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Luxman L3 38VDC On Speaker Output?
Luxman L3 38VDC On Speaker Output?
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Old 22nd September 2016, 09:13 PM   #11
JMFahey is offline JMFahey  Argentina
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You must build and use a lamp bulb limiter, and plug the suspect amp there, no speakers atached, until certain itīs fully repaired.
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Old 23rd September 2016, 08:15 AM   #12
east electronics is offline east electronics  Greece
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replaced with what ? Are you serious about this ?
you asked for an advice ...
you have been given more than one
now you are on your own ...
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Old 23rd September 2016, 09:28 PM   #13
klh2000 is offline klh2000  United States
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Originally Posted by east electronics View Post
replaced with what ? Are you serious about this ?
you asked for an advice ...
you have been given more than one
now you are on your own ...

I used everyone's advice and nothing has worked. One of the output transistors was bad, so i changed them and the drivers.
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Old 23rd September 2016, 10:09 PM   #14
klh2000 is offline klh2000  United States
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Quote:
Originally Posted by JMFahey View Post
You must build and use a lamp bulb limiter, and plug the suspect amp there, no speakers atached, until certain itīs fully repaired.
Quote:
Originally Posted by east electronics View Post
replaced with what ? Are you serious about this ?
you asked for an advice ...
you have been given more than one
now you are on your own ...
Forgot to mention, what if the bulb tester is blinking ( dim-bright-dim-bright-dim... etc). it is also blinking along with the power light.
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Old 24th September 2016, 12:20 AM   #15
klh2000 is offline klh2000  United States
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Okay, I have made it further. I was an idiot and forgot to put Q404ab in, replacing these fixed the bulb tester blinking problem. The right channel is working perfectly.

The left channel still has issues:
-Vbe of Q402a is 9v
-Vbe of Q404a is only 0.32v, which seems kind of low
-Vbe of Q407a and Q408a is 0v
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Old 24th September 2016, 07:52 AM   #16
Mooly is offline Mooly  United Kingdom
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Luxman L3 38VDC On Speaker Output?
Vbe normally refers to the voltage across the base emitter junction and would normally be in the 0.7 volt region for all devices in a working amplifer. 9 volts is not an impossibility but it would only apply to a transistor under a reverse bias condition (i.e. a fault condition).

How does the polarity of the 9 volts relate to the device type (NPN or PNP) ?
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Old 24th September 2016, 08:16 AM   #17
Welcome is offline Welcome  France
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What did you use for transistors? Same part numbers as original? Then it's fake and blew up immediately. You need to use modern, equivalent (but different!) parts bought from a real non-shady source.
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Old 24th September 2016, 02:36 PM   #18
klh2000 is offline klh2000  United States
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Quote:
Originally Posted by Mooly View Post
Vbe normally refers to the voltage across the base emitter junction and would normally be in the 0.7 volt region for all devices in a working amplifer. 9 volts is not an impossibility but it would only apply to a transistor under a reverse bias condition (i.e. a fault condition).

How does the polarity of the 9 volts relate to the device type (NPN or PNP) ?
Quote:
Originally Posted by Welcome View Post
What did you use for transistors? Same part numbers as original? Then it's fake and blew up immediately. You need to use modern, equivalent (but different!) parts bought from a real non-shady source.
The 9 volts is base positive on a PNP transistor.

I have used all modern equivalent parts.
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Old 24th September 2016, 02:53 PM   #19
huibert34 is offline huibert34  Netherlands
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I had the same amp, with the same problem , and I replaced the elco,s on the amp boards and the problemwas solved
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Old 24th September 2016, 07:20 PM   #20
klh2000 is offline klh2000  United States
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Originally Posted by huibert34 View Post
I had the same amp, with the same problem , and I replaced the elco,s on the amp boards and the problemwas solved

elco,s? You mean electrolytic caps or something else?
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