The cheap Chinese copies of the Kenwood TCXO boards are rubbish, I bought and installed a superb TCXO from Mark Goldberg, W7MLG. The results are fantastic, my TS-590SG is now spot on
Kenwood SO-3 High Stability Oscillator – ATR
Ts-590s 15.6mhz High Stability Crystal Osc Module Compatible So-3 Tcxo - Instrument Parts & Accessories - AliExpress
KENWOOD TS-940 / TS-930 100WATT PA MODULE UNIT X56-1430-00 £99.99 - PicClick UK
OEM Bravo Professional Speaker Microphone for MultiPin
Ts-590s 15.6mhz High Stability Crystal Osc Module Compatible So-3 Tcxo - Instrument Parts & Accessories - AliExpress
My new Kenwood TS890 - WEARC News & Blog
Ts-590s 15.6mhz High Stability Crystal Osc Module Compatible So-3 Tcxo - Instrument Parts & Accessories - AliExpress