Worklog The DWii

[Gi0V1Z]

Hello BitBuilt!!!
This is my fist project, the DWii, it will have:
-7” TFT display (wired with VGA)
-Bluetooth
-Wi-Fi
-MX chip
-PMSv2-lite
-USB-C PD PCB
-U-AMP
-GC+ 2.0
-2x LRA vibration motors 2V
-4x INR18650-35E 3500mAh 10A 1-35W

I had troubles with my first trim, so I asked for help in the forum without any response (here is the link), so I bought a second one.
I’ve relocated the U10 before trimming the Wi, and it works fine:

After the relocation I trimmed the Wii:

After the trim I tested the board with my multimeter, I know this multimeter is old as fuck, but this is what I have at the moment
1.15V:

1V

1.8V

3.3V:

It seems to be ok to me, except for the 3.3V resistance, I’m not sure about it because it should be around 16kOhm but I really don’t know even how to read this.
I tested that the first marks are 100Ohm for each one (like in the previous photos), and the ”5” is 500Ohm, I can suppose that the “1” next to the previous “5” stands for 1000Ohm.
If I am right there is a short somewhere...

 

[Wesk]

Anything above 3kOhm on 3.3v is fine.

 

[Gi0V1Z]

If my supposition is true the resistance on 3.3V is around 800-900Ohm, do you agree?

 

[Wesk]

If my supposition is true the resistance on 3.3V is around 800-900Ohm, do you agree?

I have no idea how to read your multimeter so I cannot say.

 

[Notjohnny]

If my supposition is true the resistance on 3.3V is around 800-900Ohm, do you agree?

Given the XK scale and the markings on the Ohms line I'm pretty sure that 800-900 is the correct resistance reading (from right to left it goes 0, 0.5, 1, 2, 3.... multiplied by scale xK=x1000) if you use the x10 scale it should be in a range of 0 to 5kOhms so it might be easier to confirm and more accurate.

You might also consider getting yourself a digital multimeter, those analog things can usually read voltage variation faster but its waaaay easier to read a reading (heh) on a digital one

 

[Gi0V1Z]

Given the XK scale and the markings on the Ohms line I'm pretty sure that 800-900 is the correct resistance reading (from right to left it goes 0, 0.5, 1, 2, 3.... multiplied by scale xK=x1000) if you use the x10 scale it should be in a range of 0 to 5kOhms so it might be easier to confirm and more accurate.

You might also consider getting yourself a digital multimeter, those analog things can usually read voltage variation faster but its waaaay easier to read a reading (heh) on a digital one

I’ll take a look for a new multimeter, maybe on Amazon, in the mean time I took a 1kOhms resistance from a junky pcb, and verified on digikey resistance calculator then I tested it and this is the result:

Using XK:

Using x10:

 

[Gi0V1Z]

Good news, today I tested again my trimmed wii, but accidentally switched the negative and positive wires of the multimeter, and I saw a different read around 2kOhms...

So I thought (maybe I’m wrong) that if there really was a short on 3.3V it should always be the same annoying 800-900Ohms of the previous photo, that made me want to try...

It works, but i don’t know why it can’t read the usb.
I tried soldering to the other usb but nothing, I also tested with the multimeter and it is ok, also checked the D+ and D- but they are fine.
Really don’t know why...

 

[Wesk]

You need to twist the USB wire tightly, they are differential pairs. You should also keep the USB wires relatively short.

 

[Gi0V1Z]

You need to twist the USB wire tightly, they are differential pairs. You should also keep the USB wires relatively short.

Thank you Wesk, now it works.
I’ll wait for my laptop, cause it’s under repair, then I will complete the 3D models...