Flex 3000 fan noise reduction

g4jnw

I would like to replace the fan in my flex 3000 - i have read stories about overheating after doing this but the computer market has moved quickly since they were first built, is it possible to reduce the noise from the fan by replacing it with another but yet still shift as much air so there is no overheating?  If so can someone give me a direct replacement model and make number as i don't want to alter the case as the case is in as new condition.

Tim - W4TME

Being a very small form factor 100W radio with minimal thermal mass, the fans have to move a lot of air to cool internal components.  The factory installed fans in the 3000 have a low noise rating in dB for the required airflow in CFM. You may be able to find a fan that is a few dB lower in volume, but that will not make the radio any quieter due to the volume of air being passed through the cooling plenum (that makes noise too).  Using fans that have a lower CFM rating will be a detriment to cooling the PA transistors and other TRX board components.

You also do not want to modify the case.  The air inputs at the front, draws air over other TRX board components cooling them too.  Punching or cutting holes in the top of the case will interrupt that air flow and degrade the overall cooling efficiency. 

Since the FLEX-3000 has no active user controls on it other than the power switch, I recommend that you move it to a location where the fan noise is not as objectionable.  When I was exclusively using the 3000 for operating and software testing,I placed it under my desk.  That reduced the ambient fan noise enough for me.  Wearing headphones helps too ;-) 

g4jnw

Thats fair enough will try that - i have 2 fans going one in the power supply for supplying the 3000 plus the 3000 one, my shack is particularly quiet as I'm using a laptop and its at the back of the house so i guess I'm more sensitive to noise.

Tim - W4TME

Understood. I know it can get a little loud when operating full duty cycle modes or having long QSOs. I remember one person put it in a home-made actively cooled anechoic chamber.

g4jnw

mine is noisy without transmitting i.e.; on receive haven't kicked it up to 100w yet!

Tim - W4TME

In that case you may have a fan that is failing.  You can contact Norbert at our Service Center in Germany.  He may be able to provide you some replacements (replace both at the same time).  They are not hard to install once you figure out how to get the cover off (flip it on its back and make sure you remove the nuts from the 1/4" connectors on the front.  The cover slides forward).  

g4jnw

trouble is i don't know how noisy they should be, it may be worth changing the fan can you email me his contact email please. I'm gm4jnw@gmail.com or can i just buy a replacement off the net, if so do you have size and spec i need, i presume they will be plug in computer type its just the flow of air etc i need

Tim - W4TME

You can contact Norbert at frs-service-eu@t-online.de or  (+49) 4356 1625.

They are plug-in type fans.  it is the dimensions and airflow that are important.  I don't ave that info off the top of my head; I'll try to get it for you.

g4jnw

Thanks would appreciate that and hold off emailing Norbert as i may be able to get an equivalent 

Tim - W4TME

It is a Dynatron p/n: DF126010_H
http://www.dynatron-corp.com/en/product_detail_1.aspx?cv=20-72-109&id=50&in=0

The important thing is the CFM rating.  it needs to be at least 24 CFM to compensate for the back pressure and provide adequate cooling.  And do not get one taller than 10mm.