Kenwood TS-570D User Manual - Page 70

16 MAINTENANCE INTERNAL ADJUSTMENTS REFERENCE FREQUENCY CALIBRATION Note: ◆ The transceiver is adjusted at the factory prior to shipping. Unless necessary, DO NOT perform this adjustment. ◆ If you have installed the optional SO-2 unit, you cannot perform this adjustment. 1 Set the following on the transceiver: • Mode: CW • AF control: Center • Menu No. 20 (CW RX pitch): 800 Hz • IF SHIFT control: Center • Receive bandwidth {page 38}: 600 Hz • RIT function: OFF • Break-in function (VOX): OFF 2 Remove the bottom case (8 screws) from the transceiver. 3 Remove the protective cover installed on the PC board (6 screws). 6 Adjust the TC500 trimmer to minimize the frequency difference between the received 800 Hz tone and the 800 Hz sidetone. TC500 7 Re-install the protective cover on the PC board (6 screws). 8 Re-install the bottom case (8 screws). ACCESSING THE INTERNAL FUSE 1 Remove the top case (8 screws) from the transceiver. 4 Tune in a standard frequency station such as WWV or WWVH at, for example, 10.000 or 15.000 MHz. • Adjust the Tuning control so that the display reads the exact frequency of the station. • You should hear a beat tone of approximately 800 Hz. • For 800 Hz: faf = (fdisplay/20.000 x ∆freference) + 800 Hz where ∆freference is the shift from the 20 MHz reference frequency 5 Close your CW key and you will hear a transmit sidetone of approximately 800 Hz. • This sidetone produces a double beat tone when it combines with the received signal. • Adjust the AF control to hear the double beat clearly. • For 800 Hz: fsidetone = 800 Hz±50 ppm (= 800 ±0.04 Hz) where ∆freference is the shift from the 20 MHz reference frequency 2 Remove the 12 screws that fasten the inner cover to the chassis. 3 Open the inner cover. • Be careful not to damage the speaker cable connected to the PC board. Fuse (4A) 64