EP2500 Schematics???

[Zero Cool]

Anyone have Behringer EP2500 Schematics???


I have the QSC version but once upon a time i saw someone mention in a thread someplace they had the Behringer version

[serhatkay]

There is Behringer Ep2500 schematic...

http://usera.imagecave.com/serhatkay/Ep2500.jpg

[LAJ]

I've just repaired one of these. It was blown up on both channels. But I think the reason was due to the fan not keeping up with the heat generated. Probably be best to replace the fan (24V) with one that has a higher velocity.

[LAJ]

The early 2500s had IRFZ44s in them for the step up FETs. The later ones had 50N06s. But QSC has a bulletin out on this (style of amp) and says the 50N06s should be replaced with 52N06s. But the package style is different and might not mount up well.

[LAJ]

Be careful with your soldering as these are multilayer boards (5 layers I think). You do not want to pull out a via and lose connectivity to an inner layer circuit.
If your bias pots go open after a failure, 13 ohms seems about right for a fixed resistor to set the proper bias of 80mv across R2 or R106 (Ch1/Ch2).

[Zero Cool]

I just repaired one as well. the 15V zener diode went bad causing the amp to lock up and it took out the triac crowbar output the Fet, all the output transistors, the emitter resistors, base resistors, and just about every other component in that section. But, With the help of the QSC service manual, i was able to get it back up and running pretty easily.

The current fold back test is a bugger however. shorting the output of the amp to check for current foldback then recovery at full power into a 2 ohm load requires a BIG resistor bank!


Zc

[LAJ]

There are four 15V zeners (two for each channel) located on the Ch2 board. My zeners were OK but both 4580s were blown sinking the + & - 15 supplies. Thats because they're DC coupled to the output stage.
I'm surprised Behringer didn't put some glue on those pots. Those bass notes at some high energy concerts are sure to make them "creep".
And the fan needs to be turned around so it pulls cool air in from the front (the filter is on the inside of the front panel). With the fan sucking from the back, it will fill up with dust and you wouldn't know that the back of the filter is clogged.

[strat1953]

the preamp section checks ok.i have signal in and out of ic 4 and 5.voltage looks ood on all transistors? maybe a couping cap is bad? any ideas where to look?
please

[strat1953]

please respond to me directly at strat1953@aol.com

[lorylaci]

Could someone post a pictutre about a PCB from bottom and from top, please?
It would be really helpful.