I own 6 HM-14 Microphones. 4 are working 100%. One has DTMF but NO voice. One has good voice, but NO DTMF. This tells me that the switches, cables and connectors are not suspect. Anyone have a source for the schematics? Thanks. Merry Christmas. Mike - KD9KC. M.A.R.I.E. El Paso, Tx. www.w5dpd.org