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Old 16th July 2009, 11:10 PM   #1
figge77 is offline figge77  Sweden
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Join Date: Apr 2009
Default Luxman L-510 problems

hello!

long story in short version:
"found" this amp and hooked it up, and speaker relay not cklicking.
open it up and had a look, first the filter caps in psu had leaked. i put in new ones. no click. recaped the entire psu and relay circuit. BINGO! click!. but when hooked up only sound in one ch.
found out the relay was burnt on one ch. changed it + recaped the power amp boards. and BINGO! i got sound! listned about an hour on my test speakers. then moved on to mainspeakers in workshop, my newly refurbished L-26. and after another hour the damn thing went into DC, taking out one woofer.

opened it up and the relay was burnt out on the same ch...but the amp works if i hook the speakers directly at the amp boards.
so if i put in a new relay it would work for another 2 hours.

must be that it gets hotter than hell and puts dc on one channel then cools off and works again.only taking the relay and speaker with it

this thing faces some serious heat inside. no wonder the original caps had trown in the towel.

anybody has any experience with some similar situation?

its a pretty nice amp., BUT its to crowded inside. more is less!
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Old 17th July 2009, 02:05 AM   #2
Fanuc is offline Fanuc  United Kingdom
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Default Re: Luxman L-510 problems

Quote:
Originally posted by figge77
hello!

long story in short version:
"found" this amp and hooked it up, and speaker relay not cklicking.
open it up and had a look, first the filter caps in psu had leaked. i put in new ones. no click. recaped the entire psu and relay circuit. BINGO! click!. but when hooked up only sound in one ch.
found out the relay was burnt on one ch. changed it + recaped the power amp boards. and BINGO! i got sound! listned about an hour on my test speakers. then moved on to mainspeakers in workshop, my newly refurbished L-26. and after another hour the damn thing went into DC, taking out one woofer.

opened it up and the relay was burnt out on the same ch...but the amp works if i hook the speakers directly at the amp boards.
so if i put in a new relay it would work for another 2 hours.

must be that it gets hotter than hell and puts dc on one channel then cools off and works again.only taking the relay and speaker with it

this thing faces some serious heat inside. no wonder the original caps had trown in the towel.

anybody has any experience with some similar situation?

its a pretty nice amp., BUT its to crowded inside. more is less!
Symptoms of common amp problems. Faulty output relays and reservior caps. (leakage currents from these could cause problems even if DC voltage measures OK).

These are the first things I would change (smoothers and relays). Sorry to hear you lost a woofer by the sounds of it. I would change all capacitors in the amps. (electro's) at least and re adjust the offset etc. Full DC is the most difficult condition for the amp to take. Did any fuses blow ? Some amps use really cheap trimmers. They tend to go open circuit and can allow full quiescent current through the output stage.

PS. Sounds like the amp may not have been use for a while.

Kevin
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Old 17th July 2009, 07:32 AM   #3
figge77 is offline figge77  Sweden
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Join Date: Apr 2009
hi!

no fuses blew. soon as it cools of its ready to play again...only with a broken relay. i have only one relay left so im not puting that in untill i have fixed the amp

well all electrolytic cap are changed all but the ones in the preamp section

i only have the scematic for the amp, no servicemanual not shure how to adjust the offset

voltages at speakeroutputs are fine when the amp works, and obviosly not so fine after 2 hours use.

i will resolder the ampboard in question and if that dont work im pretty much out of idéas

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Old 17th July 2009, 04:46 PM   #4
Fanuc is offline Fanuc  United Kingdom
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Quote:
Originally posted by figge77
hi!

no fuses blew. soon as it cools of its ready to play again...only with a broken relay. i have only one relay left so im not puting that in untill i have fixed the amp

well all electrolytic cap are changed all but the ones in the preamp section

i only have the scematic for the amp, no servicemanual not shure how to adjust the offset

voltages at speakeroutputs are fine when the amp works, and obviosly not so fine after 2 hours use.

i will resolder the ampboard in question and if that dont work im pretty much out of idéas

Hi,

Could you post the schematic ? or do you have a link to it?. I wonder if it's oscillating. (does the amp output stage heat up rapidly ? ). Change the trimmers/pots. If you can show the schematic I will give you some ideas to try.

Regards

Kevin
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Old 17th July 2009, 05:27 PM   #5
figge77 is offline figge77  Sweden
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hi!

all i have is schematic for L-530 and as i understand it is pretty similar schematic to the L-510. or so i heard over the internet for what thats worth. and the actual L-510 shematic is nowhere to be found.

anyway i´ll post it and hope it makes sense.
http://www.eserviceinfo.com/download...MAN_L-530.html

today i resoldered the bad channel. i also resoldered the preamp and protection board. also recaped the preamp.

didnt have time to test it. will try tonite. seems it have no problems when the lid is of. when the L26 blew up i had the lid on . there are very small vents on the lid.
and as i mentioned it gets hot as hell inside. after 30min i cant touch the zinks
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Old 23rd July 2009, 02:56 PM   #6
figge77 is offline figge77  Sweden
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any clues?

it still shuts down after some time in use and taking out the relay.

i have changed every lytic cap in the thing and have resoldered every joint on both amp boards. preamp and protection board.
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Old 23rd July 2009, 04:06 PM   #7
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Hi,

I have full L-510/530 service manual for you ready to be sent...mail me.
__________________
Non é mai abbastanza...
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Old 25th July 2009, 12:12 PM   #8
figge77 is offline figge77  Sweden
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well i adjusted every thing acording to the manual. and after that the amp was a bit cooler.
but still after a while it comes a loud sound in the "bad" channel and the relay kicks in. only now the relay doesn burn up. i just wait a minute and start the amp again and it works for a while again.
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Old 25th July 2009, 10:32 PM   #9
mjf is offline mjf  Austria
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hello.
have you tried to compare the voltage drops across the parts of the two channels.............
perhaps there is a bad transistor/diode
or an elco is built in wrong(reverted).........
greetings...........
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Old 7th May 2010, 09:55 AM   #10
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Hello !
Last March, I was proud to be the "winner" of a Lux L-510 auction. I received it at home, installed it, feeling happy with my new machine. But... after let's say 4 hours, it happened a frightening crackle sound through my speaker, and simultaneously speaker relay cklicking to protect . Orange led blinking to indicate DC / thermal protection at front.
Unfortunately the story continuation is the same as for figge77. Look:

- another day I tried again the amp. After two hours,, the same crackle loud sound, but this time, the relay didn't work...
DC voltage directly on my speaker, loud sound lke a 120 dB siren, smell of burnt coming out of my Cabasse Clipper II .
the switch for "Speaker A" stayed engaged during the incident. As I was trying to stop this massacre, it was not possible to switch off the speakers by the button !
I lost a woofer on left channel .

--> Actually, the relay coil has worked, but I found one contact was burnt inside, like a huge current has melted and soldered this contact !! That's how the DC current gone to the speaker. Moreover, I found also into switch for "Speaker A" that the contact blade for left channel was even burnt, melted.

What I have done until now:

- checked fuses: all OK
- checked for possible burnt component: none. No cap exploded, no resistor burnt, etc.
Decided to replace this:
- Replaced main PSU big Caps.
- Replaced all power transistors ( 4x 2SA1075; 4x 2SC2525)
- replaced relay
- i adjusted every thing acording to the manual ( bias current to 150mA after one minute)

Then, tried the amp again. but still after a while it comes a loud sound in the "bad" channel and the relay kicks in.

I have also checked the temperature compensation for the bias made by the component in between the power transistors. This is the unfoundable STV-2H double diode.
This seems to work properly. When i heat it up, i see the bias current decrease.

What I don't understand is why I see the bias current drifting ? ( See the pictures)
first picture with DVM is after one minute ( 150 mA) . Second picture, both channnels, is after 5 or 6 minutes (DVM reads ~185 mA).
And it continues to increase... I wonder if this can lead to the problem. Is it normal ?
Attached Images
File Type: jpg Lux L-510 tblshooting 001_small.jpg (157.8 KB, 167 views)
File Type: jpg Lux L-510 tblshooting 002_small.jpg (89.1 KB, 147 views)
File Type: jpg Lux L-510 tblshooting 003_small.jpg (112.5 KB, 145 views)
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