[Kenwood] TS-440S Base band noise drops

[W0rw at aol.com]

My TS-440S base band noise drops off after a few minutes of warm up.
Rx is connected to my  HP8640B sig generator.
The sensitivity isn't effected too much but the "S" and background noise
drops 10dB.
It is very intermittent but not sensitive to shock, Yet.
Maybe sensitive to cold/hot temps.
No Band changes, Mode or Filter changes or other controls effect it.
Still troubleshooting. i am going to be looking for cracked solder joints
under potted subassemblies for sure.
Has anyone seen this before ?
Paul  w0rw