TubeDriver wrote:
It is odd that monoblocks would fail at the same time. I wonder about a power surge that shorted a small cap across H and Neutral or maybe fried the SS rectification?
Exactly what I was thinking....
Roscoe
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| Author: | Roscoe Primrose [ August 2nd, 2013, 3:16 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
TubeDriver wrote: It is odd that monoblocks would fail at the same time. I wonder about a power surge that shorted a small cap across H and Neutral or maybe fried the SS rectification? Exactly what I was thinking.... Roscoe |
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| Author: | dberning [ August 2nd, 2013, 3:17 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
I suspect a rectifier diode has shorted, ironically in each one. I am guessing this because they blow the fuse even if the tubes are not installed if I understand you, bigthinker, correctly. Perhaps a line surge during a storm took them out? |
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| Author: | David McGown [ August 2nd, 2013, 3:22 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
TubeDriver wrote: It is odd that monoblocks would fail at the same time. I wonder about a power surge that shorted a small cap across H and Neutral or maybe fried the SS rectification? Looking at the photo, it is not clear if there is a cap between hot and neutral at the IEC, though I think I can make out a dark disc shape below the wiring. I agree that it is highly unusual for both units to fail in the same way at the same time, and an external event such as a power surge would be a logical cause. David |
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| Author: | TubeDriver [ August 2nd, 2013, 3:30 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
David McGown wrote: TubeDriver wrote: It is odd that monoblocks would fail at the same time. I wonder about a power surge that shorted a small cap across H and Neutral or maybe fried the SS rectification? Looking at the photo, it is not clear if there is a cap between hot and neutral at the IEC, though I think I can make out a dark disc shape below the wiring. I agree that it is highly unusual for both units to fail in the same way at the same time, and an external event such as a power surge would be a logical cause. David I also noticed that disc shape near the AC input wiring. Could be a small value, cheap ceramic cap? |
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| Author: | David McGown [ August 2nd, 2013, 3:35 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
TubeDriver wrote: David McGown wrote: TubeDriver wrote: It is odd that monoblocks would fail at the same time. I wonder about a power surge that shorted a small cap across H and Neutral or maybe fried the SS rectification? Looking at the photo, it is not clear if there is a cap between hot and neutral at the IEC, though I think I can make out a dark disc shape below the wiring. I agree that it is highly unusual for both units to fail in the same way at the same time, and an external event such as a power surge would be a logical cause. David I also noticed that disc shape near the AC input wiring. Could be a small value, cheap ceramic cap? That is what I suspect. The only problem is that if they shorted, they should take the breaker with them when plugged in. So it kind of rules that out as a possibility, since the fuse blows when turned on. David |
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| Author: | Roscoe Primrose [ August 2nd, 2013, 3:38 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
David McGown wrote: That is what I suspect. The only problem is that if they shorted, they should take the breaker with them when plugged in. So it kind of rules that out as a possibility, since the fuse blows when turned on. David Unless, and it's hard to tell from the picture, it's got one of those IEC receptacles with the fuse-holder built-in....  Need more  Roscoe |
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| Author: | Jim G [ August 2nd, 2013, 3:57 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
Hate to stick my nose into these things, but..... Safe to assume both are correctly connected to a speaker load without any shorts in the wiring? Jim |
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| Author: | randy warren [ August 2nd, 2013, 5:24 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
is it safe to assume that the poster does not have much electronics experience? If so, someone more knowledgeable may need to look at these... |
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| Author: | Roscoe Primrose [ August 2nd, 2013, 5:42 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
randy warren wrote: is it safe to assume that the poster does not have much electronics experience? If so, someone more knowledgeable may need to look at these... Probably. Patrick - I should be available pretty much any time Sat, and Sun after about 1PM if you want to make the trek all the way out here... Roscoe |
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| Author: | bigthinker [ August 2nd, 2013, 6:31 pm ] |
| Post subject: | Re: Antique Sound Labs Monoblocks stopped working |
I appreciate all the response to this post. I do not have a lot of experience but I do own an Ohm meter, so I can respond to some of your recommendations. I was thinking it was the mains transformer. If someone knows of a reputable place to get them repaired or knows for certain how to repair this, please let me know. Again, thanks for all the positive suggestions and thoughts on this problem. |
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