Thursday 9 November 2023


There's been some discussion on various platforms suggesting concern over the FX-4CR's operating temperature, even though I've never heard of anyone suffering any sort of failure, so I do believe that these concerns might be a little irrational (but that statement might come back to bite me, lol).

Having said that, I've been guilty of similar worries with my Expert Electronics ColibriNano, which runs incredibly hot! I was so concerned that I wrote to EE seeking some reassurance and I was told very clearly that the unit is designed to cope with those sort of temperatures. Nevertheless, I decided for the sake of longevity, I would fit some heatsinks and after completing the task, I felt much better. The ColibriNano ran cooler to the touch.

So with that little success, I thought I'd do the same to my FX-4CR. Opening up the case, you can see that there's a large aluminium heatsink plate in the middle of the radio and the high-temperature components press directly against it to help dissipate the heat.

The hottest part of the radio is the very top (and slightly to the right side). This makes sense when you consider the location of the PA and so I decided to attach my heatsink there. It was a very simple matter to remove the top and rear covers, allowing me to apply a bead of thermal-paste to the internal heatsink. The parts circled in yellow are the areas requiring the most cooling.

With that job done, it was just a case of reassembling the radio and then applying the external finned heatsinks. I applied a couple of dabs of thermal-paste to the underside before spotting with high quality superglue, being careful not to get the glue on the rear edge (or I'd effectively be gluing on the rear cover, lol).

When the job was done, I ran the radio for 30 minutes or more, repeatedly sending a CW message into a dummy load at 20W. At the end of it, the radio felt pretty warm to the touch but there was nothing to worry about at all, so I'm 100% happy that there would be no issues with overheating at the power levels I normally work at.

I guess time will tell.

73, Tom, M7MCQ.


John AE5X said...

Hello Tom,

I'm hopeful that this rig will mature into what I had oped it would be initially. Had 2 early versions, sent them both back due to (1) connectivity issues (with PC & Mac) that prevented fw updates and (2) multiple CW keying issues (omitted first dits &/or lack of sidetone. Then I read about intermittent, but infrequent, band changes when keying the rig on CW.

A few owners have informed me that these issues are now corrected, but none of them are CW ops so I remain a bit skeptical.

Thanks for your review - it's been evident from Day 1 that Yu wants to make this a properly functioning radio and I remain optimistic that that will eventually be the case for us CW ops.


MadDogMcQ said...

Hi John, thanks for the visit - much appreciate your knowledge and expertise around here. I guess all early production models run into problems, but hopefully most of the issues are sorted by now. I am aware that some CW ops are still experiencing some band-jumps but the cause appears to have been found and the fix can be carried out easily by owners.

Hope you're keeping well.

73, Tom, M7MCQ.