Hi Mike, The schematic for my Omni VI (563) shows R3 as 100 ohm and R4 as 1 k ohm. So as long as the 564 is the same, you have interpreted the ink blobs correctly. DE N6KB >I'd like to replace R3 and R4, the 1 turn pots on my #564's TX audio board, >The value >for R4 appears to be 1K, but the value for R3 is just a glop of ink. 100 >ohms, maybe? > >