Headphones Work, Speaker Squeals

Having trouble with your mintyPi build? Post your questions here!
omahgad
Posts: 10
Joined: Thu May 09, 2019 4:22 pm
Has thanked: 7 times

Headphones Work, Speaker Squeals

Post by omahgad » Thu May 16, 2019 7:00 pm

Hello!
Part two continuing the story from this thread:

https://www.sudomod.com/forum/viewtopic.php?f=34&t=7961

I've checked every spot for continuity as per the diagram and everything is beeping. When speaker is unattached, the sound works fine through the headphones. But when I solder the speaker onto the board, I get a loud squeal through the speaker and also through headphones when they are plugged in. Any thoughts?

Image
Image

I've scraped back the trace on both to see if I can get a fresh connection. I'm out of ideas :( Am I missing something? Thanks in advance!!

User avatar
LilTrublMakr
Posts: 241
Joined: Sun Aug 05, 2018 6:39 am
Has thanked: 23 times
Been thanked: 94 times
Contact:

Re: Headphones Work, Speaker Squeals

Post by LilTrublMakr » Thu May 16, 2019 7:23 pm

That is way too much wire for the speaker itself and way too much exposed wire on the speaker side. You basically only want enough wire exposed to cover the pad.

I also cant tell from looking at the pictures, and it may be flux, but it kinda looks like that there are bubbles in your soldering that could be a problem. I would get some IPA, clean that flux off, and reflow the gpio.

If the speaker seems to fix your problem, then the speaker might be bad. I believe these are 8 ohm 2 watt speakers but someone please clarify before getting a new one.

omahgad
Posts: 10
Joined: Thu May 09, 2019 4:22 pm
Has thanked: 7 times

Re: Headphones Work, Speaker Squeals

Post by omahgad » Thu May 16, 2019 7:31 pm

LilTrublMakr wrote:
Thu May 16, 2019 7:23 pm
That is way too much wire for the speaker itself and way too much exposed wire on the speaker side. You basically only want enough wire exposed to cover the pad.
Thanks for the quick response! I just roughly wired it up like this for the purposes of testing before I reassemble. The does the amount of exposed wire and length contribute to the squeal?

And I bought a backup pack of speakers from a link Helder sent me, so I should be covered for a few mishaps haha.

User avatar
waffe
Posts: 21
Joined: Wed Apr 24, 2019 10:35 pm
Has thanked: 14 times
Been thanked: 9 times

Re: Headphones Work, Speaker Squeals

Post by waffe » Fri May 17, 2019 12:25 am

Since you have concluded that the sound works from the headphone jack without the speaker plugged these are the things you could do to rule out some stuff. Might be more options but here is what I can help with:

-Test the speaker by itself to exclude that there is something wrong with it. You can look up simple circuits for speakers online to test it or use an arduino or a signal generator.

Check the signal from the board with the speaker wires connected to an osiclloscope i.e remove the speaker and connect the wires to an oscilloscope. Then you play a sine wave from the raspberry pi and it should show up on the scope. You can do a visual inspection of the signal and then do a FFT on the scope to see what frequencies you are getting. So you can check for noise or check if something does not add up.

-Use some isopropyl alcohol to remove all that ugly grime from the pcb, when soldering the wires twist them to reduce the emf that might happen and reduce noise because the magnetic fields cancel out.

-You can check under a microscope on your pcb connection to see if its legit, there might be some issues with your soldering cause it aint pretty.

-Now if you fucked up your soldering you can actually wire the speaker directly from the headphone jack as in the image below since the pcb probably just extends the connections and routes it to a better physical location. Note that in the picture the soundcard and potentiometer is probably already built into the board.


Image

Edit: formatting and clarification since I was in a rush when I wrote it

omahgad
Posts: 10
Joined: Thu May 09, 2019 4:22 pm
Has thanked: 7 times

Re: Headphones Work, Speaker Squeals

Post by omahgad » Sun May 19, 2019 9:58 pm

waffe wrote:
Fri May 17, 2019 12:25 am
Check the signal from the board with the speaker wires connected to an osiclloscope i.e remove the speaker and connect the wires to an oscilloscope. Then you play a sine wave from the raspberry pi and it should show up on the scope. You can do a visual inspection of the signal and then do a FFT on the scope to see what frequencies you are getting. So you can check for noise or check if something does not add up.
Thanks for the response and taking the time to help troubleshoot!! Unfortunately I am a very beginner hobbyist with this kind of stuff, so I'm not at the level where I have access to an oscilloscope.

I did buy a 10 pack of additional speakers and tested out about three more with the same squealing results.

I also spent some time reflowing solder to make sure connections were solid and there was no bridging(?) between spots.

I think my last resort is to wire the speaker to the headphone jack, but I'm not entirely sure which goes where as my board is different from the one you attached.

Image

User avatar
waffe
Posts: 21
Joined: Wed Apr 24, 2019 10:35 pm
Has thanked: 14 times
Been thanked: 9 times

Re: Headphones Work, Speaker Squeals

Post by waffe » Mon May 20, 2019 12:08 am

Cant really say what goes where. You should be able to trace the lines out on the pcb or you can ask the creator of the board.

User avatar
LilTrublMakr
Posts: 241
Joined: Sun Aug 05, 2018 6:39 am
Has thanked: 23 times
Been thanked: 94 times
Contact:

Re: Headphones Work, Speaker Squeals

Post by LilTrublMakr » Mon May 20, 2019 5:32 am

Do you have solder wick that you can use to desolder the headphone jack off and then bridge the speaker bypass and see if it's something to do with the headphone jack?

User avatar
Helder
Trailblazer
Trailblazer
Posts: 2735
Joined: Thu May 05, 2016 8:33 am
Location: Fall River, MA
Has thanked: 1398 times
Been thanked: 3064 times

Re: Headphones Work, Speaker Squeals

Post by Helder » Mon May 20, 2019 11:55 am

Image

use this here for the alternate points for the speaker from the headphone socket.
My Sale Threads:

Retro PSU, 3.5A output!


Chat with me and other members


Don't contact me about obtaining my board files (as you will not get them). Don't contact me about any of my boards if they are sold out, they will be restocked as soon as I can get them.


Don't support thieves like ckliang who copied my AIO to resell and is now cloning the mintyPi, support the original creators and not the thieves!

omahgad
Posts: 10
Joined: Thu May 09, 2019 4:22 pm
Has thanked: 7 times

Re: Headphones Work, Speaker Squeals

Post by omahgad » Mon May 20, 2019 12:19 pm

Helder wrote:
Mon May 20, 2019 11:55 am
use this here for the alternate points for the speaker from the headphone socket.
Thanks! Is it possible to have the alternate points as well as the headphone socket soldered in?

User avatar
Helder
Trailblazer
Trailblazer
Posts: 2735
Joined: Thu May 05, 2016 8:33 am
Location: Fall River, MA
Has thanked: 1398 times
Been thanked: 3064 times

Re: Headphones Work, Speaker Squeals

Post by Helder » Mon May 20, 2019 1:28 pm

omahgad wrote:
Mon May 20, 2019 12:19 pm
Helder wrote:
Mon May 20, 2019 11:55 am
use this here for the alternate points for the speaker from the headphone socket.
Thanks! Is it possible to have the alternate points as well as the headphone socket soldered in?
It's the same exact points with or without socket soldered on :roll: . If the socket is soldered on you solder it to the socket leg soldered on that spot.
My Sale Threads:

Retro PSU, 3.5A output!


Chat with me and other members


Don't contact me about obtaining my board files (as you will not get them). Don't contact me about any of my boards if they are sold out, they will be restocked as soon as I can get them.


Don't support thieves like ckliang who copied my AIO to resell and is now cloning the mintyPi, support the original creators and not the thieves!

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests