Kenwood TS-700SP antenna
to receive / transmit relay repair. 24 February 2023
The Kenwood TS-700SP radio exhibited an intermittent receive symptom when cycled between transmit and receive. The issue was identified as oxidization of the RL1 antenna to receive/transmit relay contacts on the receive side.
To address the problem, the RL1 relay was removed, disassembled, and the contacts were cleaned before being reinstated in the radio. This resulted in the resolution of the intermittent receiver fault. The relay contacts were carefully cleaned using contact cleaner and gloss paper to avoid damaging the silver coating on the contacts and to prevent any paper fibers that could potentially interfere with good electrical contact.
The RL1 relay, a miniature RF relay, is a SPDT, Fast Reed Switch with a 12-volt, 390Ω coil. It is manufactured by ATS, with part number CX-1051, and is currently difficult to obtain.
Figure
1. RL1 antenna to receive / transmit relay per the block diagram.
Figure
2. RL1 antenna to receive / transmit relay per the schematic
diagram.
Photo
1. RL1 antenna to receive / transmit relay
Photo
1. Relay contacts being cleaned with contact cleaner and gloss
paper.
Video
of the Kenwood TS-700SP antenna
to receive / transmit relay repair.
