measuring that voltage wont tell you a lot of information. You need to see signals in an audio circuit and those transistors could be MOSFET and or they cannot be tested while in circuit.
Much depends on the noise and where it is originating. The deck doesn't seem well thought of and it is unlikely the manufacturer has a spare parts service - unless you have the skills needed to locate and rectify the "noise", which could be electrical, electronic or mechanical, and otherwise restore the deck it would seem advisable to replace it.
