Author Topic: Quickfire Rapid PCB Repair  (Read 892 times)

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Offline phoible

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Quickfire Rapid PCB Repair
« on: Sat, 05 September 2020, 14:04:52 »
I decided to replace the switches on my QFR, pretty much just for the heck of it. I got through pretty quickly, but when I finished, the Apps (Menu) key doesn't work. This isn't a big deal (since I don't ever use that key), but I'm a bit OCD about that kind of thing, so I decided to try to repair it.

Turns out that it isn't the switch, and it doesn't appear that the pad is lifted (plus I tried connecting the alternative set of pads for that switch as well as the diode leads). I figure that I can use a jumper wire, but I'm not seeing anything on the PCB that looks obviously wrong. and I'm having trouble following the schematics, particularly the diodes, but the traces snake all over the place so I might be missing something. I should have taken a picture of the other side of the board when I had the switches pulled, but I'm not going to pull all of the switches again.

Was wondering whether anyone has a schematics or knows what switch connects to the Apps key, or has other advice on how to proceed. Here's a picture of my PCB in case anyone notices anything that I'm missing.


Offline suicidal_orange

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Re: Quickfire Rapid PCB Repair
« Reply #1 on: Sat, 05 September 2020, 16:34:05 »
The QFR has a replacement controller so you can look in the firmware to see what other switches it's connected to - EasyAVR is easiest to read for me (the keys are at the bottom, the second set of braces are the matrix positions)  This shows Apps is connected to .> (pink line) and on the other side via it's diode it should be connected to left arrow (orange line)

251113-0

So in theory shorting any pad on the pink to any on orange orange should output APPS, start far away and move both ends closer to the switch until you find the break then jump it.

Another random thought - why are the holes below APPS not filled with solder like all the rest of the extra positions in the bottom row?
120/100g linear Zealio R1  
GMK Hyperfuse
'Split everything' perfection  
MX Clear
SA Hack'd by Geeks     
EasyAVR mod
MX Brown 30g, HHKBish
Vortex OEM PBT
for See how the other half lives challenge!

Offline phoible

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Re: Quickfire Rapid PCB Repair
« Reply #2 on: Sun, 06 September 2020, 13:24:18 »
Thanks so much for your help! Turns out that I'm an idiot. After jumping across the switch per your diagram, still no keycode. Which makes sense because that key is actually a special FN key, so it wouldn't actually generate a keycode. Since I don't have the default keycaps installed, I couldn't see that. When I try to use it as a FN key, it works just fine for accessing the multimedia functions.

So the problem wasn't with my soldering, it was with my brain.  :-[

And as for why the bottom holes are unplugged on the app key, after I swapped the switch to make sure it wasn't the switch, my second thought was that I should just put in the switch upside down, so I desoldered those two holes. Since the upside down orientation is for the ISO layout, the position is slightly different and it didn't work. Overall not my finest moment, but in the end everything worked.

I now have a QFR with Gateron Reds (which I'm liking a lot more than expected after hating on linear switches for the past 10 years or so).
« Last Edit: Sun, 06 September 2020, 13:30:22 by phoible »

Offline suicidal_orange

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Re: Quickfire Rapid PCB Repair
« Reply #3 on: Sun, 06 September 2020, 14:11:02 »
Yup, that would do it

I've seen similar comments regarding ISO needing random things moving but it's not true - the only differences between ANSI and ISO are the split left shift and the big enter with small key next to it instead of two wide keys.  The extra position in the bottom row could be for a 7u spacebar or perhaps JIS (Japanese) but it's not ISO.

Glad you overcame your hatred of linears, can't be doing with all the mistypes due to too light springs myself but if you like them enjoy your newly smooth board :)
120/100g linear Zealio R1  
GMK Hyperfuse
'Split everything' perfection  
MX Clear
SA Hack'd by Geeks     
EasyAVR mod
MX Brown 30g, HHKBish
Vortex OEM PBT
for See how the other half lives challenge!

Offline phoible

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  • Posts: 106
Re: Quickfire Rapid PCB Repair
« Reply #4 on: Sun, 06 September 2020, 14:20:22 »
Thanks for the correction regarding ISO.

I'm most likely going to stay with my current favorite, which is an AEK64 with dampened cream ALPS. It's pretty much my endgame board (after using it for 4+ years and trying Topre and pretty much every Cherry variant). But it's nice to have some variety every now and then.

I actually was going to sell my Whitefox (due to not ever using it), and realized that I had a set of Gateron reds floating around since I built it up with some Gateron tactile clears rather than the included switches. So I figured that i might as well swap out the MX Blues in my QFR, since I have never really liked the Blues.

« Last Edit: Sun, 06 September 2020, 14:23:29 by phoible »