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Troubleshooting Bad Switch on NightFox

I got two NightFox keyboards, but wasn't as much a fan of the Hako Trues as I thought I'd be. So I swapped in Hako Violets into one keyboard, which went well and I was happy with the results, so I do the second keyboard.

Unfortunately, I must have screwed something up with Switch 64 (Left Alt by default). Doesn't work anymore, but did before I swapped the switches. I did what I could with my multimeter, and this is what I was able to confirm:

  1. Continuity is correct across the two solder joints. Open normally, closes when the switch is depressed.
  2. Diode check works from the switch's "positive" side through the diode (D64) and gives me the usual 0.6V drop when the switch is depressed and open normally. So the trace between the switch and the diode seems to be good.
  3. Also did a bit of voltage probing while plugged in, but because of the nature of the multimeter (it tends to give me averages if frequencies are high enough), and the keyboard matrix, I didn't expect to find anything interesting. Almost all the switches showed a ~4.9V drop compared to +5V, while S64 showed a 0V drop. Compared to VSS, it still shows a 0V drop, while the good switches show a measurable voltage difference.

Number 3 may just be a red herring, but I'm thinking either I managed to disconnect a via by accident that disconnected the switch, or break a trace. But I'm not sure where to go next trying to track it down.

My EE is rusty, so any help pointing me in the right direction from here, or correcting my thinking, would be appreciated.

Troubleshooting Bad Switch on NightFox

I got two NightFox keyboards, but wasn't as much a fan of the Hako Trues as I thought I'd be. So I swapped in Hako Violets into one keyboard, which went well and I was happy with the results, so I do the second keyboard.

Unfortunately, I must have screwed something up with Switch 64 (Left Alt by default). Doesn't work anymore, but did before I swapped the switches. I did what I could with my multimeter, and this is what I was able to confirm:

  1. Continuity is correct across the two solder joints. Open normally, closes when the switch is depressed.
  2. Diode check works from the switch's "positive" side through the diode (D64) and gives me the usual 0.6V drop when the switch is depressed and open normally. So the trace between the switch and the diode seems to be good.
  3. Also did a bit of voltage probing while plugged in, but because of the nature of the multimeter (it tends to give me averages if frequencies are high enough), and the keyboard matrix, I didn't expect to find anything interesting. Almost all the switches showed a ~4.9V drop compared to +5V, while S64 showed a 0V drop. Compared to VSS, it still shows a 0V drop, while the good switches show a measurable voltage difference.

Number 3 may just be a red herring, but I'm thinking either I managed to disconnect a via by accident that disconnected the switch, or break a trace. But I'm not sure where to go next trying to track it down.

My EE is rusty, so any help pointing me in the right direction from here, or correcting my thinking, would be appreciated.