2018-08-12 Making the HP DPS-700GB power supply less noisy 1 month ago
The HP DPS-700 GB power supply adapted to feed the linear amplifier has no own internal fans so I connected a recycled 50mm PC fan. Which runs at full speed which is a lot of noise. I ordered a 12 volt fan control module on-line so it can run slower and keep the noise down a bit. I'll probably replace the current fan with an 80mm PC fan and set a low minimum speed. The air has to move as the power supply has no internal fans and is quite good at a thermal shutdown. But as long as things don't get warm it would be nice to reduce the noise as this was very noisy. Update 2018-08-24: The fan control arrived and I replaced the 50mm fan with an 80mm fan too to keep the noise to a reasonable level. Now the power supply is not as noisy. Update 2018-08-25: And transmitting on the 10 meter band in RTTY makes the fan stop completely. I guess the strong signals nearby interfere with the pulse width modulation that regulates the fan. This will need to be fixed some way.