[Drake] TR7, R7,RV75 issue

[jkerby]

Howdy,
 It took me about 12 years to finally get all the junk together for a TR7,
R7, RV75 station. It seems I have one more bug to get over. I've had the
station together for a year and lately it's developed a symptom I haven't
been able to trouble shoot. After being on a while the sensitivity and audio
of the R7 takes a ~10dB decrease slowly tapering off. A quick cycle of the
transmit relay in the TR7 brings it back.
 I removed the relay twice and have cleaned it. This did not cure the issue.
I have also tried the R7 and TR7 separately. Neither seem to be doing this
un-connected from one another. 73 de n4yu