DPO7054

[phoenix1988]

Hello, I have a question about the DPO7054 oscilloscope. When the device is turned on, there are 2 fans on the left side panel, only 1 works. I measured the voltage, it is only on 1 connector. Question: is ventilation implemented here so that one fan works first, and when the temperature increases, both, or is my oscilloscope not working properly? Thanks

[inse]

As far as I remember the fans are speed controlled, so the rpm pulses would also be monitored.
Is it possible to check the fan speed in the BIOS?

[phoenix1988]

D.h beide Fans sollen funktionieren mit verschiedene Temperatur (je  mehr die Temperatur, desto größer Geschwindigkeit  haben Fans) , oder eins fan bei  kleine Temperatur beide bei höher Temperatur.

[mikehank]

Both fans are controlled separately bi the PowerPC board.  These fans pull air up though the acquisition board from the bottom to cool the board.  Both will need to be working for reliability.
On the PowerPC board there are a couple of transistors near the fans I can't remember the reference designators but these commonly cause fan issues.

[inse]

I just have checked with the DPO7054 here at work: only the top fan spins up at startup.

[mikehank]

The fan driver issue is pretty common.  Several reasons exist why the control circuit gets in trouble..

1) if the covers have been removed with the feet.  If a DPO7K does not have proper bottom ventilation it will overdrive the fans to keep it cool. 

2)1 fan does go out the second will try to keep up damaging the circuit

3)one of the ASIC's on the acquisition board has a broken ball reporting an over temp condition or no status condition.  Usually this issue involves a DEMUX.

4)build up of dust and crap

I have seen this issue dozens of times in the past super common.