The Dell 3070 micro is nice small yet powerful PC to have on the desk. The blue cradle can hold a Harddisk or SSD with a SATA connector, but the motherboard can be upgraded with a M2 SSD , size 2242 or 2280 as well. I removed the SATA disk and installed a Crucial CT500P5SSD8 512 GB M2 SSD. When making a full backup to an external SSD drive, it turned out, that the Crucial M2 SSD became quite hot , that is, more than 80 degree Celsius at the position, indicated at the red circle at the rightmost picture. At that temperature the SSD makes a thermal shutdown, and the PC stops !.To avoid the thermal shutdown, I used the empty cradle to hold a NSTECH PAAD16010SM tangential fan to remove the air from the hot spot area. The test setup to measure the temperature at the running fan during a full backup included a 5 V power supply and a Fluke meter with thermo coupler ( brown wire ). Fan wiring: black is GND and blue is connected to 5 V. This fan is rated at 12 V but runs ( slower of course) noiseless at 5 V.Measurement is made at 23 degree Celsius room temperature. The fan distributes the heat in the case, and the temperature controlled CPU fan moves the hot air to the rear side.
In case a microcontroller based temperature controller is to be used, a fan tacho open collector output is provided. To use the tacho signal a pull-up resistor of 4K7 is used, and I made the following measurements:
Tacho frequency: 58 Hz at 5V supply, and 133 Hz at 12V supply.