Hi, I have recently purchased a Sony M-9G as a parts donor for my M-1PD. However, I'd like to get it running as well. It has several issues - most importantly, almost no sound. After playing a microcassette for maybe a minute, it got increasingly more quiet. Now there's barely any sound. Also, recording does not work. Finally, the most annoying fault - when playing through the speaker, it emits a very high pitched signal, I think somewhere around 4-5kHz. I checked the head - it's clean. The microphone is well soldered to the motherboard. My only uneducated guess is that this is caused by motor feedback, but even if it is, I don't know how to fix it. I would greatly appreciate any help on what's causing these problems.
It plays fine through the headphones? Maybe the speaker went bad, I don't know the best way to check the speaker besides seeing if there's continuity.
