Hi all,
I have on my desk a Luxman r-1050 for repair. But it doesn't work.. it powers up.. the red indicator led blinks.. there is a click, so the speaker protection is working, and then the led goes out. then nothing
there are no blown fuses, I checked all the caps. there are no signs of burned parts
normally I'm over at the tube amp section and this amp looks anything but the minimal designs that I'm used to.
is there anybody who knows where is should look next?
I have on my desk a Luxman r-1050 for repair. But it doesn't work.. it powers up.. the red indicator led blinks.. there is a click, so the speaker protection is working, and then the led goes out. then nothing
there are no blown fuses, I checked all the caps. there are no signs of burned parts
normally I'm over at the tube amp section and this amp looks anything but the minimal designs that I'm used to.
is there anybody who knows where is should look next?
The amp behaves correctly, so it should be working.
Have you checked the speaker selector switch? Do you get sound from the B outputs? From the headphones?
Clean all switches and potentiometers with contact cleaner.
Try all button combinations. Everything should be disengaged (minus the speaker selector, of course). The tape monitor switch can be problematic.
Have you checked the speaker selector switch? Do you get sound from the B outputs? From the headphones?
Clean all switches and potentiometers with contact cleaner.
Try all button combinations. Everything should be disengaged (minus the speaker selector, of course). The tape monitor switch can be problematic.
ah the friend who asked me to look at it thought it was the other way around, so with that cleared up I looked at the amp again and....
while testing the amp with the builtin receiver. once I pressed the "fm muting" switch I was blown away by radio noise
I did find a component that looks busted though. see the attachment. don't really understand what happend there.
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Looks fine to me. Just some gunk on it. The big transistor is almost certain to be fine, but the smaller one could be worth replacing. But it's most likely fine as is. If it sounds right, I wouldn't bother.
D102a/b is a dual diode that is known to cause issues. So if you have problems with the power amp, consider checking those out. Replacement is 2x 1N4148 in series.
D102a/b is a dual diode that is known to cause issues. So if you have problems with the power amp, consider checking those out. Replacement is 2x 1N4148 in series.
To adjust idle current, remove the fuses indicated.
Your meter should be set to 100/200 mA or equivalent setting. mA - not mV - a lot of people make this mistake.
The amp will not come out of protection when those fuses are out. When you put your ampere meter across the fuse holders (do it with power off - and definitely with some sort of clips), it will come out of protection.
If the ampere meter fuse is blown in your multimeter, likewise - the amp will not come out of protection. Never make any sort of adjustment when the amp is in protection.
Adjust to 50 mA. Note that the variable resistor may be very sensitive. Spray it with contact cleaner or lubricant and wait for half an hour or so before you touch it because otherwise it may behave erratically (unpredictable) and even go open - this will kill the amp.
Your meter should be set to 100/200 mA or equivalent setting. mA - not mV - a lot of people make this mistake.
The amp will not come out of protection when those fuses are out. When you put your ampere meter across the fuse holders (do it with power off - and definitely with some sort of clips), it will come out of protection.
If the ampere meter fuse is blown in your multimeter, likewise - the amp will not come out of protection. Never make any sort of adjustment when the amp is in protection.
Adjust to 50 mA. Note that the variable resistor may be very sensitive. Spray it with contact cleaner or lubricant and wait for half an hour or so before you touch it because otherwise it may behave erratically (unpredictable) and even go open - this will kill the amp.
Ah thanks for reminding me to check te fuses... Also one of the alligator clips was broken.. Using a fluke 175 so with auto range not much that could go wrong. Anyway I measure 97mA on the left Chanel! Which raises the question do I need to measure the current on both channels simultaneously?
If I recall there are two fuses on each channel. You're only measuring across a single fuse, right? Also, only remove one fuse per channel. Those numbers seem doubled. Otherwise, we have problem that I cannot quite understand. Too much current there, obviously. Does the amp run hot? It's only supposed to be slightly warm - if that.
Is the battery fine in your meter? A low battery can cause all sorts of unpredictable readings.
Is the battery fine in your meter? A low battery can cause all sorts of unpredictable readings.
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yes I do measure with one fuse removed. while browsing the web for images I noticed this one looks different, it seems modded. maybe that's why the bias is higher.
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I've seen that board before. I think it's the NL company Audioscript that put that in there. They apparently liked to screw around with their products before selling them, adding in a bunch of junk for some reason. Here's some mention of that (not the same amp though) - Luxman audio products
That board is in the tuner, though, so it should have no effect on the idle current of the power amp.
Here's some mention of that (not the same amp though) - Luxman audio productsThat board is in the tuner, though, so it should have no effect on the idle current of the power amp.
checked the potmeters.. they are fine!
do the speakers have to be disconnected when setting the bias? When testing without the speakers connected I measure 48mA
then a last question, In some old tube amps i've added a primary 12v winding in series with the primary of the power transformator. this is because the voltage from the outlets are about 10v higher these days. is this mod needed for this solid-state amp or won't the extra voltage hurt the amp?
do the speakers have to be disconnected when setting the bias? When testing without the speakers connected I measure 48mA
then a last question, In some old tube amps i've added a primary 12v winding in series with the primary of the power transformator. this is because the voltage from the outlets are about 10v higher these days. is this mod needed for this solid-state amp or won't the extra voltage hurt the amp?
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and thanks for you help!- Status
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