Carver M1.5t Repair Testimonial - Circuits and Concepts

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indyaudio
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Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by indyaudio » Sat Feb 22, 2014 12:14 pm

I bought a 1.5t couple years ago, had the telltale 60hz hum, so knew it was going to need repair at some point in time. It was a constant low hum, so for my office system was fine, with any music on even at low volume you couldn't hear it. I got by with this for 2 years, then in December, turned it on and LOUD.

Determined the 50/80 v capacitors in the power supply were the culprit and bought a replacement kit from Circuits and Concepts on Ebay.

The kit was very reasonably priced and built to be plug in as the original parts are no longer available. Great quality.

I attempted to remove the old ones, but my desoldering skills were not up to the task, so Circuits and Concepts got my amp and within a week, back and good as new.

I cannot recommend them enough. The area where these sit on the circuit board is tight and the number of points needing to be clean for removal is pretty tricky. Give it a try, but know he's there for you as a fallback, including shipping, all at a very reasonable price.

Good as new and should be trouble free for many years to come.
Main Room System(s):
Speakers - Polk SRS 1.2TL; Carver ALiii; KEF 101, 104/2; Pioneer HPM150; JBL S7R Sovereign, L112, 4312, 43111
McIntosh - C28, C26, C24 preamps; MC30 monoblocks, MC2205, MC2120 amps
Carver - M4.0t amp; CT17 preamp; C9 Holography; Digital Time Lens; SDA360 CD
Sunfire 300~2 (2) & Dynaco ST-70 tube (2) amps
Jolida tube & Linn Karik CD; Rega P2 & Marantz 6300 Turntables
Arcam rDAC

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TNRabbit
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Re: Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by TNRabbit » Sat Feb 22, 2014 12:55 pm

Thanks for the info!
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trav0810
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Re: Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by trav0810 » Sat Feb 22, 2014 1:28 pm

Always good to hear about a great service experience. Thanks for sharing!

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fill35U
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Re: Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by fill35U » Sat Feb 22, 2014 4:27 pm

Thank you for the source! Glad Les took care of you, he makes some very useful parts!
Living room system: TGP IV, TX-8r, TD-1400, PT-2400(x6), PM-1.5a(x3), TFM-45(x2), TFM-55, Silver Amazings Mk IV

Spares/projects: C-9, M-400, PM-350(x2), M-1.5t(x2), PT-2400(x2-1/2), PT-1800(x4), TGP I, Architectural True Sub, pm420

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Robert R
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Re: Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by Robert R » Sat Feb 22, 2014 5:01 pm

Good as new and should be trouble free for many years to come.
Well, it's NOT new, and how many years (or weeks) before any of the dozens of other electrolytics fail is anybody's guess. But fail they will, for sure; they are the same age as the ones that already went. If you want trouble-free years you need to give it a complete recapping, imo.

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bob p
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Re: Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by bob p » Sat Feb 22, 2014 6:09 pm

I'm glad to hear that you've got your amp up and running, and I'm sorry to hear that you had problems along the way that forced you to reach out to a repair facility. The type of cap job that you're talking about isn't at all hard. It's something that anyone with decent soldering skills should be able to do on his own if they have all the right information.

Once upon a time I had written a complete tutorial about re-capping the low/mid rail caps on the 1.5 type amps, so that anyone with a soldering iron could do this type of repair at home. The tutorial showed the complete steps for how to do the repair, with photographic documentation of every step. Unfortunately, all of my posts got deleted from the other site when a half-brained idiot decided to ban me and purge all of the evidence that I had ever existed there. As a result, the entire tutorial got erased. Gone forever. That's too bad, as the tutorial included comparisons of the different caps that are available for the job, and included guidance about which caps were good for the job and which caps were not so good. At one point in that thread, someone joined-in who had fabricated a replacement board that he planned on selling. It sounds similar to the one you're describing. In the thread we had discussed what types of ratings were desired for the caps for this application, and the caps that were being offered in that kit at that time were not up to par. I don't know if that' s the same kit that you're referring to or something different, and now that the information has been purged from the other site, there's no way to know.

Regarding your amp, the good news is that you've got the low/mid supply rails working again. You don't ever have to worry about those caps again unless their should fail, and if they should fail, you've got a repair path in place. The bad news is that your amp has got a whole lot of other caps in there that are pretty darned old, and are likely to be out of spec. The amp would benefit from having them replaced. While most people focus on the PSU rail caps, there are other caps that are prone to fail in subtle ways, and those caps are going to need to be replaced as well. What most people don't think about is that with old amps, the aged caps in the protection circuit are prone to fail, and when the protection circuit fails you're really in trouble. That's when amps blow up.

Being the guy who started the whole Carver-recapping craze, I agree with the recommendation that it would be best to recap the entire amp when you have a chance. Until then, congrats on getting your amp working again, and enjoy the music!
Carver Preamps: C-1, C-2, BillD's JVD-modded C-4000, C-9
Carver Amplifiers: BillD's C-500, M-1.5t (4) PM-1.5 (4) M-500t (2)
Repair/Restoration/Upgrade expert for all of these components.

indyaudio
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Re: Carver M1.5t Repair Testimonial - Circuits and Concepts

Post by indyaudio » Sat Feb 22, 2014 6:15 pm

bob p wrote:I'm glad to hear that you've got your amp up and running, and I'm sorry to hear that you had problems along the way that forced you to reach out to a repair facility. The type of cap job that you're talking about isn't at all hard. It's something that anyone with decent soldering skills should be able to do on his own if they have all the right information.

Once upon a time I had written a complete tutorial about re-capping the low/mid rail caps on the 1.5 type amps, so that anyone with a soldering iron could do this type of repair at home. The tutorial showed the complete steps for how to do the repair, with photographic documentation of every step. Unfortunately, all of my posts got deleted from the other site when a half-brained idiot decided to ban me and purge all of the evidence that I had ever existed there. As a result, the entire tutorial got erased. Gone forever. That's too bad, as the tutorial included comparisons of the different caps that are available for the job, and included guidance about which caps were good for the job and which caps were not so good. At one point in that thread, someone joined-in who had fabricated a replacement board that he planned on selling. It sounds similar to the one you're describing. In the thread we had discussed what types of ratings were desired for the caps for this application, and the caps that were being offered in that kit at that time were not up to par. I don't know if that' s the same kit that you're referring to or something different, and now that the information has been purged from the other site, there's no way to know.

Regarding your amp, the good news is that you've got the low/mid supply rails working again. You don't ever have to worry about those caps again unless their should fail, and if they should fail, you've got a repair path in place. The bad news is that your amp has got a whole lot of other caps in there that are pretty darned old, and are likely to be out of spec. The amp would benefit from having them replaced. While most people focus on the PSU rail caps, there are other caps that are prone to fail in subtle ways, and those caps are going to need to be replaced as well. What most people don't think about is that with old amps, the aged caps in the protection circuit are prone to fail, and when the protection circuit fails you're really in trouble. That's when amps blow up.

Being the guy who started the whole Carver-recapping craze, I agree with the recommendation that it would be best to recap the entire amp when you have a chance. Until then, congrats on getting your amp working again, and enjoy the music!
I guess I don't have decent soldering skills. And the rest of the amp had been gone through recently by Rita's. It's good as new, figuratively and literally.
Main Room System(s):
Speakers - Polk SRS 1.2TL; Carver ALiii; KEF 101, 104/2; Pioneer HPM150; JBL S7R Sovereign, L112, 4312, 43111
McIntosh - C28, C26, C24 preamps; MC30 monoblocks, MC2205, MC2120 amps
Carver - M4.0t amp; CT17 preamp; C9 Holography; Digital Time Lens; SDA360 CD
Sunfire 300~2 (2) & Dynaco ST-70 tube (2) amps
Jolida tube & Linn Karik CD; Rega P2 & Marantz 6300 Turntables
Arcam rDAC

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