As so many I finally decided to change the fan in my DS1054Z for a quieter one. The Gelid Solutions Silent 5 (FN-SX05-40) has very similar data to the originally installed Sunon ME50151V3-000C-A99. It is hard to judge if the airflow is indeed the same, even in the throttled mode which is used by the scope. Because some of the chips run hot to the touch, I took the chance and upgraded the heatsinks as well.
Here is the heatsink for the main aquisition FPGA: 70mm x 25mm fit very nicely. The cuts are on an angle on purpose to avoid tall components on the board.
On the ADC and main application processor I used stick on heatsinks from an old graphics card heatsink kit.
With these modifications the scope runs much quiter and cooler. I’ve had no issues since the upgrade.