As I open this guy up I see a couple things to worry about. A few bad solder joints and a loose ground connection. Those got done right away. Also, noise from the motor would find its way into the signal path. That turned out to be the condition of the tape. With new tape and cleaned up tape heads, it no longer appeared on the signal path. After that came the modifications. The output cable was replaced for a jack and a grounded power cord was installed.

One of the few bad wire joints(look at the brown wire).

Loose ground wire!

After those got done the modifications began.

Output cable and power cord before:


And that’s it, done!