Re: 2320 PA Modifications?

Clint Sharp <cjaysharp@...>

You could beg, borrow, buy a PWM compatible 4 wire CPU fan, they're very cheapo or even free if you find a scrap/defunct PC and are easier to control than 2 wire fans which can be unpredictable from one brand to another but you'd need a source of 12V added into the mix.


On Fri, 23 Oct 2020 at 10:32, Richard White <gi4doh@...> wrote:
I have both types of Nokia board and the screwed down component one is my 'active' one at the moment - it came with the original heatsink so was easier to package. It benefited from a bit of snowflaking too.
I use an Arduino Nano to read the onboard temperature sensor. I then control a 24V fan based on the temperature. At idle 20% is fine and the noise is low - there is always the PSU on/off switch if I am not going to be transmitting.
From a cold start this morning it was 5 minutes before the board got up to 24 degrees at which point the fan came on. I draw about 1.5 amps at 28V when idle.
Above 40 degrees the fan goes to full speed - more noise but the temperature doesn't increase by much more after that.
For those plagued by the nominal 10 ohm resistors in the bias chain that don't like the power on surge, 33 ohm 0402 seems to be working for me at the moment with now noticeable reduction in power out.
Note the fan isn't happy with PWM settings between 30% and 90%. I assume that is because of its inbuilt brushless controller not liking the on/off ratios. But the fan was cheap not a problem functionally..
Richard GI4DOH

Clint. M0UAW IO83

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