My 91 940 has a CR-814, and I really enjoy the FM performance.

Over the past 10 weeks, the FM output has deteriorated, and now intermittently falls into 3 categories:

Great FM signal.
No FM signal.
About 1/3 FM signal and 2/3 rumble. (This can be varied by pressing on the exterior of the unit.)

(AM signal and cassette use are unaffected.)

After removing the radio, I pulled off the plastic head, and top & bottom metal covers.

The faulty part is a steel box, found inside the right-side of the case. It's about 3/8"w x 2"h x 3"d, with PC board on its left side (all looking from the front). It's connected electrically to the topmost PC board, and also physically soldered to a tab on the case metal side. When I flex that side or press this little steel box, the FM signal goes in and out as described above. When the signal is out, and I connect a probe from this box to the radio's ground, there is no change.

All external connections visible on this little box look fine. And, soldering isn't my longest suit, so the less of that the better.

Any ideas?