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geekhack Community => Keyboards => Topic started by: bmilcs on Sat, 05 March 2016, 12:31:25

Title: Fixing Pok3r LED after desoldering
Post by: bmilcs on Sat, 05 March 2016, 12:31:25: Hey folks,

I desoldered the ONE LED I need to work on my Pok3r keyboard... the one that indicates programming mode and flashes when you're actually programming a key. I removed it in order to modify my spacebar and it's sliders which came out beautifully. Even the LED that connects to the space bar MX switch itself is fine.

However, I cannot get the one directly on the PCB board to light up anymore. I don't recall specifically but I believe it was just a standard blue LED.

What do you think would cause this? I made sure the +/- are correctly aligned... which was easy. They left one leg longer than the other and made sure to reinsert it the same way. Sadly, it won't show any signs of life.

I'm relatively new to soldering... having only done 1 keyboard worth of MX switches. I do not own a multimeter but I think it may be time to take the plunge.

Any tips are welcome :D
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Sat, 05 March 2016, 12:37:10: Just a quick note: I am using the ST7 Weller tip... the super fine point one. It works just fine. However, desoldering these super tiny LED points is very difficult. I'm at a loss.

Do LED's break easily? Could it simply be the light itself?
Title: Re: Fixing Pok3r LED after desoldering
Post by: xtrafrood on Sat, 05 March 2016, 13:30:56: You may have overheated that LED. I'm not an expert but if it worked before you desoldered, and you installed it back the way it was, overheating could be the issue. From my understanding LEDs are like other manufactured goods in which sometimes you'll get a bad one.

Seems kind of odd that would be the issue though, maybe someone will know what is going on.
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Sat, 05 March 2016, 18:02:36: Quote from: csmertx on Sat, 05 March 2016, 13:30:56
You may have overheated that LED. I'm not an expert but if it worked before you desoldered, and you installed it back the way it was, overheating could be the issue. From my understanding LEDs are like other manufactured goods in which sometimes you'll get a bad one.

Seems kind of odd that would be the issue though, maybe someone will know what is going on.

Yeah I'm really unsure at this point. I did notice that it wasn't installed flush and I mimicked it's initial setup. The right post was inserted fully into the PCB and the left was not. That is how I knew which way to insert it back. I really hope I didn't ruin the PCB, as I had to solder/de-solder it a few times trying to get it to work. I didn't keep it heated for longer than 2-3 seconds tops though and never back to back... without a pause in between.

I lack the experience and knowledge to comfortably diagnose the issue. I should take pictures and post them... but that requires finishing my fresh format and re-installation of Windows 7. Windows 10 back to 7 was not nearly as seamless and error-proof as the upgrade was lol. It destroyed my task scheduler and noticed a few other bugs so I decided to give my new PC a fresh install.
Title: Re: Fixing Pok3r LED after desoldering
Post by: xtrafrood on Sat, 05 March 2016, 18:13:17: I'm guessing the LED changes colors as you switch between the different layers? Dual? RGB? Does anyone know what is in the new Pok3r boards?
Title: Re: Fixing Pok3r LED after desoldering
Post by: iaeen on Sat, 05 March 2016, 18:38:20: I'd de-solder the LED again and do something like this: http://www.instructables.com/id/Testing-LEDs-with-a-Multimeter/. That will tell you if it's the LED or something going on with your board.
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Sun, 06 March 2016, 15:26:02: Arg. It's a mess now. Such a bugger of a solder point. I got it out completely and noticed it was messy. Tried wiping it off with paper towel and isopropyl and now it looks way worse.

(https://farm2.staticflickr.com/1635/25271136780_367df101dc_k.jpg) (https://flic.kr/p/Ev8bwQ)DSC_9113.jpg (https://flic.kr/p/Ev8bwQ) by bmilcs (https://www.flickr.com/photos/52658307@N03/), on Flickr

Did I completely butcher the board??? I notice the metal that sits on the face of the board came peeling upward.
Title: Re: Fixing Pok3r LED after desoldering
Post by: xtrafrood on Sun, 06 March 2016, 15:41:00: All that extra curricular keyboard activity on your flickr account indicates to me that you would have a multimeter, or at the very least can borrow one from a friend or colleague ;). Check out that diode, the LED etc and see where the problem is.

However, if the keyboard is fully functional aside from that LED I would say let it chill. Maybe in the future you'll talk to someone that can identify the exact problem you're having.
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Sun, 06 March 2016, 15:53:08: Quote from: csmertx on Sun, 06 March 2016, 15:41:00
All that extra curricular keyboard activity on your flickr account indicates to me that you would have a multimeter, or at the very least can borrow one from a friend or colleague ;). Check out that diode, the LED etc and see where the problem is.

However, if the keyboard is fully functional aside from that LED I would say let it chill. Maybe in the future you'll talk to someone that can identify the exact problem you're having.

Like soldering, I always wanted one but owned one.

I was planning on getting a Craftsman cheapy. Essentially, all I want to do is find out if there is power going through a source yes? I typically don't need exact measurements.
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Mon, 07 March 2016, 15:20:09: How do you suggest that I clean the area properly?

So the term is called DIODE for the hole there?
Title: Re: Fixing Pok3r LED after desoldering
Post by: Badwrench on Mon, 07 March 2016, 15:31:05: Quote from: bmilcs on Mon, 07 March 2016, 15:20:09
How do you suggest that I clean the area properly?

So the term is called DIODE for the hole there?

To clean this up, use some Isoproply on a Q-tip and really work it around there. Most of that should come clean. Unfortunately, it looks like you cook the pads right out of it. I can see one trace still visible (on the left), but the right one is either covered or pulled clean.

As far as repairing, you will need the multimeter in continuity mode, with the board unplugged, and find where the trace for the right hole goes. The one on the left goes to that resistor just to the right of it (check with mulitmeter to confirm though).

This is how it looks to me:
[attach=1]
Title: Re: Fixing Pok3r LED after desoldering
Post by: suicidal_orange on Mon, 07 March 2016, 15:46:26: The Pok3r LED circuit is weird, I asked about it here (https://geekhack.org/index.php?topic=79436.msg2044785#msg2044785) and there were a couple of ideas but nothing definite. You can see in the pic in that thread all the LEDs connect to the LR## (resistors?) on both sides, and the + legs are all connected in columns.

I don't see a + but perhaps you remember where it was? Hopefully it's the pad furthest away in your pic, in which case you just need to find which column it should be in...
Title: Re: Fixing Pok3r LED after desoldering
Post by: xtrafrood on Mon, 07 March 2016, 15:49:58: Quote from: Badwrench on Mon, 07 March 2016, 15:31:05
Quote from: bmilcs on Mon, 07 March 2016, 15:20:09
How do you suggest that I clean the area properly?

So the term is called DIODE for the hole there?

To clean this up, use some Isoproply on a Q-tip and really work it around there. Most of that should come clean. Unfortunately, it looks like you cook the pads right out of it. I can see one trace still visible (on the left), but the right one is either covered or pulled clean.

As far as repairing, you will need the multimeter in continuity mode, with the board unplugged, and find where the trace for the right hole goes. The one on the left goes to that resistor just to the right of it (check with mulitmeter to confirm though).

This is how it looks to me:
(Attachment Link)
Thank you for the correction. :)
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Mon, 07 March 2016, 16:07:07: Okay. Once I find out where it leads, I solder a jumper wire between the two? Directly into that little metal/black piece that sticks up?
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Mon, 07 March 2016, 16:36:40: Ah man it's worse than I thought.

(https://farm2.staticflickr.com/1697/24967488004_169eae47f6_o.jpg) (https://flic.kr/p/E3hUk7)DSC_9119.jpg (https://flic.kr/p/E3hUk7) by bmilcs (https://www.flickr.com/photos/52658307@N03/), on Flickr

Here's the other side for reference. Clearly, I messed up this pad as well -_-. What am I doing wrong? Heating it for too long?

(https://farm2.staticflickr.com/1481/25505281131_b9ea2fa89f_o.jpg) (https://flic.kr/p/ERPeup)DSC_9125.jpg (https://flic.kr/p/ERPeup) by bmilcs (https://www.flickr.com/photos/52658307@N03/), on Flickr
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Mon, 07 March 2016, 16:37:33: It looks like I ripped up the entire trace that lead to the top portion of that metal diode or what have you. It's SO small that I couldn't tell until this photo. I'm going to have to get a magnifying glass setup.

So, all hope is not lost?
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Mon, 07 March 2016, 16:44:53: Weller WLC100 40-Watt Soldering Station. At max, it's 40 watts and I usually use setting 2/5.
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Wed, 09 March 2016, 15:04:24: Quote from: Badwrench on Mon, 07 March 2016, 15:31:05
Quote from: bmilcs on Mon, 07 March 2016, 15:20:09
How do you suggest that I clean the area properly?

So the term is called DIODE for the hole there?

To clean this up, use some Isoproply on a Q-tip and really work it around there. Most of that should come clean. Unfortunately, it looks like you cook the pads right out of it. I can see one trace still visible (on the left), but the right one is either covered or pulled clean.

As far as repairing, you will need the multimeter in continuity mode, with the board unplugged, and find where the trace for the right hole goes. The one on the left goes to that resistor just to the right of it (check with mulitmeter to confirm though).

This is how it looks to me:
(Attachment Link)

Bizarre. Apparently that through-hole goes to the POS post of the standard space bar led. Does this make sense?

Both LED's in question light up in continuity mode. My KUL LED does not. Why do neither beep indicating less than 30 ohms?
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Wed, 09 March 2016, 16:41:57: (https://farm2.staticflickr.com/1541/25286976469_b7073beb75_o.jpg) (https://flic.kr/p/Ewwn7V)DSC_9132-Edit.jpg (https://flic.kr/p/Ewwn7V) by bmilcs (https://www.flickr.com/photos/52658307@N03/), on Flickr

Does this make sense? I don't see how the trace could've ended up here. Edit* It also shows a connection to the diode to the right of the space bar LED.

Also, do you have any tips for soldering the wire to these points? I'm still very new. I don't want to ruin that diode.
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Wed, 09 March 2016, 16:58:20: Sorry the 100 questions but google is getting me nowhere.

How do I determine the polarity of these multicolor LEDS? If I swap the positive/negative terminals, they light up blue or red. The PCB isn't labeled either. Is there a way to determine which is which?
Title: Re: Fixing Pok3r LED after desoldering
Post by: bmilcs on Thu, 10 March 2016, 17:16:29: OH HAPPY DAY <3

Sorry everyone for having to endure my 1000 questions. I beat things to death and make them over complicated.

Thank you all for your help! And, win win. I removed the static LED on the left that changes color regardless if LED's are on to indicate what layer you're on :D

(https://farm2.staticflickr.com/1571/25684026495_6e7d0c2302_o.jpg)

(https://farm2.staticflickr.com/1491/25057288033_67718080cd_o.jpg)
Title: Re: Fixing Pok3r LED after desoldering
Post by: xtrafrood on Thu, 10 March 2016, 17:20:57: Quote from: bmilcs on Thu, 10 March 2016, 17:16:29
OH HAPPY DAY <3

Sorry everyone for having to endure my 1000 questions. I beat things to death and make them over complicated.

Thank you all for your help! And, win win. I removed the static LED on the left that changes color regardless if LED's are on to indicate what layer you're on :D

Show Image
(https://farm2.staticflickr.com/1571/25684026495_6e7d0c2302_o.jpg)

Show Image
(https://farm2.staticflickr.com/1491/25057288033_67718080cd_o.jpg)

:thumb: