luke_k90
Member
Hi All,
I decided to attempt recapping some of the boards on my TS-430 since it was exhibiting inconsistent Tx power and Rx sensitivity drastically shifting from band to band. I also cleaned all the relays on the filter unit and all contacts on the RF board, filter unit and final unit using contact cleaner spray.
The back section of the radio containing the filter unit and final unit I found rather difficult to work with - the last person to open it up had put in some additional cable ties and I ended up having to cut all the cable ties in the back to be able to tilt open and remove the PA and fan.
I tested the radio during the day after working on the filter unit - no issues (but also not much in the way of RF signals during the day here). Once I replaced the caps on the final unit I tested, this time at night, and was greeted with a lot of Rx noise.
The noise is a warbly rough static that is audible, although low and in background below 7Mhz. Beyond that it builds in volume until it is loudest around 10-13mhz, then drops lower again the further up the HF spectrum I tune.
Additionally:
- the noise disappears when I lower RF gain
- the noise drops for half a second when I flip the attenuator switch, before rising up again
- at its loudest, the noise can be almost completely quieted by strong AM signals ~10mhz
- noise is present, but filtered, in LSB, USB and CW modes.
- no noise is present when no antenna is attached.
I confirmed the noise is not occurring on other radios with the same antennas. I also did not replace all the cable tie I cut, as I thought I may need to open this section of the radio again before putting it back in operation.
This is the first time I have worked on a radio, I was nervous to attempt it and I knew there would be mistakes but it is a skill I want to develop. If anyone has suggestions on what the source of the noise might be I would appreciate it a lot. I know have provided very little to go off - I have a scope and DMM that I’ve used for work with processor and logic gate IC’s in 8-bit computing but never radios. I’d love to learn how to tackle troubleshooting radios so let me know where you think I should start.
I decided to attempt recapping some of the boards on my TS-430 since it was exhibiting inconsistent Tx power and Rx sensitivity drastically shifting from band to band. I also cleaned all the relays on the filter unit and all contacts on the RF board, filter unit and final unit using contact cleaner spray.
The back section of the radio containing the filter unit and final unit I found rather difficult to work with - the last person to open it up had put in some additional cable ties and I ended up having to cut all the cable ties in the back to be able to tilt open and remove the PA and fan.
I tested the radio during the day after working on the filter unit - no issues (but also not much in the way of RF signals during the day here). Once I replaced the caps on the final unit I tested, this time at night, and was greeted with a lot of Rx noise.
The noise is a warbly rough static that is audible, although low and in background below 7Mhz. Beyond that it builds in volume until it is loudest around 10-13mhz, then drops lower again the further up the HF spectrum I tune.
Additionally:
- the noise disappears when I lower RF gain
- the noise drops for half a second when I flip the attenuator switch, before rising up again
- at its loudest, the noise can be almost completely quieted by strong AM signals ~10mhz
- noise is present, but filtered, in LSB, USB and CW modes.
- no noise is present when no antenna is attached.
I confirmed the noise is not occurring on other radios with the same antennas. I also did not replace all the cable tie I cut, as I thought I may need to open this section of the radio again before putting it back in operation.
This is the first time I have worked on a radio, I was nervous to attempt it and I knew there would be mistakes but it is a skill I want to develop. If anyone has suggestions on what the source of the noise might be I would appreciate it a lot. I know have provided very little to go off - I have a scope and DMM that I’ve used for work with processor and logic gate IC’s in 8-bit computing but never radios. I’d love to learn how to tackle troubleshooting radios so let me know where you think I should start.
