stuck keyboard input

[spider2k]

im finally getting one of my circuit sword lite kits together and have an issue with key config.

when i try to input the buttons it was acting funny and skipping inputs. if i hold the mode and press A to turn on the keyboard even before i go into the config i have a down key ghosting issue. i thought it was a stuck d pad so i took it apart and even with the physical buttons out it still does it.

thoughts?

[kite]

with it powered off, could you measure with a multimeter the resistance of the PCB contacts? If you look carefully you can see that the fingers of the PCB contacts are in two halves, get one probe on one side and the other on the other.

The expectation is that it reads as 100k ohms, so that's the kind of range that you're looking at. Based on that I can offer some other tips. It would be a good idea to measure some of the other working pads and see if it all reads the same or different

[spider2k]

with it powered off, could you measure with a multimeter the resistance of the PCB contacts? If you look carefully you can see that the fingers of the PCB contacts are in two halves, get one probe on one side and the other on the other.

The expectation is that it reads as 100k ohms, so that's the kind of range that you're looking at. Based on that I can offer some other tips. It would be a good idea to measure some of the other working pads and see if it all reads the same or different

got it. will do and report back.

[spider2k]

with it powered off, could you measure with a multimeter the resistance of the PCB contacts? If you look carefully you can see that the fingers of the PCB contacts are in two halves, get one probe on one side and the other on the other.

The expectation is that it reads as 100k ohms, so that's the kind of range that you're looking at. Based on that I can offer some other tips. It would be a good idea to measure some of the other working pads and see if it all reads the same or different

21 Mohms. the rest are all 105k.

[kite]

Ok cool, right so the pull up resistor on that pad is not soldered correctly. In the picture below the BRIGHT red parts of the picture are the traces for the DOWN button. You can see that it enter the IC but is also connected to the resistor network "RN4" (this is 4x individual resistors all packaged into that small component). This is the 100k resistor. You can see that on the RIGHT side of RN4, all the legs of it are connected together, this is the 3.3v side. The other side is then linked individually to each button pad.

Could you take a close inspection of this component? If you can take a macro picture of it in focus in bright light I can offer tips on what I can see (i have experience in this area!).

In order to fix, the solder needs to be applied to link it back together. IDEALLY if the 3.3v side is the side missing solder, it will be very easy (just apply a blob of solder to the RIGHT side only, doesn't matter if they all bridge together because they're MEANT to be connected together If it's the other side, it's a bit trickier.. you are welcome to give it to go, and/or you can send me an email and we'll sort out a return and I'll repair it for free. You could even have a go at doing it and STILL return it to me if you can't do it, it won't invalidate my offer at all, but might save some time

Let me know what you think or can see!

Alternatively if you have a 100k resistor, you can wire it up in any way to that signal (from the button pad area perhaps) to 3.3v

Screenshot from 2019-07-09 15-40-06.png (34.65 KiB) Viewed 4503 times

[spider2k]

Ok cool, right so the pull up resistor on that pad is not soldered correctly. In the picture below the BRIGHT red parts of the picture are the traces for the DOWN button. You can see that it enter the IC but is also connected to the resistor network "RN4" (this is 4x individual resistors all packaged into that small component). This is the 100k resistor. You can see that on the RIGHT side of RN4, all the legs of it are connected together, this is the 3.3v side. The other side is then linked individually to each button pad.

Could you take a close inspection of this component? If you can take a macro picture of it in focus in bright light I can offer tips on what I can see (i have experience in this area!).

In order to fix, the solder needs to be applied to link it back together. IDEALLY if the 3.3v side is the side missing solder, it will be very easy (just apply a blob of solder to the RIGHT side only, doesn't matter if they all bridge together because they're MEANT to be connected together If it's the other side, it's a bit trickier.. you are welcome to give it to go, and/or you can send me an email and we'll sort out a return and I'll repair it for free. You could even have a go at doing it and STILL return it to me if you can't do it, it won't invalidate my offer at all, but might save some time

Let me know what you think or can see!

Alternatively if you have a 100k resistor, you can wire it up in any way to that signal (from the button pad area perhaps) to 3.3v

Screenshot from 2019-07-09 15-40-06.png

i will look at it. do you think i could get away with fluxing RN4 and reflowing the whole thing with hot air?

also i havent forgotten the package i was sending you, im just really lazy. it's still coming at some point!

[spider2k]

ok now it's reading but every pad is 150k and climbs very incrementally.

[kite]

Yeah flux + reflow is fine, I assume that is what you have done? Does it now show this same behaviour when on and you use the input?

You can also have it powered on and read the voltage of the button pads, it should read 3.3v

[spider2k]

Yeah flux + reflow is fine, I assume that is what you have done? Does it now show this same behaviour when on and you use the input?

You can also have it powered on and read the voltage of the button pads, it should read 3.3v

buttons are good. now i just have to figure out the software.

[kite]

Awesome glad to hear, sorry about the defect in the first place! Let me know if you need help with anything else