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It's not uncommon if a set was in a living room close to a kitchen or if there is a coil or transformer containing wax close to a part for it to get an oily or waxy look. One check you could make if you don't have a leakage tester is to put a cap of over 10X the value in series with the low voltage end of the ceramic caps ( a .1uF will work for anything smaller than a .01uF) then measure the DC voltage of the point between the two caps. The voltage may initially float up but it should 0 out within around 10 seconds of connecting the DMM...If DC voltage doesn't 0 out within a reasonable amount of time you have leakage.
Putting a large test capacitance in series with a small test capacitance will yield an effective series capacitance close to that of the smaller capacitance, and the greater the difference between the two the closer the effective value comes to being unchanged from the existing small value.
AGC does need manual bias voltage injection if the automatic part is disabled....Heck if the automatic part is not disabled, but isn't working right using a manual bias supply to force it to the value it needs to be can be used as a troubleshooting procedure...The exact voltage it needs to work may be different than the one listed in the alignment procedure as the signal level may be different and the alignment procedure may desire adjusting amps at min or max AGC gain for linearity reasons.
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