issue with USB wiring (maybe)

[Parn]

Hi there

First of all, this is my first post here.
Reading for some time now and "extracting" all the info I need for my own/first GBZ.

I am not much of an electronic guy... learing soldering and desoldering on the fly...
But I already dropped a few evenings into this project.

And now I am stuck...
Just don't know what's up.

Hope you are able to help.

Situation:
Current builing my "prototype".
Soldering everything togther outside of the case and checking step by step, if everything works.

Just soldered USB Audio to my Pi (Zero W) and checked if it is working.
Some issues with getting it up as boot audio, but solved this quickly.
For this, I connected a USB keyboard and did all needed configuration (found in this forum).
Worked flawless... Nice clear audio on my headphones. Even working stereo (even due to my crappy soldering).

shut down the system and soldered a potentiometer between the USB audio and the head phone jack.
Booted up the system...

No USB working anymore.
Not when connecting the USB keyboard, neither the Leonardo Pro Micro (alternate to the Teensy... worked before as well).

I am sitting in front of this mess for at least one hour...
no idea, what might be wired wrong.
(Might be the Ground on the Potentiometer is wrong and I shorted the whole USB Bus? or some crap like that...)

Perhaps one of you can have a look onto this and tell me, if you see any potential issues.
Would be very nice.

Overview:

gbz_complete.jpg (4.12 MiB) Viewed 14687 times

Audio:

gbz_audio.jpg (5.36 MiB) Viewed 14687 times

USB-Hub:

gbz_usb hub.jpg (4.71 MiB) Viewed 14687 times

Power and Pi:

gbz_power.jpg (4.5 MiB) Viewed 14687 times

If you got any questions about this raw build... I will try my best to answer them.
Thanks in advance.

[Parn]

Disconnected the potentiometer and Audio Jack from The usb Audio... Keyboard still not working...

[Parn]

Seems I killed my USB Controller on the Pi
It did not recognize anything anymore.

Desoldered all parts step by step...
USB Audio, USB Hub...
Still not recognizing anything connected to USB.

Today I recieved a second pi...
Same img working absolutly fine in there.
USB is recognized.

So soldering a Potentiometer incorecctly to your usb audio can kill your pi...
not fun.

Still.... learned something from it.

What do you think? should I still be able to use the old USB hub?
Or will I kill the new pi with it as well?
disconnected the potentiometer, so...

any idea how to check that?

PI zero w are already sold out... so no third one I can order

[Lphillimore]

Bad luck mate. Just be sure to wire you potentiometer correctly?

I've seen posts on here where the volume pots have a back to front pin out.

Is it a B103? That's what most people use I believe and certainly what I use.

Personally with my builds that used USB sound I put the potentiometer between the Speaker and the headphone jack.

Working backwards my audio wiring goes:

Speaker ---> Headphone Jack ---> Volume Pot ---> Audio Amp ---> USB Sound card ---> USB Hub ---> Powerboard ---> Powerboost / Banggood.

Ground from Volume pot and Headphone jack both went to common ground on my PCB.

Grounds for rest went to Powerboard.

I can see an audio amp in your pic but it's un-used?

I too managed to kill the USB data port on one of my Pi Zero Ws - rather more recklessly though by clipping the casing of the micro USB away for a nicer fit for the Pi.

[ICMF]

Working backwards my audio wiring goes:

Speaker --> Volume Pot ---> Headphone Jack ---> Audio Amp ---> USB Sound card ---> USB Hub ---> Powerboard ---> Powerboost / Banggood.

Does that mean your headphone volume is fixed, then? Wouldn't it make more sense to have the volume pot before the headphone jack, so you can adjust headphone volume?

[tyler335]

Look at the back the package your potentiometer came in. You need to connect your ground to the "common" pin.

The "common" pin shown above is pin #1. Use this image as reference only though. Your potentiometer could have a different pinout.

[Lphillimore]

Working backwards my audio wiring goes:

Speaker --> Volume Pot ---> Headphone Jack ---> Audio Amp ---> USB Sound card ---> USB Hub ---> Powerboard ---> Powerboost / Banggood.

Does that mean your headphone volume is fixed, then? Wouldn't it make more sense to have the volume pot before the headphone jack, so you can adjust headphone volume?

A good callout and my mistake!

I of course meant:

Speaker ---> Headphone Jack ---> Volume Pot

I will amend my post.

[moosepr]

Something else to try. The data wires for the usb should be twisted to stop interference. Doesn't explain why the pot broke your pi, but it does help most usb issues

[Parn]

I can see an audio amp in your pic but it's un-used?

It is...
Since I am a beginner, I am working myself forward step by step.
So I was getting from Display to Controls to Power/Battery and finally audio.

Got the USB Audio working with the headphone...
Wanted to add the Pot to control the volume.
Last would have been to get the speaker working with the amp, if needed.
Read some comments here, which stated that the amp is not always necessary when using USB audio.

Look at the back the package your potentiometer came in. You need to connect your ground to the "common" pin.
The "common" pin shown above is pin #1. Use this image as reference only though. Your potentiometer could have a different pinout.

Got the Pot from Ebay.
No notes included in the package...
It was the only stereo pot i found with the correct mesearuments.

I "assumed" the wiring by the pictures on the ebay page:
http://r.ebay.com/3SGt7q
Might be a hard guess, but i understood the last picture (where they they show what to solder to use it with the GBA) that the unsolded pin would be GND.