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Luxman L-480 Overheating Help

Honcho52 said:
The L-480 does. The tech I found wants to do a full restauration.
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Yes, it does have the liquid cooling. My comment was to David who thought the 580 did but he found documents that agree with what I saw in my 580

A full restore isn't a bad thing at this age. New electrolytic caps, maybe variable resistors for setting bias and offset if equipped and new relay and proper cooling added to those transistors that get hot and the unit would be ready for another long term without issues. If the price is right, would be worth it.
 
244 is cheaper than US by 150-250 I’d guess. But it is an amp not receiver so less work overall and he may have experience with that unit and know any issues.
 
244 is reasonable for fixing the transistor issue and recap. Make sure it includes new bias trimmers and insist parts from a reputable supplier such as Mouser or Digikey. There are too many unreliable counterfeit components coming out of China that are sub-standard.
Well worth the money IMO.
 
David Weaver said:
I used a pair of KSA1220A-Y and KSC2690A-Y's. I forget which one is end of life but you can still get them from Affinity For Artifacts.

View attachment 2927469

These are beefier than the originals but they still put out a good bit of heat. Heatsinks required!

I hope you get yours up and running. Beyond the heat issue, they are wonderful sounding units!
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@David Weaver I am going to be bugging you a lot. I have a L-480 as well. It was my father's who passed away 17 years ago and I remember listening to it growing up. I have the same similar burn marks on on the board around those transistors. I had a similar problem to what you had last I fired it up but now I can't replicate it currently. I want to restore this unit and use it along side my dad's JBL L26 and Epicure 100+. Can you help me with a parts list? I would want to recap it as well. Thank you in advance
 
DJGLIVE, I'll see if I can find my Mouser/Digikey orders and post the list.
Does your unit currently go out of protection mode after about 10 seconds?
If so, does it give off an oder when it is on for a while?
 
David Weaver said:
DJGLIVE, I'll see if I can find my Mouser/Digikey orders and post the list.
Does your unit currently go out of protection mode after about 10 seconds?
If so, does it give off an oder when it is on for a while?
Click to expand...
From what I recall it took a while to go into protection mode. And there was issues with the sound quality. I am going to have to grab another speaker that isn’t in pieces to test it again. I currently don’t have any speakers here that are capable of being used to test the amp again. I did run it after cleaning it and the audio is clear through the phones jack.
 
David Weaver said:
View attachment 2345987

I have this beautiful Luxman rig that I acquired from my brother but the amp (L-480) has an issue that is apparently common to these models. I did find the following that best describes the problem from Geoffrey Kolbe (May 6, 2008) on an other forum:

"There seems to be a problem with a particular transistor pair (2SA 949 and 2SC2229) in the power amplifier section which can lead to an intermittent fault. The transistors run very hot and as they age, one of them can break down intermittently, (probably Zener breakdown as the rail voltage is quite high at 53volts), changing the quiescent DC output voltage of the amplifier. The DC voltage should be zero, and a relay disconnects the speakers if the voltage rises to +/- 1 volt or so. The red light on the front panel starts to flash, (as it does at switch on as the voltages settle) Replacing the 2SA 949 and 2SC2229 transistors with a pair of transistors that can take a heat sink would be a good idea."

Would anyone one on AK experienced the same issue and if so, what did they do to remedy it or who could I contact to get the unit repaired?

Thanks!
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What is the EQ model number. It is beautiful and I would love to add it to my amp and tuner set. I ordered the transistors you used and have all the nichicon caps to do the whole amp now.
 
David Weaver said:
DJGLIVE, I'll see if I can find my Mouser/Digikey orders and post the list.
Does your unit currently go out of protection mode after about 10 seconds?
If so, does it give off an oder when it is on for a while?
Click to expand...

Looking at replacing the main caps on my L-480 and running into issues finding a nichicon or an audio grade capacitor.

Spec is 10000uf 63v diameter: around 35mm Height: around 60mm
 

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When I needed them it was during the Covid Parts Shortage and those KEMET's were the only ones in Stock that fit.
It's good that there's more choice now.
 
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