deskthority

Hi,
So in the past month I bought a KBD75 kit and put it together and everything has been totally swell up until pretty recently.

Starting the other day, I started shocking or getting shocked (static discharge) by the keyboard much more frequently than usual. Everytime I did this it would power down the keyboard, and I'd have to unplug it and plug it back into the computer.

Now, I'm not positive that this was caused by the shocks, but somewhere in there all but one of the RGB LEDs on the bottom of the board stopped working.

So, currently, when the keyboard is plugged in, only the LED in the upper right corner, nearest the USB plug, turns on. The rest are out. I tested each of the LEDs by applying power to them individually, and they all turn on, so it does not appear that the problem is caused by a burnt out LED.

But that's about the limit of what I have to try. I don't know what the next steps are, and I, to be totally honest, simply don't know what to do.

So I could really use some help. Thank you.

For reference, here is a photo of the PCB: https://imgur.com/a/RC8HZ

Oh also for reference, I have

- An oscilloscope
- A voltmeter
- Full soldering suite
- New me9926 LED mosfet driver SMD thingy
- New WS2812b RGB LED modules.

Nobody? Nobody has any ideas?

I had a similar issue with my Leeku L3 1800.
The issue was generated by a RGB LED dying out.

This was my solution and it might work for you too:
Because the RGB LEDs are connected in series, if one has issues, then all of the rest after it look like they are dying.

So, set your PCB to light the RGB LEDs in a snake patern (RGB1 -> RGB2 -> RGB3 -> etc) and look at each one very very carefully. The first one you see acting up (even if it is just a small stutter) should be changed because the issue is amplified from one another as they are mounted in series.

I also changed the RGB controller, even though I do not think it was necessary.

Here is the thread I opened with my RGB issues: workshop-f7/lighting-issues-with-leeku- ... 17187.html

So I started checking things with an oscilloscope.

- All the LEDs have 5V in, i.e. they are all powered, presumably.

- The working LED has a good input (DIN) and output (DOUT). No surprise there.

- The LED to the right of it (see picture) has a good signal in, but nothing on the output terminal.

- All other LEDs have neither an input nor output signal

- I thought maybe that LED right next to the working one is the problem, but jumping over it doesn't fix anything. I.e., jumping the DOUT on the good LED to the DIN on any LED other than that right next to it (the one with the good DIN) doesn't turn them on.

- ????

Diagram: https://imgur.com/a/WSHwf

You know what, I think that LED must be dead. For whatever reason, jumping DOUT of the working LED to DIN on any other doesn't do anything, BUT, jumping the signal coming out of either of those resistors right next to the working LED to the DIN of any other LED sure works. Take a wild guess which LED it fails to turn on...

Why that path works and DIN to DOUT doesn't is beyond me, though....

Just get a bunch of replacement RGB leds .. they are really cheap, their product code should be something like WS12...

then replace the first non-working RGB in the circle. stop wasting your time measuring stuff no one here really has a clue about. This happens all the time and derzemel pretty much explained it well.

Wodan wrote: stuff no one here really has a clue about.

This is really what blows my mind the most. Don't some of you guys, like, design PCBs? I'm surprised that a group of people who spend their time not just building custom keyboards from the ground up, but sometimes outright designing them, don't have much to say when it comes to debugging electronics.

Anyway I'm 90% sure I've identified the problem LED. I haven't replaced it but I will today. I do still appreciate all the help.

PS they are WS8212b SMD RGB LED modules. Fortunately, I have some on hand that I bought when I had to replace an LED on a different keyboard of mine.

I am more concerned with the fact that you noticed the problem as you where "getting shocked more than usual".

I think its a problem if you get socked AT ALL by a keyboard.

Most of the designers are actually on Geekhack. DT tends towards the old, GH towards the new, and Reddit, well... whatever a meme would look like in real life is the content there. That's not to say that we don't have people with electrical engineering experience here, but it's not as common as you might think. I am extremely good with a soldering iron and debugging basic issues but that doesn't make me a designer.

Blaise170 wrote: Most of the designers are actually on Geekhack. DT tends towards the old, GH towards the new, and Reddit, well... whatever a meme would look like in real life is the content there. That's not to say that we don't have people with electrical engineering experience here, but it's not as common as you might think. I am extremely good with a soldering iron and debugging basic issues but that doesn't make me a designer.

I asked this question on geekhack too (and reddit). Neither place was tremendously useful.

Most of what I get is like "CHECK TRACES YOU NEED TO CHECK TRACES" and then I'm like "There are a MILLION fucking traces can you give me a reference point or something? I'm not even sure what I'm looking for." and then no further responses.

andrewjoy wrote: I am more concerned with the fact that you noticed the problem as you where "getting shocked more than usual".

I think its a problem if you get socked AT ALL by a keyboard.

This has a fairly simple solution. And getting shocked by a giant hunk of metal is not really that surprising. Also it's probably you shocking it, not he other way around.

Success! KBD75 is fixed, replacing the dead LED fixed it. No surprise. Damn I fuckin love this keyboard.

Blaise170 wrote: Most of the designers are actually on Geekhack. DT tends towards the old, GH towards the new, and Reddit, well... whatever a meme would look like in real life is the content there. That's not to say that we don't have people with electrical engineering experience here, but it's not as common as you might think. I am extremely good with a soldering iron and debugging basic issues but that doesn't make me a designer.

Precisely. And the PCB designers around here would probably not care about RGB underglow much


Congrats on getting it fixed, too

Wodan wrote:

Blaise170 wrote: Most of the designers are actually on Geekhack. DT tends towards the old, GH towards the new, and Reddit, well... whatever a meme would look like in real life is the content there. That's not to say that we don't have people with electrical engineering experience here, but it's not as common as you might think. I am extremely good with a soldering iron and debugging basic issues but that doesn't make me a designer.

Precisely. And the PCB designers around here would probably not care about RGB underglow much


Congrats on getting it fixed, too

Oh I could give a shit about RGB bullshit, it would just drive me nuts knowing that my keyboard wasn't in perfect working order. Actually, after this whole ordeal, I'm seriously considering getting a brass spacer cut to replace the polycarbonate one that the LEDs shine through.

PancakeMSTR wrote:

Wodan wrote:

Blaise170 wrote: Most of the designers are actually on Geekhack. DT tends towards the old, GH towards the new, and Reddit, well... whatever a meme would look like in real life is the content there. That's not to say that we don't have people with electrical engineering experience here, but it's not as common as you might think. I am extremely good with a soldering iron and debugging basic issues but that doesn't make me a designer.

Precisely. And the PCB designers around here would probably not care about RGB underglow much


Congrats on getting it fixed, too

Oh I could give a shit about RGB bullshit, it would just drive me nuts knowing that my keyboard wasn't in perfect working order. Actually, after this whole ordeal, I'm seriously considering getting a brass spacer cut to replace the polycarbonate one that the LEDs shine through.

And if you hadn't noticed, DT is a lower traffic site, with people not visiting everyday and posting everything that comes to mind as on GH and reddit. It's sad at times when you want feedback, but true. Many of the OGs don't visit very often at all for one reason or the other.

Patience is the key if you want help here, IMO.

chuckdee wrote: And if you hadn't noticed, DT is a lower traffic site, with people not visiting everyday and posting everything that comes to mind as on GH and reddit. It's sad at times when you want feedback, but true. Many of the OGs don't visit very often at all for one reason or the other.

Patience is the key if you want help here, IMO.

Yeah I know. Whenever I'm posting here it's typically as a last resort, no offense.

PancakeMSTR wrote:

chuckdee wrote: And if you hadn't noticed, DT is a lower traffic site, with people not visiting everyday and posting everything that comes to mind as on GH and reddit. It's sad at times when you want feedback, but true. Many of the OGs don't visit very often at all for one reason or the other.

Patience is the key if you want help here, IMO.

Yeah I know. Whenever I'm posting here it's typically as a last resort, no offense.

None taken (at least by me), and I have the same outlook for certain things. The audiences are just different, and interested in different things, IMO.