G-8000 Popping Noise

Jeff Warner

Member
Hello Sansui people. Long time lurker, first time poster. Hoping to get a clue to maybe save me a trip to my local technician. I've been a Sansui devotee for more decades than I care to mention. They're all over my house and driving my Sonos system. You could say I'm a big fan. My wife says I'm a nut.

Anyway...

Just picked up my first G-801. Wanted one of these monsters for a long time and finally just bit the bullet. Owner said the volume control would need to be cleaned. Otherwise this puppy is gorgeous inside and out.

I hooked it up in my workshop, checked all the controls and turned it on. I was getting almost no sound but after a couple minutes I was getting a little bit on all for speakers. Started wiggling the volume control and I would get the occasional burst of sound. Then I remembered the connected/separated switch. Shut it off, played with the switch, turned it back on and wonderful wonderfulness! Absolutely stunning! All the controls were noise free and the tuner worked great.

After about 1/2 hour I shut it down to take it upstairs to hook up in the living room. When I turned it on, I immediately noticed a small popping sound coming from the left speaker every second or so but irregularly. When the popping was there (which was most of the time) any source would be pretty badly distorted possibly just on the left. Volume control had no affect on popping noise. Source had no affect. None of the other controls seemed to make a difference. Played some more with the connected/separated switch with no difference. Bypassed the connected/separated switch with no difference.

Took it back downstairs. Opened it up. New Nichicon caps absolutely everywhere! Pulled the front and bottom and the boards to access the controls. Cleaned all controls with Deoxit 5 and the connected/separated switch with Deoxit 100. Also cleaned every pin plug that was reasonably accessible including the blackened ones. Hours later... I reassembled it enough to test it and no difference. AARRGGHH!! I was really hoping it was the switch but I'm pretty certain it's clean enough now to have made a difference especially since it was fine initially for about a half hour. Boy did it sound great. So aggravating to have lost it.

So, I'm guessing it's a problem on the amp side. I'm not very technical and I personally feel I suck at soldering (for a very long time now). I'm just good enough to be dangerous. I'm great at mechanical, hardware and furniture stuff.

Anyway, sorry for the long post, I tend to be very detail oriented and verbose. I'm just hoping to get some kind of a clue. One more thing worth noting; at one point, in the living room, I was unplugging an accessory while it was on and popping and the plug violently popped out sort of causing me to bang the back of the unit. When this happened, there were several pops all at once. Tried hitting it a little bit to recreate and nothing happened.

Looking forward to your replies and thank you.

Jeff
 
Welcome to AK, I would check for cold or bad solders on F-2809 first. put some pictures too.... that's a great unit, kudos!
 
If you don't mind, what is the function of board F-2809 and where is it located? I'm looking at the service manual now. Thanks for the welcome and reply.
 
Okay, I answered my own question. Can it be removed from the bottom without unsoldering anything? I did get a good look at it from the bottom (top side of the board) but I believe you want me to look at the circuit side right?
 
I would separate it and run it amp only.
If still popping try to narrow it down to a channel.
That's a big set and much is going on. Better to get a better bead on the problem before tearing into it.
Unless the popping is severe. Don't use your good speakers for troubleshooting.
Popping usually is caused by a noisy transistor(s).
 
Oooo! Good idea! Wish I'd thought of that. Will do tomorrow. I'm all in favor of figuring things out as much as possible before I screw anything up. I'll try the pre-amp too! Woo-Hoo! I knew you guys would have ideas. It's ridiculous that it took me so long to actually join up. I should have been a founder! Yes, I'm that old.

Hipocrates, I'm still interested in your idea and will take a look at how easy it may or may not be to remove that board. My bigger problem with your idea is my ability to recognize a cold solder joint. All of mine always look cold!
 
Okay, what exactly have I learned or more specifically, what's next? I used my CA-2000 to run the amp on the G-801 and the popping was there. Did the opposite with a BA-2000 and it was nice and quiet. So, as I suspected, the problem is on the left amp side, so now what? Oh and Zepulon1 you questioned the severity of the popping. It is not severe at all. It's actually very quiet although annoying and doesn't get any louder no matter what I do but any source sound is severely distorted through that channel when the popping is happening. Which is basically all the time. Right now I'm testing with pairs of SP-3500 and SP-5500X.
 
Should I assume that the left side F-2806 is on the left side of the chassis when looking at it from above where I see that the tuner board is basically blocking access to it?
 
I'm also guessing that this is not something that I'm going to be able to diagnose and so I'll need to take it to my local technician.
 
Guess I should have looked at it again before I replied. I've got the left F-2806 in my hand now. One interesting thing, the cover for the metal box on that side is missing. I don't suppose these two boards are swappable?
 
Guess I should have looked at it again before I replied. I've got the left F-2806 in my hand now. One interesting thing, the cover for the metal box on that side is missing. I don't suppose these two boards are swappable?
they look identical to me ... so I don't think would be any reason not to swap.

Let's see if some expert chime in ;)
 
Cool! Seems like it would be a handy bit of detective work if they can be swapped. I'm also wondering if that missing cover was acting as a shield for something and could be a source of interference.
 
Once again answering myself. I suppose it's the same as talking to yourself. :banana: I tried swapping the two boxes to see if the shield made a difference. It didn't. Seems to me these two boards have to be identical since they're only documented once in the manual and have the same number. Still, since Hipocrates said wait for an expert, that's what I'm going to do. Okay, expert, time to chime in.
 
Once again answering myself. I suppose it's the same as talking to yourself. :banana: I tried swapping the two boxes to see if the shield made a difference. It didn't. Seems to me these two boards have to be identical since they're only documented once in the manual and have the same number. Still, since Hipocrates said wait for an expert, that's what I'm going to do. Okay, expert, time to chime in.
so.. the swap didn't make the pops move to the other channel right?
 
Okay, I did enough research to convince myself (thanks past posters of Audio Karma) that I could swap the boards. Swapped them and the popping moved to the right side! Woo Hoo! So now what again? Seems I've gotten a lot closer. I'll try to take some real close pictures of the board tomorrow and post.
 
Okay, I did enough research to convince myself (thanks past posters of Audio Karma) that I could swap the boards. Swapped them and the popping moved to the right side! Woo Hoo! So now what again? Seems I've gotten a lot closer. I'll try to take some real close pictures of the board tomorrow and post.
Nice!!!... we're going good my friend!

Now let's take some nice pictures! (front and back) of the board with problems, on your side make compare visually the boards looking for something weird.

Something happened with experts here, Xmas holidays maybe?
 
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