In early Spectra radios, notably those that are 12-15 years old AND that still have their original RF and command boards, there was a tendency for several capacitors on said boards to leak and dry out, often contaminating the boards themselves in the process.
The most notable symptoms of this problem are audio distortion and/or audible noise (a 'rice krispies' effect has been described by some), or perhaps loss of audio altogether.
You can also see physical evidence of the problem by inspecting the solder pads for the capacitors listed below. If one or both pads have a dull gray appearance, as opposed to their normal silvery shine, or if a portion of the board's solder mask is visibly discolored near the suspect parts, you've got leaking caps.
The fix, in summary, is a 'shotgun' approach that has proven to be very successful, at least with the Spectras that the WA State Patrol is using as area receivers in their cruisers. I've rebuilt three units (so far) with this fix, and all have made a full recovery.
There are a total of 11 capacitors and one IC that need to be replaced, as follows.
U450, Audio PA chip: 51-80065C19, 1 Ea.
C451 & 452, 23-11049A37, 2 Ea.
C459, 460, 461, 605, 608, 632 & 635, 23-80090M06, 7 Ea.
C636, 23-80090M07, 1 Ea.
C456, 23-80090M24, 1 Ea.
Note that the 400-series parts are on the command board, and the 600's are on the RF board. They're all surface-mount, with the exception of U450, but I've not had any trouble replacing them with a little patience and the right touch. A magnifying lamp helps as well.
Total parts cost should come to less than $30. Good luck!
