+2B sound output problem

[TheMartian]

Hi all!

So, since a week or so, I've noticed that the sound output on my +2B is very distorted. It is a Spanish model, board Z70833 Issue 2 I think, because it has the capacitor between pins 10 and 11 of the Z80.

The distortion affects the ULA sound only. The EAR input is not affected, and I think the MIC output isn't either, but the BEEP sound is. It sounds very distorted, and when I tried this program:

10 FOR I=0 TO 60: BEEP 1,I: NEXT I

It sounds particularly awful on BEEP 1,48. This means the distortion affects more in a particular, narrow, frequency.

The sound is distorted both in the headphones and in the TV output. So I guess the problem is either C204, TR200, or maybe one of the resistors around. Because of the frequency response I feel inclined to think that it's the capacitor.

Any ideas, before I order the parts and start changing stuff?

Thanks!

[TheMartian]

Turns out it was the screw in the cassette player board. I tightened the screw, and added some solder on the side. Now it sounds clean again, and tapes seem to load more reliably.