I see there is a separate topic related to that unbelievable noisy fan in the Rigol's scopes, but why not to replace a fan, when the scope is opened for JTAG dump ?
I have done it today. Let me share some noise level measurements done with a smartphone :
1. Scope is off, quiet room : 20 dB
2. Scope is on, smartphone located 10 cm in front of the scope : 50 db !
And now, when the new Noiseblocker 60 x 60 x 25 mm fan, model XR2 is installed (costs 6.50 euro) :
1. Scope is off, quiet room : 20 dB
2. Scope is on, smartphone located 10 cm in front of the scope : 30 db, very nice, incomparable to the original fan.
Conclusion : highly recommended replacement, no risk of warranty loss, as the fan is plugged into a connector. If somebody is interested, photos can be attached.