View Full Version : Nikko STA-6060


mxlews
03-15-2007, 08:52 PM
I picked up this receiver for free. It's in great condition with everything working, except for the left channel, which stays at a low volume no matter how high I turn the volume knob. The right channel works fine. I'm pretty sure it's not dirty knobs, so what else could it be? Any specs on the receiver would also be nice, as I can't find much info.

Thanks,
Max

Urizen
03-15-2007, 09:01 PM
Have you cleaned the controls?

Free is always good...:yes:

mxlews
03-15-2007, 09:11 PM
Like I said I'm pretty sure it's not the controls. I have had receivers in the past where the problem was the controls, so I can tell when they are causing the problem. I have cleaned the volume knob only.

Filmboydoug
03-15-2007, 09:50 PM
67 WPC, made from 74 to 78.

Filmboydoug
03-15-2007, 09:52 PM
Oops. I was typing under the influence of sambuca. That should be 34 WPC.

Aldo
03-15-2007, 09:53 PM
Some of those older Nikkos had circuit breakers in the back. Reset them and see what happens, if they are there....

mxlews
03-15-2007, 10:15 PM
67 WPC, made from 74 to 78.

Wow, I wish! :tongue:


Some of those older Nikkos had circuit breakers in the back. Reset them and see what happens, if they are there....


I've tried resetting the circuit breakers quite a few times now with no luck.

Nikko75
03-15-2007, 10:36 PM
It's an interesting note that on some of the schematics for Nikko amps that in no place do they give a hint of the location of the gain circuit reostat(volume control). I'm searching to see if maybe a loose piece of metal wire could have found it's way in and crossed a circuit since you have sound all the time yet cannot adjust it on that channel.

Nikko75
03-15-2007, 11:22 PM
I'm pondering on the possibility of a faulty gain stage FET, but even if this were the case I'd assume you could still hear and attenuate the volume as the audio would bypass the FET through the negative feedback circuit. Seems like a bad volume control but I do not understand why the whole travel of the control would have no effect yet still allow a signal to the FET.

Another thing to check is if the output on the faulty channel the same as the properly working one(mono) of are they separated in stereo format as they should be. This may tell more.

Robisme
03-16-2007, 01:56 AM
Does the 6060 have pre-out main-in jacks on the rear like the 7070?
If so, does it have the separated/connected switch? Wiggle it around if it does.
Just a thought.

Rob

Nikko75
03-16-2007, 08:12 PM
If you can, post a pic of the internals so we can get a better ides of the layout. I had a similar problem with my 8080 and it was a burnt resistor which droppped in impedance.

mxlews
03-16-2007, 11:25 PM
I think it is still in stereo, not mono, but I will test this. I will check the jacks on the back and take a pic of the internals shortly.

mxlews
03-19-2007, 08:36 PM
http://public.box.net/mxlews04200

Download the bigger files so you can view them larger. If you need any more let me know.

Nikko75
03-26-2007, 09:21 PM
The STA-6060 uses the same preamp as mine and I'm curious if it may be suffering the same problem mine was. I noticed R906 is using a heavy resistor and though it looks OEM, this preamp usually uses a carbon/metal film resistor in this spot. Just for the heck of it, unplug the reciever and check the values of R905 and R906. On the picture I have the values. I know there is something else that causes the failure of these 2 resistors and I'm searching (possibility of B+ output from the main transformer). Another photo (closeup) of your actual preamp wouldn't hurt. It would be easier if I could actually have it infront of myself to evaluate.

mxlews
04-01-2007, 09:18 PM
I'll have to check that. Hopefully I can get to it this week.

mxlews
04-03-2007, 03:00 PM
Okay... R905 seems fine, but R906 is at .3 Ohms?? The receiver is still in stereo. I can adjust the volume on the left channel but it doesn't go up by very much.

LousyTourist
04-03-2007, 03:12 PM
maybe just crazy enough that it's worth a try... does it have any other knobs/buttons on it that you haven't cleaned? I have a tape/source switch on my preamp that occasionally makes just one channel fade out. Clean it and she-bang! good as new for another year or so.

bully
04-03-2007, 08:22 PM
I will also recommend a thorough cleaning of the controls to help eliminate them as a possible cause.

mxlews
04-03-2007, 10:18 PM
Well this is awfully interesting...?

So I just gave the controls a good cleaning. I plug it in to test it out again. I'm testing it with headphones so i decide to play with the headphone jack. With the jack half in, I get sound in both channels but I think it is mono. When I rotate the balance knob to the left while the jack is half in, everything goes silent. When I rotate it to the right the balance knob works as it should. What's going on here?

KingBubba
04-03-2007, 11:40 PM
The quarter inch stereo plug has a tip a ring and a sleeve. The tip and the ring are your left and right positive the sleeve is the common negative. When you only plug in part way only one of your positive contacts on the plug is being fed signal.

Nikko75
04-04-2007, 07:54 PM
Exactly. So you can turn up the volume on the left channel a bit more now than before? I can't say without actually having the unit here , but it may just be a volume control or even a FET issue. Visit a reputable repair centre to end the pain.:zoom:

mxlews
04-04-2007, 07:59 PM
No, nothing changed when I cleaned the controls. I can turn the left channel volume up a lil bit but I could do that BEFORE I cleaned the controls as well.

Nikko75
04-07-2007, 01:01 PM
My best advice is to take it in to be repaired.. and specify you will not tolerate bypassing circuits. So many repairmen go this way that it is not funny. It may be a bad connection between the output transistors and the binding post, a breaker ready to be replaced, so many things, but it can be found quickly.

mxlews
04-07-2007, 01:03 PM
How much could that end up costing me? How much is this receiver worth?

Nikko75
04-07-2007, 01:18 PM
It really depends on the labour involved. I diagnosed mine and so they repaired it for free, but I would expect $50 or a bit more. It can't be a serious fix, since there still is output. But it does vary with shop to shop. One will charge $20, another $300.

To me it's worth the time; if I found another Nikko like mine I would pay $350 happily, as I like the pronounced deep bass all the way down to <10Hz that mine offers. If your not too concerned with the distortion inherent in using bass boost circuits and similar, you can use passive high compliance subwoofers with excellent results.

Duffinator
04-07-2007, 01:33 PM
Where's the picture of the front of the receiver?

While on my usual Saturday morning bike ride today a neighbor had a pile of stuff in his driveway. My eagle eye caught a vintage receiver so I stopped and asked if he was having a garage sale. He said he was throwing everything out and if I wanted the receiver it was mine and that it worked. It's a Nikko and I think it's the 6060. It has a similar look to the Sherwood S7300 I recently gave to a friend. I just went to pick it up and he wasn't home so I'll try again later. How do these compare to the Sherwood or other vintage receivers of the early 70's?