This is a simple modification that takes around 5 minutes but makes a big improvement to the already great TM-V71. The fan on this radio is very loud and runs at full speed from the moment you press the PTT then stays on for a few minutes after you release the PTT. This isn’t a problem in a mobile setting where there is usually more background noise but it is very loud when using the TM-V71 in a quiet home shack.
Just a few basic tools are needed along with two small pieces of heat shrink and a good upgraded fan. I use the Noctua NF-A4x10 which is on the more expensive side of the fan world but it’s well worth every penny.
Just remove the top of the radio, remove the existing fan, cut off the connector and solder onto the red and black leads from the new fan. Put it back together and enjoy the silence!
I just did this mod to my new TM-V71 and it works great, much quieter now. Thanks!
Matt,
Thanks for pointing out the Noctua fan. I have 2 TM-V71As (base and mobile). The newer one developed a bearing-like noise just after the one-year warranty expired and it became even noisier, but Kenwood replaced it under warranty.
Their fans are noisy regardless and I am considering your mod, but I am curious as to the CFM of the original vs Noctua fans. I don’t know the CFM of the original, but the Noctua runs around 4.83CFM (8.2m³/h). I suspect much of the noise difference may be due to design, but possibly some because of differing amounts of air moved. Did you happen to check that out?
The original Kenwood one I removed was rated at 4.68CFM according to the label. I find the Noctua much better and far less noise! They are not the cheapest but well worth it in my opinion.
Thanks Matt. Given that the Noctua fan moves slightly more air and produces less noise, I have ordered 3 of them, 1 for each of my 2 TM-V71s, and one to improve the final cooling on a uBITX I will be ‘assembling this coming fall (too busy with friend and family visiting during the summer).
Is it this one?:
https://noctua.at/en/products/fan/nf-a4x10-flx
https://amzn.to/2LB75YH (from Amazon)
These say “FLX” in the name and you make no mention of that.
Thanks,
Al
Hello Matt, I have purchased one of the last TM-V71 produced, with the original Nidec fan. I would like to install a Noctua. Seeing their site I noticed they have two 12v. models, the
NF-A4x10 PWM : https://noctua.at/en/products/fan/nf-a4x10-pwm/specification
and the
NF-A4x10 FLX : https://noctua.at/en/products/fan/nf-a4x10-flx/specification
Wich one do you think it’s the most appropriate?
And, should I install the Low-Noise Adaptor (L.N.A.)?
Thanks, Helder Maia, CT1EXJ
Hi Helder.
I used the FLX version.
Matt
No problem. It would be good if you can post back with your opinion of them. I have just changed the fan on another TM-D710 and a TM-D700. Both work great!
Hi Matt!
Have just completed your advice and there was a much lower noise level after modification. Thanks a lot!
Erling LA5RIA
Hi Matt,
Purcased Noctura FLX fan from Company “Computer Xtreme” in Germany via eBay.
I just did the fan modification, very big improvement! Many thanks for your advice!
Erling LA5RIA
Hi, Matt. I recently acquired a TM-D700A that has some occasional and minor bearing noise. The current fan runs quiet 98% of the time, but I wanted to just fix it before burying the radio under the seat of my truck. I was looking for some guidance on the process and what fan to use when I came across this page. Good info! I was also going to ask if this fan mod would work on the TM-D700A, but saw your note that you’ve already done it. Just wanted to thank you for posting this write-up.
Hi Andy and thank you for your comment. I’m glad my post was helpful.
It was. Very. The new fan has been installed for awhile now. It was so quiet that at first I had to turn the radio around to see if it was actually spinning. It is as near to silent as a fan can be, but still moves sufficient air. This is the fan Kenwood should have used form the start.
Great, I’ve tested many fans and the Noctua and top notch. I run them on pretty much all of my radios now. One of the first mods I do when they are out of warranty! I’m looking at fitting one to a Elecraft KPA500 amplifier next.
THANKS for the info! Works GREAT! Running rig as “base” unit is a quite shack…
No problem. I’m happy it helped!
How did you remove thick insulation that comes on the fan red-black-yellow leads. If you cut it, does it just slide off? Do I have to strip it? Any tips on how to do this?
How many inches should I leave?
I don’t have shrink wrap… will electrical tape wrapping work OK?
The standard ‘insulation’ is actually a woven sheath that just slides over the wires. It’s easy to pull off once you have cut the original plug off. The length you decide to leave will depend on how you want to route the wires inside the radio. Electrical tape will work fine but heat shrink is much neater. Hole that helps!
Wow. Thanks for the quick reply. I’ve not soldered anything for 50 years… but did a lot of it as a teen and first licensed. I’m leaving for Harbor Freight to buy “helping hands” and some heat shrink. (I’ll try it with lighter or hair drier.) I bought a Weller iron and solder at Home Depot earlier. I hope I don’t screw this up!!
Job is done, the fan works great… I can’t hardly hear it. What I huge difference in sound. It does not feel like it puts out a lot of air but once I get on the radio for an extensive length of time I’ll see if the unit gets really hot underneath.
Thanks so much for posting this and answering questions. You did a good service and will get good radio-karma for it!
I had forgotten how the red and black fan wires got inside the body of the radio. I could not tell from your pix above. I just fed them underneath the rubber power-cord grommet. I didn’t see another way in.
Great work Al. I’ve put my 710 through some tough usage and not had any issues with overheating. It’s difficult to see from the images but the power for the fan routes through the back where the fan attaches. I’ll see if I can get time to take the top off the radio and add some better images.
After looking at more pictures of the fan I think I see how the leads should have been brought into the body of the radio… through the notch in the corner. It wasn’t apparent to me that the wires could be fed through it into the radio. So I just brought them in under the rubber grommet of the power supply.
To fix it I’d have to take the radio a part, unsolder the wires, feed them through the hole and then re-solder. Do you think it is necessary? I’ll do it if you think so.
If it works and you are happy then just leave it as it is!
Hello Matt, finally, today I changed the original fan of the Kenwood V-71 and installed a Noctua. It was really easy, this PWM model has 4 wires, I connected the + and – only, not a big diference from the FLX version. The item came with 2 connectors, really good design, that maintain contact after being tightened with pliers, it was not necessary to weld.
Thanks for your great support, 73, Helder Maia
CT1EXJ
About to do your modification….. fan should arrive tomorrow. I can’t really tell what is the direction of the fan’s air flow. I believe it is from outside to inside. Is this correct? Thanks for the write up and the pictures.
Joel
Hi Joel. The fan pulls air through the radio and pushes it away. The air should be flowing away from the radio. I hope that helps.
Thanks for the quick reply… I will set it up to exhaust the warm air out from the radio. I do like the Noctua fans and have them in all of my computer setups. I was part of a FLDigi net this evening. With short bursts of 100% duty cycle (even at low power) the fan noise was drowning out the subsequent conversations. Looking forward to the quiet. Thanks again! Joel
As I remember there is only one label on the fan and that goes on the outside of the radio… meaning that you can see it when looking at the back of the radio. If you can’t see the label, you have it wrong.
Took about 30 min to complete just because I was being slow and careful. What took the most time was trying to get the old fan connector off without breaking the entire connection (I have a known impairment when it comes to removing small connectors). I finally gave up and clipped the wire at the base of the old fan, adjusted the length of the Noctua wire and used the enclosed quick connectors and was done. Actually a very easy project. Just completed net tonight. I needed a flashlight to check that the fan was actually running – it is that quiet. Thanks again for the pictures and instructions. The V71a is now a perfect base station radio.
I have this radio and get an electronic whirring sound which is detectable in my transmit audio. Could it be a defective fan? I guess I could unplug it for a sec and test. Just wondering if anyone else experienced this.
Hi Mike. It could be the fan generating RF noise. Like you say, the easy way to check is to unplug it and see if the noise has gone.
I love the fact that I can come back to this page and it’s still valid. I did this mod to my TM-D710 a few years ago with the specified fan, and then recently purchased a TM-V71 and it is just as loud as my old TM-D710.. So I googled the issue and this page came back up. I then followed the link to the fan and low and behold, the fan I purchased years ago is still available and the amazon page even says that I purchased it back then. 🙂 Thanks for the great page.
Thanks for the feedback. It’s always great to know my random posts help!
I found your information about fans while searching for a replacement for my TM-D700A fan. It’s a similar arrangement but not quite exactly the same. I found that the fan is mounted in a different way. It’s held on by a plastic frame that clips into the metal heat sink of the radio. The fan is screwed into the back side of the plastic frame. The problem is that the original fan has countersunk holes to accommodate small locating protrusions at the mounting hole sites of the plastic frame. While the new fan has countersunk mounting holes, they are on the wrong side of the fan. I had to drill out the fan mounting holes on the non-countersunk side to get the fan to mount facing the proper direction. But after that, it all went smoothly. And I concur with everyone else – you can’t hear it when it’s operating. I had to grab a flashlight to check it. Thanks for enlightening us.
Here we are in 2024 replacing the fan on a NOS V71A I stumbled across dirt cheap in Dayton. Ordered the fan yesterday & it’s already installed today. Currently $13.95 on Amazon. Mine is operating as a DigiGate & the stock fan had to go. I personally game/build & Nactua ‘s are the only fans I use in everything. My FT-710 has one also. Thanks for the information on the simple swap.