Author Topic: PCB Single Column Not Responding  (Read 1104 times)

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Offline sanlouie_7

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PCB Single Column Not Responding
« on: Fri, 11 June 2021, 01:31:18 »
Hi all, first post so I hope that I am doing this correctly. I recently purchased a keyboard secondhand that was working fine the several days until a single column of keys stopped responding (F1, 1, Q, A, WIN). I have just about no experience when it comes to this and when using a multimeter, I had absolutely no clue what was looking for. However, I did this one thing that stood out to me (again, no experience) and figured that maybe it could be useful in diagnosing the problem.

The PCB is millmaxed and I went ahead and flowed a bit more solder in case there that could have been an issue with the affected keys. There seems to be continuity along the vertical traces for the affected column (I think) but yet nothing seems to happen when a switch is installed.

Here is a demonstration of what I found. WARNING: sound may be loud and I apologize in advance. Again, I have no idea what I am doing but I am certainly willing to learn as getting a replacement PCB may be next to impossible anyhow :(


If there's anything else I should know or anything else I could do through this process, I can do it as soon as possible. I appreciate the help in advance!


Offline suicidal_orange

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Re: PCB Single Column Not Responding
« Reply #1 on: Fri, 11 June 2021, 03:12:19 »
Confirming all the switches are connected is a good start :thumb:

As they are connected the most likely answer is that where the column should connect back to the controller chip has become detached.  I see a nice red PCB so if you post a pic of the affected area I'll have a look and maybe suggest some poke testing, or maybe an easy fix.  If it's a DIY board the name would also be good to see what goes to where in the firmware.

Nearly forgot - welcome to geekhack :)
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Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #2 on: Fri, 11 June 2021, 09:47:18 »
Confirming all the switches are connected is a good start :thumb:

As they are connected the most likely answer is that where the column should connect back to the controller chip has become detached.  I see a nice red PCB so if you post a pic of the affected area I'll have a look and maybe suggest some poke testing, or maybe an easy fix.  If it's a DIY board the name would also be good to see what goes to where in the firmware.

Nearly forgot - welcome to geekhack :)

Thanks!

I checked all the switches when installed and with tweezers using a switch hitter everything registered except for the affected keys as part of the column (F1, 1, Q, A, WIN). The PCB is an Octagon Ver2.0.

I have taken pictures of the front and back of the PCB. Please let me know if there may be anything else that could be helpful.

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Offline suicidal_orange

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Re: PCB Single Column Not Responding
« Reply #3 on: Fri, 11 June 2021, 10:53:36 »
Wow, it's a classic :)

Not the friendliest of designs but I think the trace we're looking at is the green one where the vertical gap and the connection to the column are visible on the front of the board..  Hopefully if you touch a wire between the blue dot and the pin at the end of the green trace on the chip it will type an A?

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Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #4 on: Fri, 11 June 2021, 11:36:49 »
Wow, it's a classic :)

Not the friendliest of designs but I think the trace we're looking at is the green one where the vertical gap and the connection to the column are visible on the front of the board..  Hopefully if you touch a wire between the blue dot and the pin at the end of the green trace on the chip it will type an A?

(Attachment Link)


I hope I'm doing it right. I'm touching a wire from the blue dot to the pin(hole?) that is shown in green next to the chip, correct? I am keep trying and hopefully get something.

Unfortunately, with my few tests of doing so, I have not been able to achieve any registers from A (or other keys within the column).

Offline suicidal_orange

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Re: PCB Single Column Not Responding
« Reply #5 on: Fri, 11 June 2021, 12:16:44 »
Happily you're not doing it right (you want it to work!) - the hole is insulated by red stuff, you need to touch the shiny leg on the chip.
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Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #6 on: Fri, 11 June 2021, 12:35:08 »
Happily you're not doing it right (you want it to work!) - the hole is insulated by red stuff, you need to touch the shiny leg on the chip.


Uh oh. I see what's wrong now. The whole PCB isn't registering anymore and I'm fairly certain that this just happened recently. I also don't know if I can reset it since I can't hold the most top-right button to reflash.

I guess this is a new problem to resolve altogether? I'm really not sure but wow that was really unfortunate :(


Also: PCB is still recognized by Windows, so I didnt have any issue there.
« Last Edit: Fri, 11 June 2021, 12:51:16 by sanlouie_7 »

Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #7 on: Fri, 11 June 2021, 12:45:59 »
Happily you're not doing it right (you want it to work!) - the hole is insulated by red stuff, you need to touch the shiny leg on the chip.

Also, I don't suppose this single unset millmax could be resulting in anything? But I just figured that I should it just in case.

I also reflowed some solder on the mini-usb connector (on the front side) out of desperation, but it was hardly a touch of solder or heat.

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Offline suicidal_orange

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Re: PCB Single Column Not Responding
« Reply #8 on: Fri, 11 June 2021, 12:52:39 »
Well it will be hard to test one column if nothing works!

I'm not seeing a reset button or pair of pads, if you're careful you can short two pins on the square chip to put it in bootloader (flash) mode but they are very small.  Looking at your pics the USB port soldering doesn't look great - could that be the problem or does the computer detect it properly?
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Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #9 on: Fri, 11 June 2021, 12:55:45 »
Well it will be hard to test one column if nothing works!

I'm not seeing a reset button or pair of pads, if you're careful you can short two pins on the square chip to put it in bootloader (flash) mode but they are very small.  Looking at your pics the USB port soldering doesn't look great - could that be the problem or does the computer detect it properly?

Yeah the computer is able to detect it as far as I can tell. There's an audible noise when connected and it also appears in the device manager.

Would it help to try to fix that up a bit?

And let me see what I can do about shorting two pins. How would I go about doing this exactly? Sorry quite a lack of knowledge!


Offline suicidal_orange

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Re: PCB Single Column Not Responding
« Reply #10 on: Fri, 11 June 2021, 13:06:01 »
The socket won't do anything, it's just an extension of the hole.

You need to short the RESET pin 13 to a Ground pin, 23 looks easiest to hold one end of a thin wire against.  Do not short RESET to pin 14 next to it as 5V full current may damage it.  There's a dented dot in the top of the chip that matches the one on the pinout, I think it's near the edge of the board but can't be sure.  I'm also assuming this is an Atmel ATMega32u4 as that's what the firmware says - if you can read something very different on the chip don't try this.

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Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #11 on: Fri, 11 June 2021, 13:33:09 »
The socket won't do anything, it's just an extension of the hole.

You need to short the RESET pin 13 to a Ground pin, 23 looks easiest to hold one end of a thin wire against.  Do not short RESET to pin 14 next to it as 5V full current may damage it.  There's a dented dot in the top of the chip that matches the one on the pinout, I think it's near the edge of the board but can't be sure.  I'm also assuming this is an Atmel ATMega32u4 as that's what the firmware says - if you can read something very different on the chip don't try this.

(Attachment Link)

So I successfully managed to reset the PCB. However, now the PCB isn't being recognized by QMK Toolbox. When I plug in the PCB, the underglow lights blink for a split second. There is still an audible noise when plugged back in.

Am I supposed to hold reset while plugging it back the mini-usb cable back into the port? LIke how it would when going into DFU Mode?

Offline suicidal_orange

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Re: PCB Single Column Not Responding
« Reply #12 on: Sat, 12 June 2021, 03:13:25 »
Unfortunately I haven't used this PCB so I don't know what it's normal behavior is, and I use Linux not QMK toolbox which (as I understand it) is a frontend for lots of background flashing stuff.   On my GH60 you plug in the USB then short RESET to ground and it goes to bootloader mode (DFU in this case) then you run the flash command.  From reading the QMK newbie guide you should see a message in yellow (though the screenshot is white on blue :confused: )  Is your toolbox set up correctly (this is an old board, not sure if you have many others or have reformatted Windows since you last flashed it)

What device does it show as when you plug it in and after shorting RESET?  A sound with no 'Device not recognised' message when you plug it in means it's not dead, that's the main thing.
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Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #13 on: Sat, 12 June 2021, 12:48:18 »
Unfortunately I haven't used this PCB so I don't know what it's normal behavior is, and I use Linux not QMK toolbox which (as I understand it) is a frontend for lots of background flashing stuff.   On my GH60 you plug in the USB then short RESET to ground and it goes to bootloader mode (DFU in this case) then you run the flash command.  From reading the QMK newbie guide you should see a message in yellow (though the screenshot is white on blue :confused: )  Is your toolbox set up correctly (this is an old board, not sure if you have many others or have reformatted Windows since you last flashed it)

What device does it show as when you plug it in and after shorting RESET?  A sound with no 'Device not recognised' message when you plug it in means it's not dead, that's the main thing.

Unfortunately, QMK is not recognizing the device in any way that I try to get it to connect. My device manager list also isn't having the PCB appear as a ATMEGA32U4 device either, so I was thinking that might be a problem as well. I believe my problems only started to occur after I had flashed with QMK. A reddit user posted about the same experience, and I guess flashing with Atmel FLIP or with the 02D could do the trick?

But to answer your question, I have a feeling that my toolbox was not set up properly and that may have caused some issues.

Offline sanlouie_7

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Re: PCB Single Column Not Responding
« Reply #14 on: Sat, 12 June 2021, 14:04:26 »
Oh I guess Windows also isn't recognizing the device properly. It seems that when I plug in the board, it shows as "Unknown USB Device (Device Descriptor Request Failed)" in the Universal Serial Bus controllers tab in Device Manager.