When I plug the guitar into an mixing board/amp no sound comes out. From the mixing board, I can see that the mixer is receiving a signal but still nothing comes through the speakers. I own a Fender CD140SCE

the easiest way to mix less effect sound and more natural guitar sound is to reduce the level of the individual effects within the patch selected. The more challenging method would be to go through a splitter box 1st, or any stereo effects box, to split the signal, and then you will have 2 outputs, one dry, one through the Zoom. The 3rd (and simplest ) method would be to place the Zoom in the effects loop of an amp that features a send / return balance adjustment.

This is not a powered mixer and so you must connect a power amp to the "line level" outputs of the mixer. Other "no output" problems could be related to buss assignments and other signal routing issues. Check for output by connecting "Main Out" left or right to a guitar amp input instead BUT turn all volumes down to zero before conductiong this test as guitar amps are designed for "Microphone" level inputs. Owners and Hookup manuals can be found here...

http://www.mackie.com/products/1604vlz3/

There are a number of configurations for a mixer like the 1832, the most common are PA system and Recording system. There are Main output jacks which carry the mix as summed in the main faders. These in a PA system would feed the pa amplifiers which drive the house speaker system for the audience. These connectors are XLR 3 pin type on the rear, intended for professional pa amplifiers which use balanced +4dbv line input level. Amplifier which have 3 pin XLR connectors for input signals can accept that high level signal. For home style HiFi amplifiers, the signal level is nominally -10DBv and balanced or unbalanced signal lines with 1/4in diameter phone plugs which are connected to the mixer by way of a second set of Main output connectors which are 1/4in phone jacks. Use whichever amplifier input level your amp has.
If you are not using it as a main PA house mixer, but using it for recording, the main output connectors go to a 2 channel recorder or computer sound card recorder. The power amp and your monitor speakers are connected to the connectors labeled "Control Room" (CTRL Rm). These output are useful for recording because the signal through the mixer can be monitored from several buses, Solo, main mix, selected by buttons provided. The buttons only affect the signal heard through the control room monitors, and not the main output which only sees the main mix so selecting "solo" does not interrupt the signal going to the recorder while the engineer in the control can be checking other signal paths through the board.

you can use the record outputs to run the signal into a stereo receiver without problems, though it would likely sound better with a shure sm57 microphone hooked up to a mixing board or other instrument amp.

the record output should be PERFECTLY balanced to hook up to a consumer-level stereo reciever with NO distortion; however, this record output might be too loud for another instrument amplifier or a mixing board; hence, the microphone in the latter situation.

short answer- "yes, but..."

This is probably not a DIY repair. You best take it to a repair shop. Likely the power amp has failed or other common problems are broken connectors/jacks, broken volume pots, and finally circuit board cracks.

I suspect one of the upfront IC amps has been damaged. This can happen if people power the mixer from a receptacle that is different from where other connected equipment is powered such as amp. For example, mixer is at one end of the hall and other inouts such as an output of a guitar amp is plugged in. If a ground fault or spike occurs, teh ground bounce can exceed the common mode voltage of the input amps.

In your case, the inpout amps are discrete transistor types.

A voltage surge into the inputs of your unit would LIKELY pop two bypass caps that are 330pf. For channel 2 these are C205 and C206. Check those for shorts.

VERIFY audio is available at the "send" (tip) of the channel insert connector... this verifies the preamp stage. You can PROBABLY plug a set of headphones in to check this... ONLY one side will have sound of course. Verify this is a good test by checking a working channel. The level will be quite low and we are looking for just some signal.

IF you do have signal on the channel insert send which is the "tip" of the channel insert with the trim turned up, let me know and I will check the schematic for the next thing to check farther down the line.

You will need at least a 24 channel mixer to give you spare channels. You also need an active crossover and a snake. The advice you need is too much to include here so I am including some links:http://mixonline.com/live/FixIts/, http://en.wikipedia.org/wiki/Live_sound_mixing, http://mixinglivesound.com/blog/tag/outdoor-concerts/,http://mixinglivesound.com/blog/, and http://www.scribd.com/doc/11435651/Beginners-Guide-to-Mixing-Sound. You may need more monitors than you are planning on and you might consider in ear monitoring.

Quick and dirty way is to turn up one of the AUX channels, say #1 on the Guitar player's inoput channel/strip. Have all other AUX #1 completely CCW so none of the others get mixed on the AUX.

Use a TRS cable from AUX1 output to the guitar players monitor amp.

NOTE. The signal to his amp will only be controlled by the AUX1 on his channel AND the AUX1 Master.

One normally uses the AUX outputs for monitor functions.

You don't specify which model Phonic mixer in question.
Is it a powered mixer ? And are you plugging your speakers into the speaker outputs ? If it's not a powered mixer and you're plugging speakers into the Line Outputs, you're not using a power amplifier between the line outputs and your speakers - this won't work.
If it is a powered mixer and you are plugging speakers into the speaker output connectors and still getting little or no sound, check your speaker cables and the speakers themselves by plugging them into known good amps.