The stock fan on the Rigol DS1052 series is fairly loud. In a quiet workshop setting it is more than noticeable.
A modification was described at EEVblog, replacing the stock fan with a much quieter one. So one cloudy day it was done.
The plastic shell of the scope was removed, using 4 screws. The loose plastic part that holds the power connector to the shell turned out to require a little effort to remove.
Two nuts holding the RS232 connector to the metal chassis were removed, the back lid of the chassis was gently popped off.
The original fan was mounted on the chassis. It was a small 12V fan. No wonder it was making such noise.
The fan was removed, and disconnected from the 2-pin main board connector. The replacement fan, perfectly fitting to the chassis, was placed inside and secured to the holes in the chassis with two pieces of steel wire.
A connector adapter between the 2-pin connector on the board and the 3-pin connector on the fan (the fan rotation detector wire was left unused) was made and attached between the board and the fan.
After a brief test, the oscilloscope covers were reassembled.
Scope back, cover removed
Scope back, shielding removed
Small and large fans
Large fan positioning
Fan connector adapter