JUMA Amateur Radio Forum

JUMA PA1000, Please a hysteresis in the fan routine, now that temps go up my amp sits idle at about 30 to 31 degree, this means the fan keeps switching on/off all the time, every second or so.
The fan is always very nervous on the JUMA PA1000, personally i would like a more steady curve not changing speed with every degree

I had the same problem with the PA-100D. When I redesigned its firmware I included 2C worth of hysteresis, and this completely fixed this issue. Perhaps in the next update this could be included.

Hello Marcel,

You are right, there is currently no hysteresis in the fan ON/OFF control which can be annoying in certain ambient temperature.
We have now added a hysteresis and a new firmware will be available soon.

Additionally the main fan can be replaced with a silent model, see the instructions here www.jumaradio.com/juma-pa1000/Fan-repla ... nstruction

73 Matti OH7SV

Good news,

New firmware version v1.34 has been released now.
Hysteresis added to the fan control. Fan will be ON at 33ºC during warming and OFF at 30ºC during cooling to avoid frequent fan re-starting.

You can download and install the new firmware from here www.jumaradio.com/juma-pa1000/JUMA-PA10 ... mming.html

73 Matti OH7SV

Thank you very much, flashed the firmware into the PA1000 and are now waiting for ~30 degrees ambient temperature.

Excellent Marcel,

Did you notice the silent fan modification www.jumaradio.com/juma-pa1000/Fan-repla ... nstruction

Matti OH7SV

Matti,

i did see the fan modification, and did this this modification two years ago ,
we had some contact about that.

And as for modifications, i did an other one. I a made an switch in the front of the amp as i can not easily reach the backside to switch it on/off.

Ok Marcel,

You mains switch modification looks good and I understand your point. I have kept my JUMA PA1000 always ON for years because it consumes only abt 5W in stand-by.

Matti OH7SV