Cannot make any sense of this problem

[pwauk12]

Just seen comment 19 which implies it is in the main amp section or protection circuit. I would replace the relay

 

[pluske]

The challenge is to find which section of the amp is causing the problem. This noise should be measureable as AC or Dc on the output of the preamp section/input ot the power amp section (Marked as 1 on the circuit). Also have you tried to measure AC or DC on the right speaker output, noting the value (high) when the amp is turned on and consistent when it has stabilized?

Do you have a scope or any test gear?

No, I dont have test gear and do not know how to read a diagram. Maybe will learn one day but do not have the space in my life for that right now.

Could the issue be arising in the power amp/preamp section if the static volume is unaffected by changing the volume/source/balance etc? I thought (naively) that his puts the issue downstream of all that business. Again, when I turn on the stereo the only thing that stops deafening, variable static is to turn off the speaker selector and then after a time it subsides to the level where I am not worried about blowing a speaker driver. I (again, naively) thought this was some sort of electric charge accumulating and then discharging somewhere very near the final output components.

 

[pluske]

Just seen comment 19 which implies it is in the main amp section or protection circuit. I would replace the relay

Reading some other L-80V threads it looks like the relay has fragile/weak fuses that often present problems. Does this sound like a bad/broken fuse could be the issue? I can do a fuse. I found the schematic for the relay but I cannot find the fuse value in the manual anywhere.

Really appreciate you taking the time to look at this.

https://www.rsp-italy.it/Electronics/Audio%20Schematics/Luxman/_contents/Luxman%20L80%20L80V%20service%20manual.pdf

 

[pluske]

based on other threads seems like it should be 5A 250V fuse?

 

[pwauk12]

Pragmatically, change the fuses (make sure they are the right values- 5A 250v), clean the fuse holder (if there is any oxidation),check and reflow the solder on the relay

however I think it is either the relay, a cap in the main amp or a noisy transistor in the main amp

you might consider finding a local tech to assist

 

[gadget73]

if its the relay, fair guess a light tap on it will make the noise louder or maybe vanish randomly. Don't beat on it but a light tap with a pencil or something wouldn't hurt.

 

[pluske]

Pragmatically, change the fuses (make sure they are the right values- 5A 250v), clean the fuse holder (if there is any oxidation),check and reflow the solder on the relay

however I think it is either the relay, a cap in the main amp or a noisy transistor in the main amp

you might consider finding a local tech to assist

thanks. Would love to find a tech. Tom B has had the amp twice already, but he has not replied to my message and I am a little worried about him now, he is not a young man. Also, much less importantly, I do not know who to turn to in NYC area if not Tom.

 

[Mr Boochie]

In the entire unit or just in the relay? The problem is in one speaker. Switching the stereo mode to reverse does not move the problem from one to the other.

Well, try the relay. Inspect the solder points with a magnifying glass. Sounds like there may be several bad points.

 

[Tom B]

thanks. Would love to find a tech. Tom B has had the amp twice already, but he has not replied to my message and I am a little worried about him now, he is not a young man. Also, much less importantly, I do not know who to turn to in NYC area if not Tom.

Not to worry. The person who "is not a young man" is still around and vertical. I have just been very busy.
The issue is not relay or fuse related if you are getting static or noise at 0 volume level. That points to an amplifier issue after the volume control, or some external interference from possibly a neighbors ham radio of other transmitting device. Turn off the speakers and use a set of headphones on initial power up to see if the noise is apparent on one channel. If it is, the issue is in the amplifier circuits. I am currently under the weather, but you can call me tomorrow or Thursday if you like. Tom

 

[pluske]

Not to worry. The person who "is not a young man" is still around and vertical. I have just been very busy.
The issue is not relay or fuse related if you are getting static or noise at 0 volume level. That points to an amplifier issue after the volume control, or some external interference from possibly a neighbors ham radio of other transmitting device. Turn off the speakers and use a set of headphones on initial power up to see if the noise is apparent on one channel. If it is, the issue is in the amplifier circuits. I am currently under the weather, but you can call me tomorrow or Thursday if you like. Tom

Tom! Good to know you're still up and about. I'll get in touch later this week.