Help with G-9000DB crackling sound!

[stevo1214]

Hi Sansui experts! I purchased this G-9000DB knowing it was stuck in protection mode and blown right channel. After a month of replacing the trim pots,many blown resistors,transistors and all of the small e-caps.I didn't recap the oval caps yet.I also did clean all the switches and potentiometers 3-4 times each.I was able to bring it back to life again. But I still have the problem with the crackling sound on the right channel. I did switch the driver boards from right to left but the crackling sound is still with the right channel. Then I disconnected the connection switch and use the G-9000DB as preamp and my AU-717 as power amp then everything is fine. Then when I use the G-9000DB as power amp and the AU-717 as preamp then I can hear the crackling sound on the right channel again. I hope Sansui experts can guide me to find this annoying issue. I'll appreciate all of your help.

 

[stevo1214]

Does anyone have any idea which board/boards should I focus on ?

 

[LBPete]

From your description, the sound is present when driving the amp section with another preamp. That pretty much says the issue is in the amp. You also said you switched the driver boards left to right and the sound stayed in the same channel. I'd be looking at those sections of the affected amp other than the driver board.

Be sure the speaker relay contacts are clean, the connected/separated switch is clean, then tap components with a wooden or plastic stick and or use freeze spray to chill components.

- Pete

 

[stevo1214]

The thing is that I don't know when the G-9000DB is used as power amp,which board/boards is involved ? so I can eliminate the other boards that is not involved and put my focus on those that are. The speakers relays and protection relay are brand new. I didn't replace the soft start relay but just deoxited it and cleaned the contacts with q-tips. I'll try to clean the connected/seperated switch again. Thanks Pete.

 

[stevo1214]

I think I'd just found the problem, I just switched the main oval caps from right to left and the crackling sound is now on the left channel. Now I wonder how hard to stuff the oval caps.

 

[kevzep]

I think I'd just found the problem, I just switched the main oval caps from right to left and the crackling sound is now on the left channel. Now I wonder how hard to stuff the oval caps.

Its not that difficult to do, I used these caps, Panasonic T-HA (105˚)10,000µf 80V.

You could search on the forum here and find a few threads about it.

Those panasonic caps are the largest ones that will fit in that cans......

Go for it, I did mine in a couple of hours, just take your time and it will ba all good.........

 

[stevo1214]

Its not that difficult to do, I used these caps, Panasonic T-HA (105˚)10,000µf 80V.

You could search on the forum here and find a few threads about it.

Those panasonic caps are the largest ones that will fit in that cans......

Go for it, I did mine in a couple of hours, just take your time and it will ba all good.........

I just removed the left 2 oval caps and yep one is corroded very bad,the flat wire is almost broke off from the connector. Those Panasonic T-HA (105˚)10,000µf 80V caps are out of stock at mouser until June, But they do have the 12000uf 80v in stock in 40mm x 63mm, But it's the T-UP series. I wonder if I can use those instead. Is there a big different between T-HA VS T-UP series?

 

[kevzep]

I just removed the left 2 oval caps and yep one is corroded very bad,the flat wire is almost broke off from the connector. Those Panasonic T-HA (105˚)10,000µf 80V caps are out of stock at mouser until June, But they do have the 12000uf 80v in stock in 40mm x 63mm, But it's the T-UP series. I wonder if I can use those instead. Is there a big different between T-HA VS T-UP series?

You probably can, as long as the dimensions are correct, the extra capacitance wont be a problem....
Just compare the specs, I think you'll be fine....

 

[stevo1214]

I wonder Why the data on the T-UP series says it's 85˚ but Mouser says max temp is 105˚? Mouser got it wrong?

 

[kevzep]

I wonder Why the data on the T-UP series says it's 85˚ but Mouser says max temp is 105˚? Mouser got it wrong?

Yes mouser probably got it wrong I'd say, I would be inclined to believe the manufacturers specs.....

You could easily use the 85˚ caps, no problem at all......

Thats what most caps are in those applications....the higher temp just gives it a bit longer life......

I'd go for it.....

 

[stevo1214]

Thanks Kevin! I'd ordered from digikey the T-HA ones,I want ones that last a bit longer. They cost a bit more than Mouser,But I can't wait until June. So what the heck!

 

[stevo1214]

Finally! I have some time to put the finishing touch on her. I also installed new speakers binding posts.I'm so proud of myself,less than a year ago,I didn't know jack about electronics and now I have recapped and restored 2X Sansui AU-717,a G-5700,a G-6000 and G-9000DB. .

I would like to thanks all Sansui experts for helping me,especially with my first AU-717 to get me going and to be brave enough to tackle the 3 receivers on my own with little help. :thmbsp:

This is a bad/corroded oval cap that causes the crackling sound.

This is what it supposed to look like.

New speakers terminal.

She's up and running beautifully.