Marantz amp problems

Borden

Borden

Borden

Soldato
Joined
14 Jul 2005
Posts
3,810
Location
Surrey
Hi guys,

Recently my Marantz 6010KI has been randomly cutting out completely. When it cuts out you can hear a clicking noise (the same as the one you hear when you put it on mute) and sometimes it won't switch back on for hours whereas other times it will switch back on straight away. I've had a read around and it seems to be a problem with some kind of relays in the unit having dirty contacts. I'm no electronic expert though and don't know what I'd be looking for if I were to try and clean it myself.

Also, today I noticed that the right channel is buzzing constantly. The buzz doesn't change volume as you turn up the speakers and is present whether there is an input connected to the amp or not. Someone had a similar issue here and I've tried all the suggestions on that page with no luck. What's worrying though is that he says that the amp will 'go DC at some time and blow the speakers'. I don't know what he means by 'going DC' but I certainly don't want to risk my speakers.

Is my amp conking out or does it sound repairable? Bear in mind that I'm a student without a car and so the only place I can take the amp to get repaired is where I am at university (Loughborough). As far as I know there's only a small AV repair place here and I'm not sure if they can service Marantz products.

Cheers!
 
The click is probably a protection relay, so when the amp does give out DC, the relay switches in order to protect your speakers. :)

As for fixing it, I'd be tempted to open her up and look for burn marks... Get some pics if you can, 1 pic is worth 1000 words as they say... ;)
 
Thanks for the reply. I've ended up buying a replacement Rotel from the bay. I'm still interested in getting this fixed though if I can.

I opened it up and had a look but couldn't see any burn marks. Got some pictures of the internals.

Overall view: http://i193.photobucket.com/albums/z305/markwhiten/P1000599.jpg
Middle section: http://i193.photobucket.com/albums/z305/markwhiten/P1000600.jpg
Front section, the clicking is coming from behind this green PCB, will see if I can get it off: http://i193.photobucket.com/albums/z305/markwhiten/P1000602.jpg

What will the relay look like?

EDIT: Just got the front PCB off and there's nothing on there apart from an IC and some caps/resistors so the relay isn't there.
 
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Hi, looking at the pics I think I can see a relay just above those 4 large caps in the first pic.

It should look like a small plastic box, and it looks like it's grey in this case though they can vary in colour.

If you want to fix it, a multimeter will come in handy.

I'd start by making some RCA cables which short the center pin to the outside barrel, this should allow you to test for DC offset at the speaker outputs. :)
 
My guess from experience of these amps is dry joints on the main amp board or drys on the output transistors and/or the transistors mounted on the heatsinks between the output transistors.

I've no idea what's causing the buzz.
 
AtaRo said:
This amp is easy to fix.

Click to expand...
The correct place to measure the bias is at the emmiter resister which is the white ceramic looking block with three test points on top. Use the outer two to measure the bias and the center/ground the check for DC at the output.
 
Yes adjusting the bias via the resistor is more accurate but unless the op got a good meter or a scope and knows what to expect it would be easier for him to adjust the bias using the base emitter voltage as the ref.
 
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