I have a Yaesu FT 227R in very good condition with no signs of having been altered or repaired. It worked fine in sending and receiving, but on one occasion after finishing a QSO it continued in sending. Now when I turn it on it starts broadcasting immediately. When I turn it off, the relay turns off too. I would appreciate any clue to resolve this malfunction. Thanks
Yaesu: Yaesu FT 227R
- Thread starter ct1epq
- Start date
- Status
I wonder if a transmit/receive relay is sticking.
techman210
Member
The relay is likely not the problem.
If, when it's turned on, it's generating RF, and you said the relay is working, and the TX light on the radio is on, then it's likely something in the PTT circuit in the radio.
Unplug the microphone and see if it does the same thing.
Then, remove that accessory plug at the rear of the radio. You will lose RX audio, but does it still transmit?
After that, open the radio and see if there is anything metallic that fell behind those connectors.
Use a multimeter and see if the PTT line is shorted to ground at the microphone connector.
And lastly, get a manual or schematic, and follow the PTT line through the radio. There is likely something shorted between PTT and ground (mostly capacitors and transistors) that has gone bad.
It's a very old radio, but that makes it easier to repair and diagnose.
If, when it's turned on, it's generating RF, and you said the relay is working, and the TX light on the radio is on, then it's likely something in the PTT circuit in the radio.
Unplug the microphone and see if it does the same thing.
Then, remove that accessory plug at the rear of the radio. You will lose RX audio, but does it still transmit?
After that, open the radio and see if there is anything metallic that fell behind those connectors.
Use a multimeter and see if the PTT line is shorted to ground at the microphone connector.
And lastly, get a manual or schematic, and follow the PTT line through the radio. There is likely something shorted between PTT and ground (mostly capacitors and transistors) that has gone bad.
It's a very old radio, but that makes it easier to repair and diagnose.
Thanks for your reply.
Unplug the microphone and see if it does the same thing. ( yes on air always )
Then, remove that accessory plug at the rear of the radio. You will lose RX audio, but does it still transmit? ( yes always on air with no reception)
After that, open the radio and see if there is anything metallic that fell behind those connectors. ( nothing behind the connectors)
Use a multimeter and see if the PTT line is shorted to ground at the microphone connector. ( yes lower right mic pin is shorted to ground)
And lastly, get a manual or schematic, and follow the PTT line through the radio. There is likely something shorted between PTT and ground (mostly capacitors and transistors) that has gone bad. ( I will do it)
Best regards
Rui
Unplug the microphone and see if it does the same thing. ( yes on air always )
Then, remove that accessory plug at the rear of the radio. You will lose RX audio, but does it still transmit? ( yes always on air with no reception)
After that, open the radio and see if there is anything metallic that fell behind those connectors. ( nothing behind the connectors)
Use a multimeter and see if the PTT line is shorted to ground at the microphone connector. ( yes lower right mic pin is shorted to ground)
And lastly, get a manual or schematic, and follow the PTT line through the radio. There is likely something shorted between PTT and ground (mostly capacitors and transistors) that has gone bad. ( I will do it)
Best regards
Rui
- Status
