Where is the usb connection on the Allen Heath GL2400

send a signal thru the sub 4 insert and see if it comes out the sub 4 output. You may have jarred a ribbon cable loose in transport.

Hello,

Carbon track on fader 1 is open because of wear or just broken, if you are getting sound then the ground carbon track is out but certainly the problem lies in the pot.

Make sure your mic cables are XLR to XLR and not cheesy Karaoke type cables with 1/4 inch mon plugs on the end. Please note that I have found some mic cables with wiring errors. They had the shield and one of the signal lines reversed. please verify that your XLR mic cables are wired with:
Go to thiis site and verify your cables:
http://www.toffer.com/wp/2008/08/07/3-pin-xlr-wiring-diagram/
Please note the pin numbers as they may not be what you expect. Ground is actually the shield or braid and the red and black are twisted pair signal lines.

I will ask a question: Did you remember to power ALL inteconnected equipment from the SAME and I do meanALL and SAME receptacle or power conditioner module? If you powered your stuff from several receptacles in a large venue, likely ground system bounce has caused damage. I don't know what you mean by "dont get any signal in."... explain that... There are tests to run to isolate the problem but if you got hit with ground bounce transients you could have major damage. That is a big board for an outside venue so you might describe what you had configured from mics, etc. to speakers. ALL professionals know to run power back from where their amps are to the mixer alongside the snake. I will give you points for carrying a spare... ALWAYS a good plan as electronics DO fail and of course at the worst time.

Cases are being sold on Ebay, new, from several sources, and if you can't find one specifically listed for your unit, contact the sellers as they custom build them. That is a big unit... expect to pay around $150 to $200 for an ATA type case for it.

Here is an example for a Heath/Allen 420. http://cgi.ebay.com/ATA-CASE-ALLEN-HEATH-ZED-420-ZED-420-ZED420-MIXER-/400127078772?pt=LH_DefaultDomain_0&hash=item5d296eb174

I have bought from them before myself and there are others on Ebay so shop around... You can contact the companies and ask for a specific one and DO compare the size to your unit that they specify as all the companies do not accept returns...

Run the RCA cables into TWO channels of the mixer. PAN those two in opposite directions to create stereo signals inti and out of the mixer.

Is this for live sound? You can use your aux outputs as sends if you're not using them for monitors and return to spare channels. If any units are being used for only one channel, either run them in-line (use the effect unit's wet/dry settings) or use the channel's direct out and return to a spare channel.

If one effect is applied to several channels you could put those into a sub group, take that sub output to the unit and return the 100% wet mix to a spare channel.

Be careful not to send the return channels back to any auxiliaries you're using for effects.

Usually the connector that is board mounted is the problem. I would OPEN the unit as there may just be broken solder at the connector inside. If the connector requires replacement, find one at Digikey.com by searching for "power connector coaxial".

Hint: In the future install one of those little lamp switches that are in a little plastic box with knurled knob sticking out the sides. ONLY break ONE wire from the adapter to avoid getting the connections reversed. Since the wires are smaller than lamp cord, tack solder the wires to the piercing points of the switch .

There can be any number of reasons for this problem - solve it diagnostically by starting with something that you know is working and work through systematically to the other end.

1. Test a microphone on a separate amp to make sure it works okay. Check amp and speakers working. Check that all output cables from mixer to amp are working by testing separately.
2. Plug microphone into a channel on mixer. Also plug in headphones and turn headphone volume control up.
3. Make sure input sensitivity knob is turned up a bit (say half way) and main output faders (yellow) are up.
4. Check that channel is turned on (little button just above the channel fader- needs to be pressed down)
5. press pfl (pre-fade listen) button (next to button to switch channel on)- do you get any sound on main output or headphones or any indicator lights on mixer to show signal is getting that far (eitehr the individual channel metering lights or the main ones in the central section)?
6. turn off pfl - make sure channel fader (slider) is up - normal position is ) - about 3/4 of way up. Check lights again on individual channel and main output section - any signs?
7. Is the sub mix button for the channel pressed down - in which case you will need to bring sub mix (red) output faders up as well as main faders.
8. If you have got signs of signal on the individual channel but not main see if the channel has been routed somewhere odd (like a subgroup of channels).
9. Plug a working amp and speakers into one of the auxiliary outputs and use the relevant auxiliary send knob (on each channel just above the faders and pfl switches) to pan some signal to that auxiliary out - do you get anything? There is also a headphone socket for listening to the auxiliary channels (with a selector switch /knob to determine which one - make sure it is in the right position) try listening to the auxiliary output with headphones - anything? If yes the problem lies in the main output section.
10. Check that there is not a jack plug in the insert socket (to route signal through an external effects unit) without a matching return jack being plugged in - if appropriate is relevant effects unit switched on and correctly set up - if unsure remove the insert plug to take it out of the system.
11. Make sure any mute buttons are not switched in on main outputs.

You can download a full user manual here http://www.allen-heath.com/gl/gl2400

Hey tifly415, did you ever fix this problem? My church has the same mixer and last night it did the same thing twice during a congregational meeting. No fan noise, but the meters all peg and we get this horrible descending squeal which gets louder as you pull the faders back in a moment of sheer terror and panic. Power it off and back on and it's ok for a while then it happens again. It's happened to me a few times during rehearsals in the past and it definitely is not mic feedback because no one was near the console or doing anything at the time. It seems to be totally random and unpredictable.

I, too, suspect a power supply problem, but it never seems to happen when my troubleshooting gear is nearby. The only thing unusual yesterday was that the mixer was left on almost all day, so it may have been warmer than usual.

Anyone else have the same problem, or better yet, know of a solution?