Saturday, June 06, 2015

Fixing Double or Repeated Characters on Dell Laptop Keyboard

I was having a major issue with my new Dell Precision M4800 laptop that I got in 2015. I would frequently get repeated keys, especially the space bar. For example, after typping a typpical  senntence it  would look  something  like  this. I had to go back and touch up multiple items in every sentence after typing it.

This is what I did to fix the problem:
1. Go to Control Panel / Ease of Access Center and turn on FilterKeys
2. Select BounceKeys radio option and 2.0
3. Go to regedit
4. Navigate to HKEY_CURRENT_USER\Control Panel\Accessibility\Keyboard Response
5. Enter the following values:
  • autorepeatdelay:500
  • autorepeatrate:50
  • bouncetime:40
  • delaybeforeacceptance:0
  • flags:59
It is still happening some, but is a lot better (about 98% fixed). I may tweak the settings further to try to improve it even more.

The key setting is the bouncetime. When you type a key, it is making a connection that sends a signal. Sometimes the laptop will detect two signals on the same keystroke. Why? The bouncetime says to wait at least a certain time before recording a second keystroke. For example, say you press space bar and there is a period of 15 milliseconds where the receiver continuously senses the space bar signal coming through (for whatever reason). If the bounce rate was set to "14", it would detect the inital space bar at time 0 ms and then a second one at time 14 ms. By increasing the bouncetime to 40, only one space bar would be registered in this case. The signal would have to last for 40 ms before two keystrokes would be registered. The only downside is that if you are super fast and press a key twice in less than 40 ms, then it will only be counted once. I tried to do this and am unable to press a key twice within 40 ms, so this seems like the right setting for me. By the way, I just typed this entire paragraph without any repeated characters - and you have no idea how much better that is than it was before!


At 6:01 AM, Blogger Chromis said...

I have the same problem with my M4800. I even replaced the keyboard, but to no avail. I just tried your regedit settings, and it seems to be fixed, as I am typing this. THANK YOU. I was ready to attribute this to a faulty motherboard or keyboard ribbon. THANK YOU.

At 6:02 AM, Blogger Chromis said...

And for the record: I KNOW exactly how much better it is than it was before! i was in repeat key hell! Thank you.


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