I have 7 Behringer DEQ 2496 units in continuous usage in 3 different systems. They conveniently allow me to do a wide range of adjustments I need to do, including parametric EQ, graphic EQ, bass limiting, level adjusting, level monitoring, and RTA. And all with midi controllable setting memories. They are useful in multiway as well as (my kind of) multichannel systems.
Around 2013 I discovered I could even use them to replace the Behringer DCX crossovers I was then using. By aligning two "low pass" filters in the parametric section, you can get an LR24 lowpass response, and likewise for the highpass response. This enabled me to use full digital I/O because the DEQ have full digital I/O whereas the DCX only has digital input. Then I can use the DAC's of my choice (so long as DAC latency is corrected for each way and each supported sampling rate...).
I started with one unit in 2005, added the second one in 2008, and on and on. But by 2010 the first one failed, and for me they seem to have lasted 5-10+ years (some of the latest new ones I bought are still going fine, and I've improved the ventilation with higher spacers, and they seem to have improved the parts quality a bit since 2005).
I never fixed any, I just bought new ones like candy as the old ones failed. I saved them in a big pile for "later when I have time to fix them."
I think the time has come to start trying to fix them. They are unavailable new and the used ones (I have sadly learned) may be nearly "used up" if they work at all. I got exactly one year's use out of the last one I bought on ebay for $200.
The latest one (a year after purchase on ebay) has now died with the "flashing screen" problem. When the unit boots up you never get the copyright screen or anything just a flashing screen. Something like half of the ones in my dead pile died with that problem. Others may have the "blank but lit screen" problem, or the "dead as a doornail" problem. I suspect most or all of these problems are power supply related.
Sadly there is no schematic and no service manual. I have found a multipage schematic of some kind but I haven't seen the power supply on it.
I am going to be taking one apart today or soon to see what I can figure out.
Around 2013 I discovered I could even use them to replace the Behringer DCX crossovers I was then using. By aligning two "low pass" filters in the parametric section, you can get an LR24 lowpass response, and likewise for the highpass response. This enabled me to use full digital I/O because the DEQ have full digital I/O whereas the DCX only has digital input. Then I can use the DAC's of my choice (so long as DAC latency is corrected for each way and each supported sampling rate...).
I started with one unit in 2005, added the second one in 2008, and on and on. But by 2010 the first one failed, and for me they seem to have lasted 5-10+ years (some of the latest new ones I bought are still going fine, and I've improved the ventilation with higher spacers, and they seem to have improved the parts quality a bit since 2005).
I never fixed any, I just bought new ones like candy as the old ones failed. I saved them in a big pile for "later when I have time to fix them."
I think the time has come to start trying to fix them. They are unavailable new and the used ones (I have sadly learned) may be nearly "used up" if they work at all. I got exactly one year's use out of the last one I bought on ebay for $200.
The latest one (a year after purchase on ebay) has now died with the "flashing screen" problem. When the unit boots up you never get the copyright screen or anything just a flashing screen. Something like half of the ones in my dead pile died with that problem. Others may have the "blank but lit screen" problem, or the "dead as a doornail" problem. I suspect most or all of these problems are power supply related.
Sadly there is no schematic and no service manual. I have found a multipage schematic of some kind but I haven't seen the power supply on it.
I am going to be taking one apart today or soon to see what I can figure out.
Here is the schematic I found online. https://xdevs.com/doc/Behringer/DCX2496/behringer-dcx2496-schematic.pdf
Start replacing the electrolytic capacitors. Search in the web for "bad caps" or "capacitor plague". 90% of the problems in nowadays electronics are them.
I didn't see the PSU, but if it is of the SMPS kind, it has bad caps inside and is trying to start but can't maintain its self powering logic, thus it recycles continuously flashing the LCD backlight.
If you aren't skilled in high voltage inside a AC/DC converters of the SMPS kind, get help from trained people. There are high voltages and delicate circuitry inside them.
I didn't see the PSU, but if it is of the SMPS kind, it has bad caps inside and is trying to start but can't maintain its self powering logic, thus it recycles continuously flashing the LCD backlight.
If you aren't skilled in high voltage inside a AC/DC converters of the SMPS kind, get help from trained people. There are high voltages and delicate circuitry inside them.
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Starting on which board? FWIW, all of the capacitors (photo forthcoming) look fine except (strangely) a pair in the output section which have some white dust on them. But that might have come from the top cover which has some stuff on it, I'll have to check further.
The only other thing that looked abnormal was a loose melted plastic blob on top of the ferrite clamp which clamps the ribbon cable from the DSP board to the output board. Ahah, I said, the ferrite got so hot (from absorbing DSP generated RF) that it melted some plastic. So I removed the ferrite clamp and wriggled the ribbon connector. No Change. I disconnected ribbon cable to the the output board entirely. Then it goes nuts, all the front panel lights start blinking when you turn it on, but in different ways each time. The display still flashes as before.
I'm still thinking this looks like power supply.
One other thing, the problem didn't just happen. The problem happened when there were some power glitches caused by work on the outside of my house and the power company came and restored power. Sometime after power came back on, I noticed it was haywire.
This particular 2496 was plugged straight into the same wall circuit used for my amplifiers, but differing from the one used by it's AES/EBU source which is on filtered power.
Everything in the power supply looks pristine. Because of the relatively sudden death, I'm thinking diodes or perhaps even filter ceramic caps in the power supply.
I want to check the purity of all the lines from the power supply board. But none are conveniently exposed. It looks like I'll have to study the schematic to see where on the DSP board I can carefully check power with an oscilloscope load.
The only other thing that looked abnormal was a loose melted plastic blob on top of the ferrite clamp which clamps the ribbon cable from the DSP board to the output board. Ahah, I said, the ferrite got so hot (from absorbing DSP generated RF) that it melted some plastic. So I removed the ferrite clamp and wriggled the ribbon connector. No Change. I disconnected ribbon cable to the the output board entirely. Then it goes nuts, all the front panel lights start blinking when you turn it on, but in different ways each time. The display still flashes as before.
I'm still thinking this looks like power supply.
One other thing, the problem didn't just happen. The problem happened when there were some power glitches caused by work on the outside of my house and the power company came and restored power. Sometime after power came back on, I noticed it was haywire.
This particular 2496 was plugged straight into the same wall circuit used for my amplifiers, but differing from the one used by it's AES/EBU source which is on filtered power.
Everything in the power supply looks pristine. Because of the relatively sudden death, I'm thinking diodes or perhaps even filter ceramic caps in the power supply.
I want to check the purity of all the lines from the power supply board. But none are conveniently exposed. It looks like I'll have to study the schematic to see where on the DSP board I can carefully check power with an oscilloscope load.
Actually that blob on the ferrite clamp matched a blob on the top cover. I'm thinking now it was a "tamper" indicator made of some kind of soft plastic to show if cover had been removed.
May be a cazabobos as we say in Spanish. If the set would have a problem in the power line input, surely a MOV or the like would be acted blowing a fuse and rhe entire set would look dead.
The power supply if the SMPS type, probably be inside a metal box for shielding its EMI to sensitive parts.
The power supply if the SMPS type, probably be inside a metal box for shielding its EMI to sensitive parts.
So it can't be a dead MOV then. I think it could be a rectifier or regulator diode of which there are several surrounding a 3cm square. Photos soon
When a similar thing happened to me I changed the big cap in the PSU (47µF, 400+V, 18x25mm). It fixed it and I already had one.
It's the big cap in the lower corner. PSU shown with the cover removed.
it's been running 24/7 since then.
It's the big cap in the lower corner. PSU shown with the cover removed.
it's been running 24/7 since then.
I'm guessing momentary glitch pushed C14 and the big cap over the edge, since they were barely hanging on anyway.
Maybe.
I bought mine like a year ago from a member here. Worked fine for a few days then I woke up to a blank screen and a bit of ticking from the output. I assume he hadn't used it 24/7. At least the repair was quick and easy.
In my case, I use it as an AD/DA do to digital IO with the computer by TOSLink.
I bought mine like a year ago from a member here. Worked fine for a few days then I woke up to a blank screen and a bit of ticking from the output. I assume he hadn't used it 24/7. At least the repair was quick and easy.
In my case, I use it as an AD/DA do to digital IO with the computer by TOSLink.
All my main sources go to 24/96 through digital through miniDSP's for FIR processing, then DEQ's for convenient ad hoc eq and display. Then, FM has it's own processor, and I've added a chairside processor for convenience. It was my chairside processor which went, taking with it my last 5 months of subjective and situational corrections, which somehow I had failed to photograph or record outside of built-in memories.
It looks like the schematic calls for 25V capacitor for C14, but the actual unit appears to be 16V, and it looks like several others are like that. Actual working voltage is 3.3V, but on startup not much separates it from unfiltered power.
I will certainly replace with called for 25v cap. But would even greater reliability be achieved better with 50V cap, if I can fit, or a special type or manufacturer. In one list of manufacturers (Mouser) I see the highest rated reliability for a 25v 10uF capacitor is 5000 hours with the typical standard electrolytic being 1000 hours. Surface mount parts go all the way up to 15000 hours, but thankfully these are radial for easier replacement. So should I get the only listed 5000 hour 25v cap (Kemet) or any old 1000 hour 50V cap?
I would probably get 5000H 25V like this SamYoung NXA https://www.lcsc.com/product-detail...ng-Electronics-NXA-25VB10-M-5-11_C350142.html