Lynx II Strange No Audio Issue

[ThatGuyUKnow]

I have an Atari Lynx II with no audio. Everything else on the handheld works correctly. I verified the speaker is good. I thought it might be the headphone jack so I swapped it out with a known good with no change. I thought it might be the volume taper so I switched that out with a known good with no change. The board needed new caps so I replaced the electrolytic capacitors with no change. The audio circuit is getting a proper 5V from VCC. I traced the circuit from pin 32 of the rom cart through Hayato to U7 and U12 checking all components for shorts on caps and checking resistor values but found nothing. I replaced U5, no change, U12, no change, U7, no change, Hayato, no change. I down to checking every trace in the audio circuit for continuity. Any advice or other troubleshooting suggestions?

[+karri]

I had a similar Lynx with no audio. The way I found a broken trace was to start tracing the audio from the pin where the audio leaves Hayato. In my case the audio never reached the op amp. So I just soldered a wire to get it there. My motherboard was a bit different so I was not able to follow the trace with the schematics.

 

I just put two wires on the headphone connector. Connected one wire to ground and with the other I poked pins and listened where the sound went.

[ThatGuyUKnow]

17 hours ago, karri said:

I had a similar Lynx with no audio. The way I found a broken trace was to start tracing the audio from the pin where the audio leaves Hayato. In my case the audio never reached the op amp. So I just soldered a wire to get it there. My motherboard was a bit different so I was not able to follow the trace with the schematics.

 

I just put two wires on the headphone connector. Connected one wire to ground and with the other I poked pins and listened where the sound went.

Yeah I was thinking it must be a trace issue. Time to get to work with a multimeter.