artarama Posted April 6, 2012 Share Posted April 6, 2012 I just got a Luxman LV-109 integrated amp circa '85-'87 from the original owner. He said it worked great when he put it away (in the original box) 5-10 years ago. He also said he had used it very little before that. I believe all of this as the unit is perfect. I plug it in, make sure all the settings look good, speakers switched off, volume all the way down and only a tuner hooked up for input. When I powered on the lights came on for a few seconds then a fuse blew. I opened it up and there is a 10A, 125V fast blow fuse. I replace it, same result. So, any ideas? Any possibility of bringing this up with a variac to any benefit? Everything looks perfect inside, no bulging caps, burn marks nothing. This is not a tubed "brid", all solid state, lot's of transistors. Thanks! Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 6, 2012 Share Posted April 6, 2012 electronics over 10 years old that have not been used in 90 days might need to be brought up on a variac to allow the caps to reform. Quote Link to comment Share on other sites More sharing options...
djk Posted April 7, 2012 Share Posted April 7, 2012 That having been said, the amplifier in question probably needs to have its caps replaced. You have to do the variac thing before plugging it straight into the wall. For best results I recommend pre-heating the unit in an oven to 85°C (185°F) for about an hour before attempting to re-form the caps. This process allows the electrolyte to redistribute itself evenly inside the caps. Quote Link to comment Share on other sites More sharing options...
artarama Posted April 7, 2012 Author Share Posted April 7, 2012 For best results I recommend pre-heating the unit in an oven to 85°C (185°F) for about an hour before attempting to re-form the caps. This process allows the electrolyte to redistribute itself evenly inside the caps. I like that idea, makes sense. I really hate to replace anything yet, as this is as close to "new in box" for a 25 year old machine as I have seen. There are a couple of Elna caps in there that are at least an inch in diameter. Quote Link to comment Share on other sites More sharing options...
JJkizak Posted April 7, 2012 Share Posted April 7, 2012 Maybe it has to have a load? JJK Quote Link to comment Share on other sites More sharing options...
djk Posted April 7, 2012 Share Posted April 7, 2012 Maybe the electrolyte has to be redistributed so the caps don't short out when you suddenly hit them with full voltage. IF you want to really do it right, you will remove the cap from the unit and use a CCS (constant current source) of about 10mA from the maximum rated voltage for the part (pre-heat before re-forming). Obviously this is a PITA for small caps, and they are so cheap it is just best to replace them when you have them out. Expensive computer-grade caps are worth taking the time to try and save. Once the caps are shocked with full voltage after an extended period of non-use amd develop a short they will have to be scrapped. Quote Link to comment Share on other sites More sharing options...
JBryan Posted April 8, 2012 Share Posted April 8, 2012 What JJK said...You did have speakers or a dummy load hooked up to the amp, right? Quote Link to comment Share on other sites More sharing options...
artarama Posted April 8, 2012 Author Share Posted April 8, 2012 Well, yes and no, just like most things audio. I did have a pair of Cornwalls hooked up all ready to blossom, with the new power but I had all the speaker select buttons off on the amp so no power to the speakers. In "Cap land" I don't know where that leaves us. Where sould the most suspect cap be? Sounds like I missed an opportunity by not using a variac first. I still may try "baking it" and then turning it on with a new fuse. Quote Link to comment Share on other sites More sharing options...
artarama Posted April 9, 2012 Author Share Posted April 9, 2012 Well I tried to bake the amp, but it won't fit in my oven. The amp is only 18" x18" but the the oven is just not that deep. I heated up the insides with the top off and a hair drier for about ten minutes and the caps were almost hot to the touch. I hooked up a pair of 8 ohm speakers and this time turned the speaker select button on as well. I had the volume all the way down and the 30 db attenuate button on too. This time it did take a few seconds longer to blow the fuse and there was a little "errrgh" noise coming from the amp, not the speakers. Is there any chance a variac would do any good at this point? Quote Link to comment Share on other sites More sharing options...
djk Posted April 10, 2012 Share Posted April 10, 2012 No. Quote Link to comment Share on other sites More sharing options...
artarama Posted April 10, 2012 Author Share Posted April 10, 2012 No. OK, great that's what I wanted to know. I found a guy today close (30 miles) that was an authorized Luxman repair guy and has been a tech for 45 years. I'm going to have him take a look at this. I may ask the guy to let me work for free on weekends to learn this stuff. There is going to be a real gap in audio knowledge when these old guys pass. I'm an old guy too by the way, I just like to work on my own stuff, Quote Link to comment Share on other sites More sharing options...
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