Hardware GBA GBA SP that had audio no longer does

[binglet0n]

So I bought a GBA SP from a local game store, and it worked totally fine, even the audio. I then modded it with a GBA accelerator and a new shell + screen, but while testing I noticed the audio had disappeared after hearing a weird static noise from the speaker. I figured it was no big issue since it had been working so I continued, but it still isn't working and I'm at my wits end. I've tested the slider and it was fine, the speaker is good and the 2 other replacement speakers also don't work with this board, and I even replaced the AMP and audio capacitor to no avail. My guess is something in the audio circuit got shorted but I can't for the life of me figure out what it could be, as all of my continuity testing makes it seem like everything is perfectly fine. The board is an AGS-CPU-21 and is in what looks to be great condition before and after modding it.

I did use the circuit info from the Gekkio github page and while it's been helpful, I still can't pinpoint my issue. Any help would be appreciated. Also, I modded it with a Type-C Charge Mod and the audio still worked after that.

 

[moon_rabbit]

This may be a 3.5mm stereo jack problem.

If there is a sound coming from the jack
The jack needs to be replaced.

 

[binglet0n]

GBA SPs don't have stereo jacks; you have to buy an adapter for them to use with the transfer port. I did order one a day or two ago to test if there is audio coming from that, but the speaker had been working before so I'm almost certain the transfer port isn't the fault here.

 

[moon_rabbit]

I forgot that SP doesn't have a 3.5mm.

I think the fastest way is to remove all mod and check audio signal with an oscilloscope.