20 Most Recent Behringer Bx4500h Ultrabass 450w Bass Amplifier Questions & Answers

Hi,Looks like the power module went out, could be either LM3886T Power IC or Mosfet Module But certainly is in the output stage where your problem is, hope this helps to troubleshoot the issue at least...

Did you check that F1 (red arrows)?. You must open the aluminum cooling in order to find the fuse F1, because it was on the inside, not visible. Usually one of the causes of rupture F1 is one or more diodes (d4/d5/d6/d7) is broken. Check and measure the diode. May also occur, F1 break up just like that, without any other components that causes. This can happen when we open a high level for a long time. It is designed so that the final transistor (which is expensive) not be damaged. Hope it helps.

Contact Behringer to get part number FIRST, then go to this website to see if they have it available. http://www.dbmproaudio.com/behrparts.htmlIt should be a standard 1/4" mono jack, so you can always go somewhere like Radio Shaft or PartsExpress.com and get one. You certainly don't 'HAVE' to get a certified Behringer part for this. Good luck! :)

Contact Behringer to get part number FIRST, then go to this website to see if they have it available. http://www.dbmproaudio.com/behrparts.htmlIt should be a standard 1/4" mono jack, so you can always go somewhere like Radio Shaft or PartsExpress.com and get one. You certainly don't 'HAVE' to get a certified Behringer part for this. Good luck! :)

It is likely the power amp chip has shorted. This puts the unregulated dc into the speaker and you will hear the hum. DO NOT operate this way as you can burn up the speaker. You will find that the LM3886 chip on the heatsink has failed. They are about $7.30 from Digikey. They come in two lead bent versions. Make sure to get the correct version and use heat sink grease wheen installing.

One half of the power amp has failed. You can damage the speaker... do NOT use this until repaired.

I have found that most of the time I can order through allparts.com, however you have to buy the Behringer 'brand' for lack of a better word. Their technology is proprietary, so its difficult to find any other company that sells replacement parts.

First thing is to verify that the power cord is GOOD and that it is fully seated. Beyond that repair is NOT DIY. Take it to a repair shop.

Behinger normally doesn't give schematics... However here is a link to a BX1200 schematic at a foreign site. OFTEN they use the same circuitry within a series of equipment.

http://elektrotanya.com/behringer_bx1200_sch.zip/download.html

Note it is a zipped file of both F and H revisions.

Please note that the symptoms you describe are NOT usually something you will find in the preamp, but rather in the interconnections. It appears that the BX1200 uses TRS inputs at the jacks... not sure what your BX4500 does...

Make sure ALL your interconnected equipment is powered from the SAME receptacle to avoid ground loops and hum. Use balanced lines everywhere possible.

Most Behringer power amps throttle the fan based on temperature sensor(s). The fan will run as needed to prevent over temperature condition.

Chances are you are just needing a new inout connector. They are available by selecting from online sites like Digikey.com and Mouser.com.

If the hum exists with NO input cable plugged in, this requires repair, most likely in a shop familiar with the unit.

The problem may be in the unit's power supply or a broken connection inside.

This problem can also happen if one of the oputput amp transistors shorts driving out DC current into the speaker which is a grave risk to the speaker. Check the DC out of the speaker connector. If it is NOT very near zero, say less than 0.1 volts DC, do NOT copnnect speakers..