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Denon DRA 345R stereo receiver overheated

 
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Kreuzade
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PostPosted: Wed Jan 27, 2010 9:35 pm    Post subject: Denon DRA 345R stereo receiver overheated Reply with quote

I left my stereo on too loud for too long. It shut off by itself and when i got to it, it smelled like it normally did when its hot but a lot worse this time. Needless to say, it wouldn't power back on. The fuse is fine. I think its the power trans because its the only component that smells like what the whole room smelled like when it overheated... haha.

Does anyone have any advice or some steps to deduce what is wrong? Any help would be greatly appreciated.

Thank you
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train123



Joined: 26 Jan 2010
Posts: 88
Location: Canada

PostPosted: Fri Jan 29, 2010 9:49 pm    Post subject: Reply with quote

When you said the power trans overheated, I am assuming you meant power transformer and not power transistors.

Power transformers have a thermal fuse in the primary side (the ones connected to your power cord) which is designed to open if it gets too hot. To check, ensure the unit is unplugged and ohm out the primary side of the transformer, it should read a very low number. With the thermal fuse gone, your reading will show an open circuit.
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Kreuzade



Joined: 30 Jan 2010
Posts: 2

PostPosted: Sat Jan 30, 2010 1:13 am    Post subject: Reply with quote

Thank you for replying,

I am not too sure what you mean by 'ohm out', is that like measuring the resistance? I understand that I will get very large readings if the fuse is blown and very small readings if it is in tact. What i am not sure of is where to measure the resistance.

I see the two leads from the power cord. One goes into the board and is soldered to a white wire which goes to the power transformer. Further down the board there is a small fuse(which looks in tact) and right next to this fuse is a yellow wire which then goes to the power transformer. Are you saying there is another fuse inside the power transformer? If so how do i measure the resistance of it?

I tried posting a photo but for some reason i cant turn html on. so heres a link.

http://picasaweb.google.com/sjkreuze/UntitledAlbum?feat=directlink

Thanks again and any further help is greatly appreciated.




(To post a picture the address MUST end with image tag such as JPG or PNG
Vtech
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Kreuzade



Joined: 30 Jan 2010
Posts: 2

PostPosted: Sat Jan 30, 2010 6:28 pm    Post subject: Reply with quote

I just ohm'd out the power transformer and it is definitely an open circuit. If there is a fuse inside it, i cant find it. Is there a way to fix this power transformer?

(Thank you Vtech for the help with the photo)
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train123



Joined: 26 Jan 2010
Posts: 88
Location: Canada

PostPosted: Wed Feb 03, 2010 9:57 pm    Post subject: Reply with quote

The thermal fuse is in series with the windings and is under the wrappings of the transformer. If you happen to find it, do not solder the new one on since you'll likely blow the new one with the heat of the soldering iron. Crimping will work better in that situation.
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