[Kenwood] SM220 help & schematic wanted

[Martin Sole]

Folks,

I've got an SM220 with an annoying problem. Seems to be fine when it's
cold but once it warms up the trace dims, and then finally just
disappears.

Any ideas?

Would also like a schematic to help try and figure this one out. I've
looked at all the usual on-line sources, dk.mods, krasnodar, bama etc
but nothing in the way of an SM220 schematic or manual. Wonder if anyone
has some info they could email me. Greatly appreciated.

73's de Martin, HS0/G4UQF
Bangkok