Troubleshooting 4x10 cab

Birdland11 · #1 06-21-2011, 08:57 PM

Hey all, i have the acoustic 410 cab,(the one that was on sale at gc for so long)... anyway i was using it with the acoustic head and one night something blew...it was real quiet and farty...so i took the head back and got a new one and it was still messed up...it wasnt the head. I was pissed with it and tired of lugging it around every night,so i bought a markbass 2x10 combo(greatest thing i ever bought by the way) and i have been using it ever since. Now i want to see if i can fix the 4x10 and run it with the markbass, but i dont know where to start. ////I had it apart and none of the speakers are torn or wires fried or anything visibly wrong with the speakers, wires or input plate.I tried it today with the markbass and it was still quiet and farty....What do i look for? what/how do i test speakers or input plate?I used it alot and i kept it in the trunk alot, hot and cold weather...please help ive gotta play some big rooms soon and i need the extra power. Thank you so much

fdeck · #2 06-21-2011, 09:04 PM

Nine volt battery test, for starts. Touch a 9-V battery across the terminals of each driver in succession. You should hear a loud click with each driver. If you can confirm that the drivers are good (whew), then you can follow the wiring back to the jack plate and look for anything that doesn't seem to make sense. You can use your basic mechanical knack and common sense to take a pretty good stab at whether the wiring is OK or not. And if something doesn't make sense, post a pic here.

If you start unhooking things, label the connectors and terminals carefully. "Fortunately I keep my feathers numbered for just such an emergency." -- Foghorn Leghorn.

will33 · #3 06-21-2011, 09:08 PM

Test it by plugging in a speaker cable and touching a 9V battery to it. + to tip and - to sleeve and all 4 cones should move out / - to tip and + to sleeve and they all should move in. Whichever ones don't move are blown.

Birdland11 · #4 06-21-2011, 09:38 PM

Thanks ill try that/// also is there anyway to test the input jack/plate?

Dustin Teel · #5 06-21-2011, 09:42 PM

Could be melted voice coils, especially since you say they got really quiet. A blown speaker can still get relatively loud, but a melted voice coil will greatly reduce volume.

That would actually be a better case scenario, because replacing the voice coil is cheaper than buying all new speakers. If you take out a speaker, disassemble it, remove the magnet, basket casing behind the cone, etc. you will see a piece of metal wound into a spiral. That is the voice coil, and if it is the problem, you will see visible evidence of burns. Like a blackened color as if a lighter had been held to it.

Birdland11 · #6 06-21-2011, 10:10 PM

maybe a stupid question but will one bad speaker make all of them not work?

will33 · #7 06-21-2011, 10:37 PM

In series wiring yes it could. If you didn't get anything testing the whole cab from the end of the cable, take out the speakers and test them indivdually. It's possible to have 1 or 2 bad and not all 4.

Check the solder connections at the jack. If you find a couple speakers that do move with the battery, gently push the cone with your hand and listen for any scraping sounds coming from inside the speaker. If you hear any consider that one bad too.

Birdland11 · #8 06-21-2011, 11:06 PM

im gonna post some pics

Birdland11 · #9 06-22-2011, 04:17 PM

does anyone know how this cab is wired? I took off the connections for the top left speaker to test it, and i forget where they go. white wire from input,white wire from top right speaker, black wire from bottom left. i know black goes on neg but where do the two white ones go????? im an idiot and realized i need to label these////// thank you so much