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Post by freddypipsqueek on Aug 10, 2013 13:56:15 GMT
Guys. I would appreciate a bit of advice and a few comments. Even if you think I’m being a bit silly. My Chiarra/Andante wasn’t working last night; in fact it was given out very low valume. A quick look inside the amp showed the 15v LED wasn’t on so I opened up the Andante power supply and finding black marks around the 7815 (7815CSP) voltage regulation measured and fount no output voltage (the input voltage measured at 24v). I assume the 7815 has failed. I am happy to go to Maplin and simply pick up a replacement. I was wondering however if it was worthwhile fitting one of the fancy regulators – say this – www.hificollective.co.uk/components/nclassd_reg.html. I need something pretty simple as I am pretty simple. Cheers, Adrian
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Post by Deleted on Aug 10, 2013 15:06:53 GMT
Hi Adrian, I think I'd be rather concerned as to why the 7815 cooked itself in the first place. There may be a problem upstream causing the fried reg. I found this reference to a blown PSU by someone we all know May be worth a read, for eample the part about... Does yours the same as this pic?
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Post by freddypipsqueek on Aug 10, 2013 15:38:27 GMT
Yes that is the same as my board however mine is the original box and thus has the edge connector.
I have looked through the wires and joints for a short but can't find one.
Given your comments however it may be better not to waste £'s on anything fancy and refit a 7815 and see what happens.
Cheers,
Adrian.
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Post by Deleted on Aug 10, 2013 22:04:15 GMT
Hi Adrian, I think I'd be rather concerned as to why the 7815 cooked itself in the first place. There may be a problem upstream causing the fried reg. I found this reference to a blown PSU by someone we all know May be worth a read, for eample the part about... Does yours the same as this pic? You need to remove the 7815 and check with a DMM for any very low ohms readings on the output side of the voltage regulator. It is possible, but not likely, that it was due to long term overheating. Alex
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Post by freddypipsqueek on Aug 11, 2013 12:07:43 GMT
Alex.
I get a reading of circa 64ohms.
The 7815 was not fitted with a heatskin. I assume one was not supplied with the kit at that time (1995).
I have ordered a replaced with a heatskin and will see what happens.
I assume getting something better is unlikely to make much of a difference ?.
Cheers,
Adrian.
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Post by Deleted on Aug 11, 2013 16:10:02 GMT
The 7815 was not fitted with a heatskin. Adrian. Aha! A better chance that the reg just died of over heating then Make sure you pop a heat sink on the other reg too, before it goes the same way.
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Post by Deleted on Aug 11, 2013 21:23:40 GMT
Alex. I get a reading of circa 64ohms. The 7815 was not fitted with a heatskin. I assume one was not supplied with the kit at that time (1995). I have ordered a replaced with a heatskin and will see what happens. I assume getting something better is unlikely to make much of a difference ?. Cheers, Adrian. Hi Adrian I would just use a standard 7815 with a small heatsink fitted, and cross my fingers that there has been no further damage. Regards Alex
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Post by freddypipsqueek on Aug 11, 2013 22:27:41 GMT
I have ordered the bits. I am away for a few days so will update when I get back and I know if it has worked !!.
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Post by freddypipsqueek on Aug 17, 2013 13:49:43 GMT
Fitted a new 7815 with a heat skin and the Chiarra is back to life.
I will leave it off and swap over the 7915 (with a heat skin) to ensure this does not fail before I power it up in full.
I also propose replacing the caps as I am assuming the originals are 17/18 years old.
Any other ideas for improvement greater appreciated.
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