ground shielding of USB cables, which still should not happen. There is obviously something wrong with the keyboard to cause it to be so sensitive, but I have NO IDEA what it could be.

It took me a very long time to figure out what the problem with it was, and I am still baffled that a heavily choked USB cable fixes it. What could cause that? Oh and it still doesn't like going through a USB Hub either, I have to plug it directly into the back of the PC, even the front IO header causes it problems. It is so sensitive to noise...

I have owned it passed its warranty, so its not going to be RMA'ed, so unless I figure out what is causing the issues, I might just have to desolder the board for the cherry mx clear switches. However, for now, as long as I use it plugged into the back of the PC, and use a cable that has been beaded 3 times, the keyboard works fine without weird behavior, as long as I keep my cellphone away from it.

The only thing I can think of is that there is a cold joint somewhere that happens to be the ideal gap size to pick up RF interference, but I am only guessing here. I could not spot any cold joints on the board at all.
Title: Re: Ferrite Clamps/Beads?
Post by: SamirD on Sun, 10 December 2017, 01:40:07
Even though it's outside of warranty, I'd call them and ask their opinion on it.  After all, they made it and I'm sure they'd be interested in this weird behavior you've discovered.  It may happen across that model and you're the first to really bring it to light.
Title: Re: Ferrite Clamps/Beads?
Post by: Magnoliya on Wed, 02 June 2021, 06:48:17
Nah, there are many other beds that I would rather use instead. Don’t get me wrong about this. All keyboards are like toggle clamps to me. If there is anyone that doesn’t know what a toggle clamp is on here you go https://www.sandfieldengineering.com/toggle-clamps/ In general I’m looking forward until the keyboards will become a hologram that will be responding to our touch. Even though this seems to be like far in the future, I hope that I will still get to live in those days. Is there anyone who agrees with me?