Hello i have a epiphone sst studio ,but the jack is un connected,que you send me info about how connect,tanks for the info

Hello Geoff, try using an external processor and check that it works well, if so, the problem is that you have the Jack connectors of Effect sending and those of Return of Effects, dirty
Apply a couple of drops of oil, type WD40, to a Plug connector and insert and remove them repeatedly in each connector Jack for sending and returning effects
I hope you can solve the problem, comment the results
Greetings Franco Dosil

Hola Geoff, prueba usando un procesador externo y comprueba que funcione bien, si es asi, el problema es que tienes los conectores Jack de envio de Efecto y los de Retorno de Efectos, sucios
Aplicale en un conector Plug un par de gotas de aceite, tipo WD40 y entralos y sacalos repetidamente en cada conector Jack de envio y retorno de efectos
Espero puedas solucionar el problema, comenta los resultados
Saludos Franco Dosil
https://media.music-group.com/media/PLM/data/docs/P0A8M/PMP1680S_PMP980S_PMP960M_M_EN.pdf
https://c3.zzounds.com/media/PMP1680S_P0A8M_OI_EN_ES_FR-df44b2314272dfc61a7cabe5bb88ecce.pdf

You should be able to find what you are looking for here http://www.gibson.com/Service/Tech/Schematics/

Or a bad solder connection on the ground wire on the jack, or shell/sheild on the guitar.

Here is the list you seek.
http://www.gibson.com/en-us/Support/TechSupport/Wiring Diagrams/

check out giovanni stores do will be able to help you, it belongs to the chet atkins family guitars

Go to guitarelectronics.com they have wiring diagrams for your guitar there.

Realize that when you plug into the one jack it disconnects the fingerboard pickup from the mix.

DO NOT USE "stereo" cables as it is intended to use TWO MONO cables, one for each side of the stereo.

IF you plug into the one jack that will connect to the bridge pickup, it will disconnect the fingerboard pickup from the mix BUT leave the fingerboard on its own jack.
That same jack will have BOTH fingerboard and bridge pickups IF the second jack (bridge) is not plugged into.

This is according to the schematic. If you find that yours works backwards, then either the schematic is wrong OR your guitar pickups may be electrically swapped.

First, try a different cable. Often in this kind of accident, the connection is broken between the wires in the cable and the plug on the end of the cable. (The cable can often be repaired by soldering the wires back onto the plug.)

If that doesn't help, it's possible the input jack on your amp was damaged. It is a relatively simple job for an amp technician to repair or replace an input jack if this is the problem. Expect about 1 hour of labor and about $10 in parts.

If this is a classic guitar you should take the fretboard problem to a luthier as you could de-value the unit by working on it yourself.

The jack you can replace yourself. Just connect the wires to the new one the way they came off the old one. There are ONLY two wires. You can get replacement jack from severaal sources.

This will help for starters:http://www.epiphone.com/images/EpiOwnrsManul.pdf This site has good info in the discussion:http://www.thefret.net/showthread.php?t=4728 There's info here too:http://epi.p3net.net/bbs/index.php.

There should be two wires connected. One goes to the jack tip while the other goes to ground. One lug on the jack is connected to the part touching the sleeve on your cable while the other will contact you cable's tip. There is another wire in there somewhere.