Vintage Synth Repair

--- In vintagesynthrepair@y..., Peter M Blackett <dragonser@c...> 
wrote:
> HI,
> in a lot of older power supply units its likely that the 
electrolytic
> smoothing caps may need changing .
> this applies to both the linear and the switched mode supply units .
> modern electrolytics may be smaller that the older ones you are
> replacing .

Hello Peter,

Can this account for the hum coming from the supply?  I mean the 
supply itself actually hums and crackles.  I don't mean not hum and 
crackle in the audio path.  The supply actually sounds like 
electricity sound efx from 1930s/40s b-grade sci-fi and horror 
movies. 

Thanks again,

Ethan