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Technics SL-Q3 buzz humm oh no not again....

Posted: 23 Sep 2019 13:15
by neelde
Hi Everyone,

Just recently I noticed/heard some buzz coming through the speakers when using my SL-Q3.... I used an audio frequency analyser and saw that it was a 50HZ buzz. So I thought this is just an easy fix replacing the first capacitor. But that did not improve anything :? So I decided to use a separate power supply. There is now less buzz, but I can still hear it with the volume turned up. I then decided to replace the old RCA cable. This didn't change anything still a 50Hz buzz... :cry:

I use my SL-Q3 with a Denon AVR 3311. Without the turntable connected it is dead quiet. So must be the SL-Q3...

Now what could be the next step? cause I'm out of ideas...

Re: Technics SL-Q3 buzz humm oh no not again....

Posted: 23 Sep 2019 13:45
by chgc
Are there any other power adapters near the turntable that could be causing the hum?

Re: Technics SL-Q3 buzz humm oh no not again....

Posted: 23 Sep 2019 13:46
by Tom_Technics
If the buzz is not mechanical noise coming from the unit directly, replace the ground wire.
I highly advise replacing all electrolytic capacitors within this machine even if they seem ok. They are far past their life expectancy and the SL-Q3 contains a few fragile components. An out of spec capacitor could easily lead to damage of the AN6675 or AN6680 IC's.
For the record, I have re-capped a few SL-Q3's and the story is always the same. The caps always have high ESR and I've even seen some leaking blue goo down the leads, not to mention the smell of electrolyte that jumps out as each cap is removed.

Re: Technics SL-Q3 buzz humm oh no not again....

Posted: 23 Sep 2019 14:27
by neelde
chgc wrote:
23 Sep 2019 13:45
Are there any other power adapters near the turntable that could be causing the hum?
No, I removed those. But thanks for the suggestion.
Tom_Technics wrote:
23 Sep 2019 13:46
If the buzz is not mechanical noise coming from the unit directly, replace the ground wire.
I highly advise replacing all electrolytic capacitors within this machine even if they seem ok. They are far past their life expectancy and the SL-Q3 contains a few fragile components. An out of spec capacitor could easily lead to damage of the AN6675 or AN6680 IC's.
For the record, I have re-capped a few SL-Q3's and the story is always the same. The caps always have high ESR and I've even seen some leaking blue goo down the leads, not to mention the smell of electrolyte that jumps out as each cap is removed.
Ground wire, do you mean the one from the back because I changed it together with the RCA wires.

And yes you're right, I could have thought of that... I did just that for a SP 25 like a week a go....

because of the 50hz I thought only about the first capacitor.

I'll try a recap then. Although none of the capacitors are original, they aren't young either....

cheers!

Re: Technics SL-Q3 buzz humm oh no not again....

Posted: 23 Sep 2019 16:00
by Tom_Technics
Ground wire, do you mean the one from the back because I changed it together with the RCA wires.

And yes you're right, I could have thought of that... I did just that for a SP 25 like a week a go....

because of the 50hz I thought only about the first capacitor.

I'll try a recap then. Although none of the capacitors are original, they aren't young either....

cheers!
The ground wire is the thin wire with the spade (fork) connector on the end.
If the caps aren't original, they may be of poor quality or incorrect spec. Saying that, it's probably been done by somebody who knew what they were doing as the circuit board of the Q3 is very sensitive and very easy to damage.
The symptoms you describe remind me of my SL-1610. I turned it on one day and it was spinning really slow and making a buzzing sound. I replaced all the caps and it worked fine after that.
Also, check the power cable and plug. It's also possible that there could be an issue with the tonearm wiring.