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V3 bad voltage (no audio)

Posted: Sat Jan 04, 2020 7:43 pm
by Strikepig
Good evening all,

Issue: no sound at the speaker or headphones.

I just completed the soldering of the Pi to the PCB and ran a continuity test and all points passed according to the diagram.
Applied 5v thru USB for system test and booted fine minus sound.
Reading thru the wiki here I saw troubleshooting steps and ran those. Continuity passes for all audio points.
The issue I'm seeing is 3.1v at D1 and 1.7v at U2.
I also don't have the equipment nor the know-how to reflow U2 if that's what's required.

The other (small) issue is the screen PCB was received separated from the screen back (on the lower/ribbon edge). The screen works if the two are squeezed together. Guessing this will resolve itself once the build is complete and all is snapped together in place.

Thanks to Helder and Wermy for the excellent design and engineering of this sweet machine!
Looking forward to your response and to reliving old memories.

Re: V3 bad voltage (no audio)

Posted: Sun Jan 05, 2020 8:46 am
by Helder
As mentioned in the wiki and I'm sure numerous threads no audio means no 5V, so 100% the 5v GPIO (there are 2 of them) does not have continuity meaning a weak joint so you need to resolder those points.

On the new boards there is a dedicated 5v test pad which is likely the one you have so no need to test on D1 but it's ok if you do. Here is a picture with the points to resolder and check continuity (not voltage since it's coming from the USB cable you're using)