Ok forgive me. I made an embarrassing mistake. The solution was pretty simple and overlooked!
The wiper of that volume pot went off to the jack - which was shorting the two terminals. So the signal was shorting to ground. Because I had the volume up full the whole signal was disappearing. I noticed this by moving the volume pot while checking for a signal at the collector of 337. With the volume pot at zero it doesn't short any of the signal to ground so I saw full signal at the collector, and then dc removed signal after that cap.
Silly mistake really. I should have eliminated basic problems before getting the scope out. Anyway, I did learn a few things along the way.
Curiously, Y636 and SFT337's bases have a dc offset of around 7V. I didn't think this was normal. And the 25uF cap after Y636's emitter doesn't seem to block the dc. Presumably after that cap the dc is now coming through SFT337. But then the cap 25uF after 337's collector does block the dc and then the signal comes out to the volume pot. Interesting stuff.
Thanks for all the help!
The wiper of that volume pot went off to the jack - which was shorting the two terminals. So the signal was shorting to ground. Because I had the volume up full the whole signal was disappearing. I noticed this by moving the volume pot while checking for a signal at the collector of 337. With the volume pot at zero it doesn't short any of the signal to ground so I saw full signal at the collector, and then dc removed signal after that cap.
Silly mistake really. I should have eliminated basic problems before getting the scope out. Anyway, I did learn a few things along the way.
Curiously, Y636 and SFT337's bases have a dc offset of around 7V. I didn't think this was normal. And the 25uF cap after Y636's emitter doesn't seem to block the dc. Presumably after that cap the dc is now coming through SFT337. But then the cap 25uF after 337's collector does block the dc and then the signal comes out to the volume pot. Interesting stuff.
Thanks for all the help!