Kenwood TH-K4AT Service Manual

Also see for TH-K4AT: Instruction manual Instruction manual Service manual

TH-K4AT/K4E3DISASSEMBLY FOR REPAIRSoldering the antenna terminal1. With the shield cover removed from the antenna terminalsection, install two screws on the PC board and bring thePC board into contact with the chassis (z).2. Solder the antenna terminal with a soldering iron (x).3. Remove the two screws installed in step 1 above, and installthe two screws again on the PC board together with theshield cover (c).Replacing the final FET (Q12)1. Remove the two screws holding the shield cover of thefinal FET section (z).2. Remove solder from the shield cover completely with asolder absorber.3. Remove the shield cover (x).zxczx4. Apply the tips of soldering irons to all the four pins of the finalFET at the same time (c), heat them sufficiently, and removethe final FET (v). (Two persons should be required to do this.)5. Remove all PC boards from the chassis.6. Confirm that there is no space between the radiation plateinstalled on the foil side of the TX-RX PC board (TX-RX unitA/3) and the PC board (b). If there is any space betweenthe radiation plate and PC board, eliminate it by applyingthe tip of the soldering iron to the radiation plate.7. Apply the tip of the soldering iron to the installation side of theradiation plate of the TX-RX PC board, put a little amount ofsolder to the radiation plate that is seen through a square holein the final FET installation section and melt the solder (n).8. When the solder in step 7 is melted, place the final FET onthe PC board by aligning it with the silk of the final FETinstallation section of the PC board (m).9. Release the soldering iron and confirm that the final FETand radiation plate have been soldered.10. Solder the four pins of the final FET with the soldering iron.11. Install all the PC boards.12. Reinstall the shield cover removed in step 3 above in itsoriginal position and install two screws.13. Solder the shield cover to the PC board.14. Install the chassis on the case assembly and assemble them.15. Readjust transmission power.Note: Since the FET is sensitive to static electricity, alwayswear a grounding band. Use a highly insulated ceramicheater solder iron.Radiation plateTX-RX PC boardbcvmnThis illustration isM2 type.