No audio from pHAt DAC now


#1

I bought a new Pi zero and a 40 pin male to male header. I soldered the header into the Pi zero’s holes, and soldered the 40 pin hammer header onto the pHAT DAC, but only some of the pins as per pics.
After I inserted a sd card with musicbox on and it all loaded up, when I selected a music track or radio station there is no sound from the speaker. When I move the phono plug in and out, I get static? noise, but that’s all.
Have I missed something?


#2

Please don’t take this the wrong way but I think your issue is a poor soldering job. Have a look at this, and maybe consider redoing it.
https://learn.pimoroni.com/tutorial/sandyj/the-ultimate-guide-to-soldering


#3

Looks like BCM18 (the i2s clock pin - https://pinout.xyz/pinout/phat_dac) is not soldered at all?


#4

alphanumeric, could you tell me where or what part of each board is a poor soldering job. Is it all or just some of it.

The pHAT DAC used to work with no soldered pins on the hammer head.


#5

Pin 3 on the Pi (SDA) for one doesn’t look good. I see a few that look cold soldered. Some with not enough solder, and a few with a bit too much. I didn’t see any that looked like they were bridged (shorted) to an adjacent pin.
Honestly, I’d watch the video, then carefully do them all over again. Some will just need to be reflowed. Clean the tip, then touch a PIN so the solder melts. Then make sure the tip touches the PIN and the pad at the same time. Then remove the tip by moving straight up. Have a look at this. https://learn.adafruit.com/adafruit-guide-excellent-soldering/common-problems


#6

I have soldered a 40 pin header onto the scroll hat hd , and it works fine on the end of a mini black hak3r and ribbon cable. Yes, I know it may well use different gpio pins, but I was just checking it would or not.


#7

I got around to resoldering the 40 pin header pins on to the zero, and although it wasn’t the best soldering, I went over every pin with a thicker solder wire from 21awg to 18awg just to put a bit more solder on each pin as needed.

Just for info, I am using a 2.3mm soldering bit on an electric iron, and as I had have this for too many years, I can’t remember what make it is.

After loading music box up and a connected speaker, it now works.


#8

Fixed is always nice. Soldering is an acquired skill. Practice makes perfect. My background is in electronics so its second nature to me now. My Raspberry Pi projects have got me back doing more soldering than I done in years. I’m actually enjoying getting my soldering back out and building circuits etc. Anyway, enjoy your now working sound project.


#9

When I was a Radio Ham many years back now, I did a lot of soldering building power supplies and other associated bits for my hobby. I also had to trace out a circuit from a magazine, then put that onto a copper sided board and trace the circuit onto that. Now I can’t remember what the next part was but the board was placed in an acid bath to remove the unwanted copper.
After that was done , all the holes had to be drilled out using a 1.6mm or smaller drill on a hand drill. Then you could start soldering all the parts, ie resistors, mosfets, capacitors, as well as having to wire round your own tuning part and then lacquer it all over.

It’s not something I’d want to go back to now!

Now I have done a bit of soldering today etc, I don’t mind doing some more, now I know what to look out for so to speak.


#10

I did a bit of circuit board design early on in my career as an Electronic technician. Our boards already had the photo resist on them. You did your artwork up on clear Mylar. Then put both under a light. Then in chemicals to strip the coating off where you wanted the board etched. Then etch the board, etc, etc. Fun times, at the time, not all that interested in doing it now. The simple bits of circuit I do up these days can be done on perf board. Well Proto Boards as Adafruit and Pimoroni call them. Anything any more complicated than that and I look for something ready made.

I’ve done a lot of work in radio communications, maintain and repair mostly. VHF, UHF, MF, HF. On the civil aviation side. Ground based ground to air communications, radio navigational aids, instrument landing systems, radar ,etc. Retired now. I thought about becoming a HAM operator years back but never followed through with it. I just listen on my short wave radio.


#11

You’ve probably come across it, but I spent ages on this web-based software defined-radio portal: http://www.websdr.org/

Amazing what gurgley, crazy and haunting noises you can hear- and be totally clueless about- only to have someone demystify them as the intermittent pulse of a radar.


#12

Yeah, you’ll hear some pretty strange stuff on shortwave. I can still remember finding my first numbers station. Cue the James Bond sound track.


#13

Yes, I heard those noises as well whilst tuning my 1/2 wave dipole on 7 mhz as well as 3.6 mHz, trying to get the best SWR on both bands. I also had a a 14 mHz and 28 mHz quad antenna up at about 6 or 7 meters high, which I could talk to radio hams in California some days when the skip was right.