Elecraft K3 fans noise & FP high temp cure - Part I. (Intro)

Hi all,

after 7 yrs of daily operation of my K3 the fans sounds noisy. Even the rattling on low speeds (FAN1 mode) is noticeable and its getting me bothered. I asked Elecraft service for their kind help and they immediately offered me the replacement. So it was an excellent after sale service support, no complaint at all and I am waiting for arrival of the new fans to be replaced. 

The links for fans noise threats on Elecraft list:
http://elecraft.365791.n2.nabble.com/K3-Fan-noise-cure-td7606186.html
http://elecraft.365791.n2.nabble.com/K3-K3-fan-noise-part-XXLIV-td5091127.html

At the same time I realized that my K3 after huge upgrade and now fully loaded is quite hot even in idle (RX mode). The temperature sensors in machine does not reporting any oddities and the PA/FP temp is stabilized between 38-40C in RX idle when the FAN1 speed is selected but...

When I am touching the cabinet's side it is quite hot as same as the right side of the front panel. The main reason is that 5V and 8V voltage stabilizators located on the right side close to FP are using the cabinet as heatsink! So I started to thinking about more CFM powerfull and even quieter fan which looks like very good upgrade option solving both issues together.

The link for Noctua fans replacement threat on Elecraft list: http://elecraft.365791.n2.nabble.com/K3-Fan-Replacement-td7592075.html#a7592266


An early K3 machines fans version was an Elina HDF6015L-12LB by Inaba Denki Sangyo, Japan. 

 
Specs:
Airflow: 10.5 cmf
Noise: 21 dB
Speed: 2800 RPM
Static Pressure: 1.5mm
Current: 75 mA http://www.farnell.com/datasheets/1600097.pdf


Later K3 machines are equipped with fans UTEC AT6015L-12L2B-ND2 or ND5 by United Thermal Engineering Corp., Japan/Taiwan/China.

 

Specs:
Airflow: 15.4 cmf at 24.8db
Noise: 24.8
Speed: 3000 RPM (at 12v)
Static Pressure: 2.21mm Current: 100 mA
http://www.utecusa.com/products/pdffiles/pid_1-45-152_%28SPEC%29AT6015L-12L2B%20ND1%2812-22-08%29.pdf
http://usquarecorp.com/products/pdffiles/pid_1-45-152_(SPEC)AT6015L-12L2B%20ND1(12-22-08).pdf

According to informations collected by Joe, KB8AP it looks like the Elina fans were used on earlier K3 machines with serial numbers <900 or so which is my case also (#778).


New possible replacement fan type is Noctua NF-A6x25 FLX by Noctua, Austria (probably it's not EU production also)

Specs:
Airflow: 17CFM (29.2 m3h converted to cfm)
Noise: 19.3db
Speed: 3000 RPM (at 12 v)
Static Pressure: 2.18 mm Cutent: 120 mA (.12 A)
http://www.noctua.at/pdf/infosheets/noctua_nf_a6x25_flx_datasheet_en.pdf
http://www.noctua.at/pdf/manuals/noctua_nf_a6x25_flx_manual_en.pdf

The "6" number means 60mm size, "25" means 25mm tickness and FLX means Flexibility as fan can be fine-tuned for superior airflow or maximum quietness.

The link for Noctua supplier: http://www.newegg.com/Product/Product.aspx?Item=N82E16835608032

The link for Noctua manufacturer: http://www.noctua.at/main.php?show=productview&products_id=48&lng=en


I am thinking about the replacement and I am collecting as much as possible reviews or experiences from current users.


73 - Petr, OK1RP