Author: Kenwood Communication, inc.
Service Bulletin no. 1058 (6 May 1994)
Some early versions of the TM-566A/E have been discovered with a bad solder connection at the final module pin diode, D601. If the impedance of this devices is too low, the power consumption for this devices goes up. This increased power consumption might cause excessive heating of the solder connections, and may result in a failure of the connection(s) after long FM transmission.
On the TX/RX unit replace diode D601 with a UM9401, change R606 to 100 ohm, change C623 to 5 pF, and C624 to 12 pF. After replacing these parts, readjust the NULL and Protection circuit using the procedure provided in the service manual.
Qty Description Part No. Circuit Description
1 Pin diode UM9401 D601
1 100 ohm chip resistor RS14DB3A101J R606
1 5 pF chip capacitor CM73F2H050D C623
1 6 pF chip capacitor CM73F2H060D C624
Time required for this modification is 60 minutes or less.