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Post by thompson12 on Oct 30, 2022 16:12:06 GMT -5
Thanks for the links Mitch
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Post by thompson12 on Oct 30, 2022 19:26:22 GMT -5
Frankly I would keep it the same. Also since you are in there I would consider recapping your XPA-5, it is getting up there in age. Especially vulnerable are the controller. That can't ever die as getting replacement is neigh impossible. True also on the XPRs too. Which caps would you recommend replacing? Mitch
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Post by vcautokid on Oct 30, 2022 21:06:20 GMT -5
If possible all of them. But especially the ones close to the microprocessor controller. Power supply caps and anything near the pre drive.
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Post by 405x5 on Oct 31, 2022 9:56:57 GMT -5
The questions under score of the point that no one but qualified personnel should be under the hood. The parts changer will ask questions and change parts. A professional will test and determine why something happened and with the bench testing determine what needs to be done. that being said, the persistence is admirable.
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Post by markc on Oct 31, 2022 10:26:06 GMT -5
If you like the Gen 1 amps, I’ve got an XPA-2 & XPA-3 I’m going to be listing…..they both equal an XPA-5 😳🤣 I would suggest you consider buying an XPA-2 and pulling one of the amps from there to replace your blown one. You COULD replace all the visibly damaged components, but it could just be flogging a dead horse.....
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Post by 405x5 on Oct 31, 2022 11:31:04 GMT -5
…… time to go shopping
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Post by donh50 on Nov 1, 2022 13:52:53 GMT -5
Random thoughts:
Looks like outputs, drivers, and perhaps some biasing components may be fried. I'd ask Emotiva for a service manual or at least full schematic to look for other problems before swapping (and likely destroying) new parts.
I don't see evidence of bad capacitors in the pictures after a quick look but hard to see; better "being there".
Discontinued parts make repairs these days a huge hassle. Replacements can be hard to find and require careful reviews of specs for compatibility.
Emotiva's record for repairing older components has been hit and miss from what I have read here and elsewhere. I would certainly start with calling and/or emailing them for help and perhaps repair if they can/will do it. Probably cheaper and much less aggravating in the long run, especially if your time is considered.
I don't really miss my repair tech days... - Don
(Although blown amps are "easy"; the hard repairs are when distortion is 0.01% instead of 0.001%...)
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Post by leonski on Nov 10, 2022 15:27:32 GMT -5
Sketch-O-Matic is a MUST.
Good call, don......
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Post by audiosyndrome on Nov 10, 2022 16:53:47 GMT -5
You’ll be chasing your tail trying to fix that amp section. EMO would just replace the assembly. Much cheaper than spending the time to TS. Pull out the bad amp module and make it into an XPA-4 (hopefully). 😅
Russ
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Post by leonski on Nov 10, 2022 18:13:00 GMT -5
Audio, you are making LOTS of sense....but for some associated reasons.
first? when you get smoke / heat like that out of an amp you have CHARRED the circuit boards. they will NOW CONDUCT and unless you get in there with a DREMEL and treat the char like Tooth Decay, you'll NEVER get it right. And given that the boards probably don't have VERY heavy plating, you are going to be 'replacing' traces as well.
This will turn into a Science Fair project..... I really HATE disposible / non-fixable stuff. Cars included.....
This is unless you got REAL LUCKY and all you have is some charred semiconductors and maybe a few resistors......But given the description, I'd guess.....Not Likely....
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KeithL
Administrator
Posts: 9,961
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Post by KeithL on Nov 11, 2022 18:01:33 GMT -5
The real catch is that you rarely lose just one or two parts... with any direct coupled amp, when an output component fails, there is generally a cascade that takes out several other parts. (This is true for any direct coupled amp... not just ours.) The Catch-22 is that, if you replace some but not all of the failed parts, your new parts will likely get fried when you try to power it back on. My XPA-5 GEN 1 shot down on its own and when I turned it back on smoke poured out the top. Every time I turned it back on channel 5 flashed red and shut down. After pulling it out of the setup and opening it up I found the culprit. View AttachmentView AttachmentView AttachmentPart #A1837 on a good one. Anyone have suggestions on up grades or keep it the same? View AttachmentMitch
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Post by leonski on Nov 13, 2022 17:22:40 GMT -5
Keith's post is among the reasons that some tech's won't touch this kind of thing.
Fix it? 2 weeks later it's BACK and the customer is angry. It can turn into a no-win situation
where the tech is frustrated and wished he hadn't touched it and the amp owner is torqued since
the STEREO IS BROKEN and he ain't getting his music fix.....
That's why bench work and 'module' changing is popular. change the module and get the amp
back to its owner.....than fix the module......But you charge accordingly and need a decent turnover
of THAT product / line or it doesn't make any money sense at all....
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Post by audiobill on Nov 13, 2022 17:29:28 GMT -5
KeithL was mystified why McIntosh uses transformer coupling in many of their output stages. Well, he has just described one good reason, their amps can take a direct short across the output terminals, protecting your investment from this sort of calamity.
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Post by leonski on Nov 13, 2022 18:09:47 GMT -5
Transformers or Autoformers? I hate to be 'picky', but I think SS Mc uses Autoformers? Might be part of the Mc 'house sound'.....
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Post by audiobill on Nov 13, 2022 18:25:57 GMT -5
Yes, autoformers, but the point is the output transistors are protected from catastrophic failure. And if accurate musicality is a "house sound" so be it!
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Post by leonski on Nov 13, 2022 19:38:15 GMT -5
NO QUESTION you like your Mc! The Grateful Dead would be Jealous.....
I've never had 'multiple' systems or more than Briefly (like weeks, tops) 1 pair of speakers...
Except for my Garage System which is partially FOUND and of near-zero value and that Uber Expensive amp.....the 35$ Parts Express DT-1
That amp? Really special and I'd LOVE to try it with some Very high sensitiity speakers. I has room internally for 8x AA Batteries which should be
quite the quiet PS....
I have a PAIR of ancient Minumus 7 speakers which still work but I have no place to put 'em....
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Post by 405x5 on Nov 14, 2022 10:27:05 GMT -5
I had an AR integrated amplifier that actually did this….fire coming out of the top! The whole smash 💥! Can such a thing be fixed? Answer yes. Professionally repaired by Forbes Electronics as it was under warranty and they were pissed at me, although they honored the warranty. Still a teen when that happened. I looked through the top with a flashlight 🔦 and could see some black aftermath from the fire, but it worked fine for the duration.
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KeithL
Administrator
Posts: 9,961
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Post by KeithL on Nov 14, 2022 10:57:45 GMT -5
Uhhhh... that's not correct... or not necessarily correct. The autoformers DO NOT protect the output transistors from a short circuit or zero-load. (Their amplifiers may indeed be able to tolerate a direct short across the output but that is not why.) What the autoformers do is to protect your speakers from certain types of catastrophic failure of the output transistors. A full transformer simply will not pass DC... so, if the output devices were to fail in such a way as to apply DC to the load, that DC would not pass through the transformer. This will in no way protect the output devices... what it will do is to contain the damage to the inside of the amplifier. An autoformer does not actually provide DC isolation between it's input and output... However, if the output devices were to fail, the autoformer would "crowbar" the resulting current, again mostly preventing it from being applied to your speakers. (This was a significant benefit back when output devices were prone to failure and most amplifiers lacked other types of protection circuitry.) The main benefit of autoformers is that they enable the output stage to see a relatively consistent impedance with different loads. This enabled the amplifier to deliver the same amount of power into different speaker impedances. (So you avoid having to optimize the amplifier to deliver maximum power into a specific impedance... which was a big deal when amplifier output power was at a premium.) The downside, of course, is that transformers are big, heavy, expensive, and impose all sorts of other issues and limitations. (To be fair McIntosh has always had great transformers... which minimize the performance downside... but not the size or cost.) KeithL was mystified why McIntosh uses transformer coupling in many of their output stages. Well, he has just described one good reason, their amps can take a direct short across the output terminals, protecting your investment from this sort of calamity.
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