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DXR15 AMP BOARD OFF

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Re: DXR15 AMP BOARD OFF

Postby Folderol » Sun Jan 12, 2020 10:37 am

It's an input filter choke. The only thing I can think of that would explain that failure, would be a dead short across the following bridge rectifier/capacitor, and/or the main switching transistor - possibly combined with the wrong fuse being fitted.

If it's only the rectifier or capacitor gone it might be recoverable. If it's the transistor as well I wouldn't even bother to look further, and I doubt any other tech would.
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 10:45 am

It is getting repaired and i'm switch to passive and amp system... cant have this happening on a £600 gig
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Re: DXR15 AMP BOARD OFF

Postby Sam Spoons » Sun Jan 12, 2020 12:45 pm

The advantage of powered is that if one speaker dies you still have the other(s) to finish the gig. With a passive rig, unless you carry more than one, if the power amp dies you are dead in the water.

You still have the potential for failure of the mixer but with powered speakers you can plug a dynamic mic and your phone directly into the speaker and still make some noise.
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Re: DXR15 AMP BOARD OFF

Postby Music Wolf » Sun Jan 12, 2020 1:59 pm

Sam is correct. There is absolutely no logic behind the notion of switching to a passive system as a way of increasing reliability (if design, components and construction were of the same standard). In fact you are introducing additional potential failure modes by having to make and break connections between power amp and speakers each time you set up.

Something has gone wrong with the DXR15. It could be a component fault but it could also be misuse or physical damage, in which case you need to identify how that happened in order to prevent a similar thing happening again in future.
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 3:01 pm

Fact remains, the protection system didnt work and the fuse on the board didnt blow instead, wreck the power supply board components making it useless.
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Re: DXR15 AMP BOARD OFF

Postby Sam Spoons » Sun Jan 12, 2020 3:07 pm

True but the same could just as easily have happened to a separate power amp and then you would be left with no noise at all......
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Re: DXR15 AMP BOARD OFF

Postby Hugh Robjohns » Sun Jan 12, 2020 3:20 pm

I totally get the frustration, and potential embarrassment when gear fails on a paying gig.

But the reality of the situation is that electronic equipment will fail at some point. It might be due to handling damage, or water ingress, or a component failure, or old age, or a dozen other reasons mostly outside your control.

Changing to an amp/passive speaker system wont prevent the same thing happening again... Amps can and do fail from time to time, and it will always happen at the most inconvenient moment.

Instead, the more sensible approach would be to build some redundancy into your rig. For example, always carry a spare active speaker(s), a spare mixer, spare cables etc etc, so that there's always a plan B option should something fail on the day.
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 3:26 pm

I get it - more investment - i dont know if the high end systems have all this covered, probably not that that is rocket money i cant afford at this point
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 3:35 pm

anyone know where i can order this part number please>?>
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Re: DXR15 AMP BOARD OFF

Postby Sam Spoons » Sun Jan 12, 2020 3:39 pm

gsc1ugs wrote:I get it - more investment - i dont know if the high end systems have all this covered, probably not that that is rocket money i cant afford at this point

Reliability of cheap gear is sometimes less than better kit but Yamaha is not cheap (more mid range) kit and they have a very good rep (and a 7 year warrantee) so I doubt really high end kit would be much more reliable.

WRT backup gear, see my earlier post.

You'd need to contact Yamaha or an approved service centre for spares. But replacing the PSU board without knowing that there isn't a fault on the main board that caused it to blow is a risk.
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Re: DXR15 AMP BOARD OFF

Postby Folderol » Sun Jan 12, 2020 3:49 pm

A number of points. First of all that drawing does not match what you've actually got.
The double-wound filter choke that you actually have is not shown on the drawing. Nor is the switch.

Secondly, that board is not the PSU it is just the mains filtering and switch (unless there is much more of the board out of view). There is also no sign of a fuse on board, so unless there is one in the IEC plug (and it looks the wrong shape for that) you were relying on the fuse in the 13A plug, and if that was in fact a 13A fuse, then I'm not the least bit surprised at the result.

From the drawing it seems there some sort of relay shunting a resistor. If that part of the drawing is correct, then you have a 0.5ohm resistor intended as a surge suppressor, which is then shorted by a relay contact once the power is up. If that relay fails for some reason then the resistor will get extremely hot very rapidly, which could then account for the rest of the damage.

Failing that I'd say that board was a victim, not a cause.
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 4:59 pm

Thanks for reply, indepth, so the culprit was?
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Re: DXR15 AMP BOARD OFF

Postby James Perrett » Sun Jan 12, 2020 5:12 pm

gsc1ugs wrote:I get it - more investment - i dont know if the high end systems have all this covered, probably not that that is rocket money i cant afford at this point

When I was doing gigs I'd treat the monitor system as my backup. If a problem arose we could make do with one monitor instead of two and use the other monitor for FOH. Commercial PA companies will carry spares for everything - an extra amplifier in the rack and a second power supply for the mixing desk on standby are standard practice.
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 5:18 pm

My monitor is a piece of cr*p but i get what your saying, seems folderol has a point but waiting see why that board failed
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 5:42 pm

This now makes sense, mains filtering board blew because 13amp kettle lead fuse and the fuse im talking about is to protect the main board.
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Re: DXR15 AMP BOARD OFF

Postby Hugh Robjohns » Sun Jan 12, 2020 6:14 pm

No, the filtering board blew because of a major fault somewhere in the rest of the system.

The fuse in the mains plug is not intended to protect the equipment. It is intended only to prevent fires by ensuring the mains power cable is not overloaded. That's why the plug fuse is specified according to the size of power cable.
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Re: DXR15 AMP BOARD OFF

Postby Folderol » Sun Jan 12, 2020 8:14 pm

It really is an odd thing. I've looked over the image a number of times, yet can see absolutely no protection between the socket and the filters. Often there is one in the socket itself, the entire module being a bit deeper than normal and the fuse tray accessible from outside, horizontal below the pins, but that socket doesn't look deep enough for that.
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Sun Jan 12, 2020 9:45 pm

Folderol wrote:It really is an odd thing. I've looked over the image a number of times, yet can see absolutely no protection between the socket and the filters. Often there is one in the socket itself, the entire module being a bit deeper than normal and the fuse tray accessible from outside, horizontal below the pins, but that socket doesn't look deep enough for that.
Your my last hope i think for faith in passive speakers, in your opinion was it the venue or my failed components? I understand now the 6.5 amp fuse on main board did not get a shout in because the choke fried before it. I hope this thread may help others hence the question why a dxr15 blew
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Re: DXR15 AMP BOARD OFF

Postby Folderol » Sun Jan 12, 2020 10:29 pm

No way am I suggesting or even hinting as to which configuration you should use. There are good and bad of both, as well as apporpriate and inappropriate circumstances.

What's more to the point. Where did you get 6.5A from? At mains voltage, that represents 1.5kW :o
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Re: DXR15 AMP BOARD OFF

Postby gsc1ugs » Mon Jan 13, 2020 8:40 am

The 6.5v sorry fuse is on the main board of the dxr15 it did not blow, does that mean i dont have to check the bridge rectifier? Im just checking next the two capacitors next to the blown choke
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