Yaesu: Yaesu ftm-400 clicking issue

[nv2m]

Hello all,
I purchased a yaesu ftm-400. I hear this strange noise coming from the radio unit when I transmit. It sounds like a series of relays chattering. the clicking doesn't have any kind of defined pattern. It only happens on transmit, and the condition doesn't happen every time I transmit. When I do hear it, it can be just a few in succession, or sometimes a second or so of this grinding going on. Currently testing this on a bench on UHF, power output currently set to low and I'm measuring around 3.7w output, SWR around 1.6. Antenna is a mobile mag mount sitting a few feet behind me on a metal filing cabinet. PSU is a linear rated at 10w but should be sufficient for low power transmit testing.

Any thoughts on what this noise is and what could be causing it?

Thank you

 

[KE5MC]

10 Watt ps at 13.8 volts is less than 1 amp. Receiving ok but transmitting the radio or ps is not going to be happy. The 400 is a bit of a power hog.

 

[nv2m]

My bad, typo. That was supposed to be 10A power supply

 

[WA0CBW]

Is the clicking coming from the radio speaker or from the chassis itself?

 

[nv2m]

I think it is coming from the chassis itself. I'm going to do more testing today and see if I can verify more precisely where it comes from.

 

[AK9R]

The Yaesu FTM-300D has a relay that clicks when you transmit on UHF, but not VHF. I wonder if the FTM-400D has the same sort of arrangement.

 

[MTS2000des]

Yes as does the FTM-200, 300 and 400, all the way back to the FTM-100. There is a relay that is activated when transmitting on UHF. This is not a malfunction, just the way these radios were made.

 

[nv2m]

After much troubleshooting all of the external stuff with ham friends of mine, the issue was narrowed down to an internal relay. After some probing and gentle heating/cooling of components looking for reproducible failures, it looks like the relay finally went and we were able to confirm the part failure. It was a bit strange, but the RL1503 relay is shot now and was the source of the clicking noise I reported above. It was a completely intermittent issue going long periods of time before it would happen.

Anyway Yaesu will still repair the FTM-400xdr radio, so its going there to confirm and fix. It will be a few weeks, when I get back the final diagnosis I'll post back here.