I have an Epiphone Les Paul Custom and a Peavey Rage 158 amp. I can't seem to get the distortion to work...Any ideas on how I could?

Switch to the lead channel. Turn down the post gain to 0. Turn up the pre gain to about 8. Then gently turn on the post gain. You should have distortion. Adjust knobs to taste.
adjust your gain switch, or switch channels.
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