Got a Epiphone Les Paul Standard recently, worked fine at first then no sound when I flicked the selector to rhythm. Treble works fine, and it definitely isn't the amp. Can anyone help.
I have an Epiphone Explorer that's had this exact same issue for years....

The wierd thing is its hit or miss, it doesnt always cut out. I'd say 95% of the time my switch will work fine, and then out of the blue you'll go for that neck pickup and it'll be silent.
Ibanez RG1570 - mirage red
Ibanez RG7321
Dean '79 MLF
Epiphone Explorer
Ibanez RX20- first guitar!!
Fender 12 str acoustic
Rickenbacker 620/12
Pod X3 Live
Marshall Valvestate VS-265
+ a bunch more stuff
maybe there is a loose conection to the volume knob for the rythm pick up
I think I might just take it to a guitar shop after New Year and see what they say

My Black Beauty Custom has the same problem...the problem is most likely some dust got into the switch an is causing a bad connection somewhere.

The best way to fix this is to get a can of contact cleaner (from an electronics shop) and spray a little in the switch then flick it back and forth a few times. Then let it dry a little and play away.

Good Luck
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Epi Les Paul Black Beauty
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AB>Crybaby Standard>TU-3>DS-1>DS-2>ML-2>ZW-44>B.O.R.

EHX LPB-1>Phase 90>Milkshake Chorus

"Keep on rockin' in the free world"
Go with LesPAulGuy5544's advice. This is very common with this type of switch and the contact cleaner is cheap.I would remove the back plate behind the switch and use a rag to catch any excess cleaner too.
Moving on.....
Does the neck pup work in the middle position? If so then you know for a fact it's a switch issue.
The cleaner might work or work for a little while. Its well known that the epi stock switches are not very good. Ive seen new ones with bad switches.
Probs Fixed - took it to a guitar shop, turned out it was the pickup, Had to buy a new one. Works perfect now.
Thanks for the help anyway.