[drh4683]

Its ok to use a higher capacitance (such as 100uf in place of 80uf). Try to keep voltages the same. Obviously dont use a 250volt cap in a 450 volt place.
Its not advisable to use a higher voltage cap in a lower voltage circuit (such as 450 volt cap in place of a 250) Reason being, when a capacitor is not used to its full potential, it has the tendancy to dry out sooner. Best way to describe it, the capacitor is not being saturated with enough voltage.

Some caps in the cans are rated at 475 volts, its ok to use a 450 volt in its place. Voltage doesnt reach that high. The 24MC32 (your chassis) only has B+ voltage of 350 at the highest. (B+boost is different and generally lot higher voltage around 800volts. That doesnt apply here but just wanted to let you know)

If I remember correct, your TV is a 24MC32?????

In that case, these are the filter caps:

these two caps should not be grounded directly to the chassis:
160uf@250v
160uf@250v

These next two caps are grounded to the chassis
80uf@475v
100uf@475v

Im reading numbers directly off a factory zenith schematic. Look at the power supply section of the schematic and you will notice the B+ voltage can be read directly off the terminals of the filter caps.

Measure voltage on the lug of the 100uf@475 with the set on, reading should be 250v
Measure voltage on the lug of the 80uf@475v with set on, reading should be 350v

Small voltage variation is no problem. Check voltages in DC mode and see what you come up with first. This way we can pin point where the trouble is. This is the best we can do w/o an oscilloscope handy.