Here's the six (6) transistor version of your radio:https://samswebsite.com/en/photofact/se ... del/PTR62B
And a really good webpage on how to restore one:http://www.transistor.org/restoration/restoration1.html
I'll have to check my Photofact collection of schematics to see if I can find it under another name.
You can check to see if your LO is really dropping out by tuning in the LO signal with another radio.
~ Mitch ~