SB-045 TR-7600/7625 Audio Tone on TX 8-10-79 Some TR-7600/7625 users report a low background tone during TX, especially noticable at full quieting by the receiving station. On the PLL unit X50-1580-00, change: L18 from 22 uH to 33 uH C61 from 22 pF to 33 pF C60 from 22 pF to 10 pF C42 from 22 pF to 39 pF, or bridge 18pf across foil side and leave original C42 in place. No adjustment is necessary. New part: L18 33uH L40-3301-03 Please annotate your service manual. JEB/yn (c) 8979TKC