Well, this has been very weird.
I desoldered and cleaned the offending keys. No change.
After a few minutes testing, the sound went out completely. No sounds whatsoever from any app.
I gently removed the SN76489AN (sound chip) from the socket to test it, and surprise... two of its oxidized legs remained in the socket.
I cleaned the socket and the sound chip went in the trash, waiting for a replacement to arrive.
Then I checked if the system was still ok.
To my surprise, the keyboard is now working as expected, so I can only conclude that the problem was the sound chip.
I desoldered and cleaned the offending keys. No change.
After a few minutes testing, the sound went out completely. No sounds whatsoever from any app.
I gently removed the SN76489AN (sound chip) from the socket to test it, and surprise... two of its oxidized legs remained in the socket.
I cleaned the socket and the sound chip went in the trash, waiting for a replacement to arrive.
Then I checked if the system was still ok.
To my surprise, the keyboard is now working as expected, so I can only conclude that the problem was the sound chip.
Statistics: Posted by DDT — Thu Jan 23, 2025 2:25 am