HEADPHONE JACK DISTORTED SOUND FULL

Starting with C678 and C679, because I might have used solder paste on those. But I'll be taking all of the caps off and looking for problems underneath. Luckily I didn't use paste and hot air for all of the caps because I didn't like the results. It must have spread underneath the caps when I was cleaning with IPA. I found unflowed solder paste underneath. It's harder to make that mistake when using SMT/SMD caps.ДЄlso last night, I removed C670, C674, C675, and C884. As for polarity, they are correctly oriented. I checked several vias and continuity is good. Anyway, the board is pristine now, at least the parts that aren't covered by components.

If you have sound out of both channels, then there's your problem, if not, then it's something else. All you need is an audio file that plays on either the left or right channel only. I guess I got lucky that the board was caked in flux at the factory and the flux frosting protected the PCB from the leaky caps. This would happen if the common ground connection is broken somewhere in the audio out. Last night I looked at he entire PCB for trace damage, but couldn't find any. Here is a video I made with some examples of the sound distortion: Lower frequencies are seem like they are more prone to cause distortion. It seems that the louder the sound is, the worse the distortion. It's not specific to the PSG, ADPCM, or CD audio. The sound distortion problem affects all audio.

I'll remove three other caps next to the volume knob and replace them soon. When I fired up the Duo, the left channel on the headphone jack started working, but the right was gone! WTF? I expected either both channels gone, or the right channel to still be working. I then removed C671 and cleaned up because it looked a little dodgy.

HEADPHONE JACK DISTORTED SOUND FULL

The sound is now at full volume out of the headphone jack. I removed the volume knob to clean it, but I haven't put it back in. In regards to the missing left channel on the headphone jack: The distortion problem seems unrelated to the missing left headphone jack, because it sounds distorted through both the AV and headphone jack. But the was no change the distortion is still there. But I've cleaned it completely and switched out a couple of caps that that weren't on perfectly. I haven't had much time to work on the Duo until the past couple of days.

Headphone jack distorted sound