Behringer Inuke NU1000 not powering on.

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Hi everyone,

This is my first post, I hope someone out there can help me.

I have a Behringer iNuke NU1000 class D power amp that's not powering up. I have spent a good amount of time on it now and cannot find the fault. :confused: I can't find a schematic diagram for it anywhere on line. I contacted Behringer they give me no information at all.


When powered on I have 240V AC up to the Bridge Rectifier, 330V DC out of Bridge Rect into smoothing caps.
Voltage at smoothing caps, 329V & 163V. The caps are in series 1500uF @ 200V each, both testing good on Peak atlas ESR tester.

large TX is getting 163V.
Power Transistor on right in picture is receiving 330V on the drain (centre pin 2) with no voltage on gate & source. Source of this trans is connected to Drain of left power Trans.
Power Transistor on left in picture has 0V on all pins.

VIPer22A Current mode PWM controller is getting
7V on VDD (switched off). According to data sheet it needs to be typically 14.5V at which the device starts switching.

KA3525A Pulse width modulating regulator has no voltage at any of the 16 pins.

I replaced VIPer22A primary switcher, KA3525a pulse width modulating regulator and both power transistors 6R199P and still no joy. I tested all components on the primary & secondary side of the board mainly looking for shorts and all seem to test good.


The unit is about 2 years old and was installed in a primary school where it was probably power cycled for use with volume level full on and switch in on position.


If anyone can give me any advice at all, I will be delighted.

Thanks
Paul
 

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Hi workhorse,

Thanks for reply. From my research the white coloured relay is not fitted on the Inuke NU1000. The pictures where taken before any troubleshooting began. I bought the amp new so I know nobody else has worked on it.

I attach a picture of a Behringer Inuke NU3000. It has the Relay you describe in place. If this relay was faulty then no voltage would be present on caps.

Regards,
Paul
 

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I'm gonna hazard a guess, and say that the trouble may well be in the stand-by section of the power circuit.

If the ViPer22 isn't powered/working, nothing is. I'd point my attention to the so-called "start-up cap", which is filtering the Vcc rail of the ViPer22. That should be (replaced with) a low-ESR cap from a reputed (Japanese) brand, of similar value and voltage rating.

After that (or if that doesn't revive the thing), i'd direct my investigation towards the secondary of the stand-by section, particularly the caps on the rail from which feedback is taken. In ATX power supplies, dying / dead caps on the secondary can (and do) screw up the feedback signal, which makes the associated primary section go a bit haywire.

PS: I've got a hunch that relay on the NU3000 is there just to bypass the thermistor, after a certain delay. So with or without the relay, you'd still have voltage across the primary caps :)
 
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Hi everyone,

I have changed all 17 electrolytic caps around VIPer with exact same value Panasonic low ESR type. I used surface mount instead of SMD just because I don't like SMD caps. I have checked all SMD resistors in the board and I am getting sensible readings. All diodes check good too. I am still not getting any power up :(

I notice pins 2 & 3 on VIPer ( source & feedback are connected with a small SMD cap. I tried to measure the capacitance of this but was unsuccessful. I measure 1.7K across it both ways with no charging effect. I would like to change this component but have no values.
Pins 5 to 8 on VIPer each have 220V dc.. VDD is still around 7v dc..



Paul
 
SMD = Surface Mounted Device; did you mean you replaced the original surface-mounted caps with through-hole (ie. legged) ones? :)

http://www.st.com/web/en/resource/technical/document/datasheet/CD00087939.pdf

The link above is the datasheet to the ViPer 22A. On page 11 there's some details about the start-up sequence. The second paragraph on that page caught my eye:

"Note that during the real starting phase tss, the device consumes some energy from the VDD capacitor, waiting for the auxiliary winding to provide a continuous supply. If the value of this capacitor is too low, the start up phase is terminated before receiving any energy from the auxiliary winding and the converter never starts up."

Also, see the schematic at page 7? See if you can find which components on the power supply board correspond to R1, C2 and D1 (which comprise the RCD snubber / clamp, across the transformer's primary). I've seen a couple of such flyback psu's "killed" by sub-specced snubber components.

PS: You're measuring 220v *DC* from pins 5-8, relative to what? As in, your black (negative) multimeter probe is connected to... what? Ireland has a 230V AC network, doesn't it? That should translate to something in the region of 315-325V DC after rectification. Perhaps it might be worth checking the rectifier bridge as well?
 
D23 = ER1J = 1A 600v superfast rectifier - assuming your multimeter has a diode test function, what are the readings, both ways?
D21 = 1N4148 in MiniMELF package -> is it just the camera angle + lighting, or is some of the glass casing chipped off? You might've nicked that when replacing the cap next to it - for reliability's sake, you'll wanna replace that.
R147-150 -> "from end to end", does the measurement read something in the neighbourhood of 50Kohms?

It might also be worth (double-)checking, or replacing, the optocoupler (by the markings, seems to be a PC817 equivalent). These rarely fail, but it's not unseen before - if memory serves, a friend of mine encountered failed optos a couple times, and the PSU came right back to life after replacing it.
 
D23 = ER1J = 1A 600v superfast rectifier - assuming your multimeter has a diode test function, what are the readings, both ways?

Measuring across D23 = 0v and 0.499v
D21 = 1N4148 in MiniMELF package -> is it just the camera angle + lighting, or is some of the glass casing chipped off? You might've nicked that when replacing the cap next to it - for reliability's sake, you'll wanna replace that.

Yes it does seem to be chipped alright. From my lack of experience how do you know what size D21 is? It has no markings on it at all.

R147-150 -> "from end to end", does the measurement read something in the neighbourhood of 50Kohms?

Yes 49.85K ohms. on both lines R147 - 150 and R148 - 149.

It might also be worth (double-)checking, or replacing, the optocoupler (by the markings, seems to be a PC817 equivalent). These rarely fail, but it's not unseen before - if memory serves, a friend of mine encountered failed optos a couple times, and the PSU came right back to life after replacing it.

Will order in optocoupler and replace. There is two EL817 optocouplers.. I'll change both of them with pc817's. In the attached picture I've removed some components for clarity
 

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Yeah, that looks like the proper part :)

I'm pretty sure (only) IC5 is connected to the ViPer chip - i've yet to see more than just a voltage feedback opto, for one of these low-power stand-by flybacks.

PS: Now that i get a better look, even though those are indeed Panasonic caps, i'm afraid they're very much NOT from a low-ESR series. 85c temperature rating => general purpose series; blue sleeve = M series? (i believe the SU series is discontinued).

All low-ESR series have 105c ratings, and some examples from Panasonic are the FC/FM/FK/FR series.

Oh, and C27, by how the traces are going, may well be the "last" filter cap before the ViPer's VDD pin.
 
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Sorry for not getting back sooner. It's extremely busy around here and I'm only getting a chance now to update.

As khron pointed out above I did have general purpose caps in as replacements. I did get around to changing these all to Panasonic low ESR 105c ratings.. I changed D23 and D21 ( mini melf). I changed the two optocouplers.. I tested the thing again and still had a dead amp. So I left it for a while to work on a crown 2400 macrotec power amp..

With the crown macrotec repaired and returned to the customer, again I stand here looking at this dreaded piece of behringer equipment.. I guess I will have to do a bit more research into it.

Will be posting if I get a result.

Thanks to all for giving me advice.
 
No Problem!

My amp died suddenly too, I guess it is the same reason as yours.
It worked ok night before. the next day I powered it on and thought I heard an electrical spark-like sound coming out of the wall plug. Could have been the internal fuse that failed, but if it really came from the wall socket, it could be equivalent to cycling the amp on & off while powered on (bad connection between cord legs & wall socket?).

Anyway, mine isn't covered under warranty anymore and it is an early production model since it was bought june 2012 and those seem to have a bug, even confirmed by Behringer (Behringer iNUKE NU6000 amplifier - Page 4).
I am however in South America and sending the amp back would not be cost effective.

Ive brought it in for service to a non authorized repair shop (no Behringer authorized shops in my country), and the first parts found faulty were the two 6R199P transistors. I cant find them locally, and have ordered them online. The repairshop also referred to them as HAP-104 & HAP-108, but could find any info on that code.

I will keep you updated on this, but since you also replaced the 6R199P and didnt get it working, my hopes arent set high..........
BTW, do you have the full part number of these 6R199P transistors? mine are blown apart and I barely could make out the code stamped on it.....wondering if I ordered the right ones as all I see on the net are 3 legged ones and the originals are 2 legged....

Looking forward to your responses!!!
Thx (& sorry for the hijack!)
 
A quick google search brought up the part as actually being an Infineon IPI60R199CP.

http://www.infineon.com/dgdl/_rev2....90004&fileId=db3a304412b407950112b42c77ea4707

Sounds like these are the main switchers in the main power supply. And yes, if they're shorted, then "even" the stand-by power supply won't have much voltage to work with, if any. Odd, though, that the fuse is still intact(?)

I recall a small adage that a friend of mine likes to use (taken, i believe, from Dave @ EEVBlog) - "Thou shalt measure voltages" :D
 
Looked up the link you posted. Are you sure its a 3 prong part? Went back to the shop and asked if it was a 3 prong part.... Sure enough it seems its 2 prong in the nu1000. Have pics in mu phone that show 2 prongs...not hosted yet, but will post them once ive uploaded them...
 
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