PCB works on newer PCs, not on older ones. Where could be the issue?

[Eszett]

Hi! A friend of mine experiences a quite odd problem, his custom built PCB works perfect on newer PCs (Win or Linux, doesn't matter).
However, with older ones he has the following issues:

- quote: there is a lot of chatter, random keys, random times.

- quote: when you first plug it in you have to press a bunch of keys before it starts typing.

Can that be design flaw of the PCB, and how and why? I can show the schematics if needed. AFAIK key chatter is something that is caused either by bad soldering, or by bad configuration of the firmware. But how can it be dependant on different PCs? I don't understand that...

[nubbinator]

Probably a BIOS/UEFI setting, firmware issue, polling rate issue, etc.

[Eszett]

Hi nubbi! Yes, but how does that explain different results on different PCs? He states, that on newer PCs the PCB works literally *perfect*.

[bmmcwhirt]

NKRO will not work on many old computers and on lots of apple computers. So start by disabling NKRO to see if that corrects the problem.

[dgneo]

Hi nubbi! Yes, but how does that explain different results on different PCs? He states, that on newer PCs the PCB works literally *perfect*.

How old is old? Different operating systems? What connection type is the keyboard using?

[smokemm]

Hey,

The friend here chiming in.
Thanks Eszett for posting on my behalf

dgneo:
- Out of the two older pcs that I tested the keyboard on there was a Lenovo x1 carbon laptop.. probably from 2012, and my desktop which is roughly 3 years old.
- Laptop was running Ubuntu 16.10 and the desktop Windows 10.
- Mini USB to USB type A

bmmcwhirt: I will give that a shot and report back