Mackie M800 Owner's Manual - Page 20

APPENDIX A: Service Information WARRANTY SERVICE Details concerning Warranty Service are spelled out in the Warranty section on page 27. If you think your amplifier has a problem, please do everything you can to confirm it before calling for service, including reading through the following Troubleshooting section. Doing so might save you from the deprivation of your Mackie amplifier and the associated suffering. Of all Mackie products returned for service (which is hardly any at all), roughly 50% are coded "CND" - Could Not Duplicate, which usually means the problem lay somewhere else in the system. These may sound obvious to you, but here are some things you can check: TROUBLESHOOTING No power! • Our favorite question: Is it plugged in? Make sure the AC outlet is live (check with a tester or lamp). • Our next favorite question: Is the POWER switch on? If not, try turning it on. • Is the green light next to the power switch illuminated? If not, make sure the AC outlet is live. If so, refer to "No Sound" below. • The AC line fuse inside the cabinet is blown. This is not a user-serviceable part. Refer to "Repair" on the next page to find out how to proceed. No sound! • Are the GAIN controls turned all the way down? Slowly turn them up and see if you hear anything. • Is the signal source turned up? Make sure the signal level from the mixing console (or whatever device immediately precedes the amplifier) is high enough to produce sound in the amplifier. • Make sure the preamp or mixer does not have a Mute on, or a Tape or Processor loop engaged. If you find something like this, make sure the volume/gain is turned down before disengaging the offending switch. • If the speakers are wired for BRIDGE mode, make sure the AMP MODE switch is set to BRIDGE . • Turn the POWER off, check the speaker connections and make sure that there are no strands of wire shorting across the speaker terminals. • Is the HOT LED lit? Make sure there is cool air available at the front of the amplifier. Make sure there is room at the sides of the amplifier for warm air to exit. Allow the amplifier to cool off. • Are there fuses in the speaker or in-line fuses in the speaker wire? Check 'em to see if they're blown. • Make sure the speakers are working properly. One side is way louder than the other! • Do the M•800's meters read the same on both sides? If not, your source signal may be delivering an out-of-balance stereo signal. • Are both GAIN knobs set to the same position? • Are the speaker(s) impedances matched? (See page 22) • Try swapping sides: Turn off the amp, swap the speaker cables at the amp, turn the amp back on. If the same side is still louder, the problem is with your speakers or speaker cabling. If the other side is louder now, the problem is with the mixer, the amp, or the line-level cabling. Poor bass performance • Check the polarity of the speaker cable connections. You may have your positive and negative connections reversed at one end of one speaker cable. This will make the two speakers out-of-phase and cause a bass reduction. • Check that the LOW CUT FILTERs are not turned up higher than the range you want to hear. • Your bass player may need more lessons. 20