Here is a strange one. All my Shure lav mics work OK with my UR1 transmitter. But several lav mics that are European do not. I get hum, buzz, and intermittent operation. Any ideas?
On rare occasions, the UR1 or the UR1M-LEMO3 has exhibited a ground connection issue. The mic connector, TQG or LEMO, is not solidly connected to the transmitter chassis ground. Some mics rely upon this chassis ground connection in place of a pin 1 connection. A field diagnostic step is to loosen the mic connector nut, scrape away any excess paint or corrosion, and re-tighten the nut to ensure the ground connection between the mic connector and the transmitter chassis.