Behringer Eurolive B205D

[techie]

I would like to know if someone has a Behringer Eurolive B205D with no output.
This B205D was being used to monitor the output from a bands PA system which was pluged in to the Main IN on the back.
The result was overheating of the trace connection from L2 ( Main In) to pin one on X9 connector.
Now there is no output from any plugins on the front or rear.
Any help about what would cause this would be greatly appreciated.

Thanks

[Enzo]

Hi, welcome.

No Sound Out would be about THE most common complaint about a powered speaker. Unfortunately that isn't very helpful, as there are a bazillion reasons for that to happen. Everything from a open speaker to a burnt up input, and everything in between.

Please tell me no one connected a speaker line to this input. If a signal line is connected to the input and there is mains voltage on the connector, the tiny printed circuit traces will blow like a fuse, as apparently happened to you. In the process other damage could occur, you will just have to sort it out. Is there a power indicator on this model? Does it light up or is there any indication of life? Is the fuse in the IEC connector blown? Inside, are there power supplies present? Etc.

[Chuck H]

This B205D was being used to monitor the output from a bands PA system which was pluged in to the Main IN on the back.
The result was overheating of the trace connection from L2 ( Main In) to pin one on X9 connector.

Does this mean that there was a speaker output plugged into the B205D "main in" input? Because that isn't a mains (as in speaker mains) input.

http://www.behringer.com/assets/B205D_WebBrochure.pdf

[techie]

Thank you for the welcome.

I am trying to find the problem for a friend.
I only know this B205D was being used as a monitor by way of the Main In combo jack on the back.
There was no other equipment plugged in to the front.
It sounds like your right about a possible mains voltage on the connector blowing the traces.
There is a power indicator light on when powered up.
There is faint sound/noise coming from the speaker but there is no volume adjustment or control of the inputs on the front controls.
It seems to be working fine, but there is no amplification, seems like no input is getting to the amp.
All three input channels on the front seem to be dead
The main power fuse did not blow.
I have replaced the blown trace.
Next I will check the main circuit board.

[techie]

Thank you for your reply

[Jazz P Bass]

You need to identify the signal level that was applied to the 'Mains Input' jack.

By design, it's purpose is to connect two (or more) B205D units together.
The Thru is a small signal (like a mic) that is sent to the Mains In of the next unit.

B205D Main In _ Thru.pdf

The above post are asking whether or not an amplified signal (ie: power amp speaker out) was applied to the Mains In.
If so, that is not good.

According to the schematic the Thru signal is derived directly before the Mains Level control on the PCB.

B205D Rear Thru IC3A.pdf

I would set the unit up for testing with a signal going through from the front panel.

Then look for a signal at the output pin of IC7 Pin 8.

It is possible that the only damage , other than burnt traces & L2 being open, is to IC3.

[techie]

Thank You

[techie]

I would like to know where I can find info on Level_3, IC5 which looks like 4500 on the schematic and has
A128A on the IC.

IC5B has input audio signal ( mp3 player ) on pin 6 but no o/p from pin 7.
Also IC5 has 14v on pin 8 and 7.


Thanks

[Enzo]

It is a common 4580. Look at its power connections, lower right on that page, it is clearer.

[techie]

Thank You

[techie]

The Main_IN on the back of the B205D has a connection through L2 to X9 connector.

The Red wire on Connector X9 is connected to IC5 ( 8920 ) on the bottom the Power Supply board through L12, L3, and L1 to the OUT1 Pin 16 of IC5 ( 8920 ) .

What is the purpose of IC5 ( 8920 ) and would a bad IC5 ( 8920 ) cause no signal o/p from the front CD_INPUT, LEVEL_3, IC5B pin 7 ?

Why would an incorrect hookup to Main_IN causing a burnt trace from Main_IN, L2 to connector X9 on the back of the B205D cause no signal o/p from the front CD_INPUT, LEVEL_3, IC5B pin 7 ?

The only damage I can see is on the Main_IN rear circuit board, the burnt trace from Main_IN, L2 to connector X9.

Thank You

[Enzo]

If I shot a hole in you with a gun, there would be an obvious visual clue. If I poisoned you, you would look no different from now. Anything that burns a trace off a board can also damage circuit components, and MOST times they look no different.

The 8920 is your power amp. If it is bad, no input from anything will come out the speaker.

[techie]

There is no audio output from CD_Input, LEVEL_3, IC5 pin 7.

[Enzo]

OK, but you also get no sound from any other input as well, is that correct? Which leads me to ask if you have checked for power supply at the op amp pins.

[techie]

The power indicator light is on.
There is sound coming from the speaker.
There is no sound being amplified from all three inputs.
Everything seems normal except no amplification of the inputs.
Like the amp is in standby mode.