Modifications for the Kenwood TH-47


19-07-1998 TH-47A Mods for ext frq

1. Remove battery and antenna.
   
   
2. Remove case as follows: Remove volume,squelch and tuning knobs by pulling straight off.Remove shaft nuts using needle nose pliers or other such tool.Remove 4 screws from the case.NOTE: Do not remove the 2 screws that are on either side of battery release latch.Lift plasctic top from radio while separating the radio halves.
   
   
3. Open the radio up like a book and place on work surface.
   
   
4. Cut or unsolder green wire loop on the control board.
   
   
5. Reassemble radio,Reset microprocessor.
   
   

Radio will cover 400-470 MHZ.While scanning,a beeping sound will be heard at the band edges indicating PLL unlock condition.To eliminate this annoyance:

1. Open up radio as indicated above.
   
   
2. Lift up microprocessor IC303 leg # 62(This is the bottom microproccessor) (Third leg on left side from the bottom)This should be done only by those comfortable working with SMT components.
   
   
3. reassemble radio.

Radio will now cover 400-470 MHZ RCV/XMIT with no annoying beeps during scanning.Leg # 62 is the UL input to the microprocessor to tell it that an unlock condition is ocurring.With no input,the Microprocessor thinks that the radio is always locked,and no error beeps will sound.This MOD also allows XMIT,but that is the price you have to pay :-)
I have done this MOD to my radio with no ill effects.This MOD should also work on the TH-27A.