Before i forget:
That Digital Corp 48 V supply shown in one of the photos has a terrible hot spot. The 2x 330uF 63V rectifier caps run extremely hot, since they are mounted dense with three 2K resistors needed for stability with light loads. I took the resistors away and mounted them a little further above the unused area of the board. Now the two caps still get heat from the nearby inductor, but they run at about 60 or 70°C and should last a little longer.
Regards, Dieter
Yes, indeed, this module eFOA306-148 operates in dangerous thermal mode. Only below him is a small gap through which a small airflow is carried out for cooling.
I had to repair this module, as well as one Cherokee QB4548A.
In accordance with my measurements, SDA6020 power consumption 630W, while SDA6000 - 450W, WP7300A - 430W.
i'm thinking about my mod 65W to 95W cpu, thats 2A+ addition, not to mention additional fans and liquid pump (small one) i'm adding to it. anyway i'm ordering 2X 0.22A 65CFM fan just for experimentation if possible to reduce current consumption and noise... using stock 2X 0.65A 110CFM Panaflo FBA12G12U, the acq board temp is this...
Personally, I would not risk replacing with fans that have less performance. Because for some reason, LeCroy developers are forced to install these powerful fans. However, your study of temperature changes after installing less productive 0.22A 65KFM fans will be useful for analysis. Do not forget to take into account that the static pressure parameter provided by your fan is no less significant. I suppose that in this situation, when LeCroy oscillograph uses long and narrow channels for air circulation through the ACQ board and a small area of holes in the back wall of the instrument housing (by the way, in SDA6020 the area of these ventilation holes is much larger), this parameter will be very important.
I have ideas on how to reduce the noise from cooling, while not reducing the performance of the fans. But more about that later, after the tests.
A thoughtful analysis of the specifications of different models of fans led me to the conclusion that there is only one way to reduce acoustic noise and at the same time not to lose performance - this is an increase in the useful area of the fan blades. At the same time, in order to maintain the same level of performance, the fan rotational speed can be reduced, which will reduce acoustic noise. But you need to be careful, because the reduction in speed leads to a decrease in static pressure, which also depends on the design of the fan blades (you were probably observant and noticed earlier that small fans emit more noise to achieve the same performance as large fans?).
I have already made initial preparations for this experiment, as well as my way of implementing this principle, you can see in the photo below.
Yes, it will require a small expansion of the opening in the original vibration damping plate for the fans. Alternatively, in order not to do this - you can add 2 more conical adapters 120mm/140mm. Transitions should be as smooth as possible.