Hi

I have an old Sony STR-DE525 amp that's not been used for a few years so has gathered a bit of dust and other crud on the top cover and also down inside.

I connected it up to some Tannoy M3 speakers and and played a CD, and although there's plenty of power there is also quite a bit of crackle in the background, but only when changing the volume and only through the right speaker (I changed speakers to check that it was the channel not the speaker). I then connected the freeview box to see what happens and there is continuous low volume background crackle and a low volume overall, but no noticeable static noise when changing volume.

I know the speakers are fine, and the cd player and freeview box cause no trouble when connected to other equipment, so I'm wondering if the dust that has fallen through the grills has settled where it shouldn't be and maybe causing problems between components? It doesn't appear to have the lacquer finish over the circuit board like some other equipment has.

Is there an aerosol cleaner that would be suitable to give the board a good clean? and any other suggestions appreciated. 

Cheers
rev