Sony receiver "protect" mode?

Slickone

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Dec 31, 1999
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I have a Sony STR-D665 receiver, that states "protect" on the display about 2 seconds after turning it on, and it won't do anything. Does anyone know how to fix this? It does it regardless of anything connected to it or not.
 

bruceb

Diamond Member
Aug 20, 2004
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That is usually caused by a short in one of the speakers. Try disconnecting them one by one to see when (if) it does finally power up. Keep the volume Down. When it does, that one has the problem.
 

Fallen Kell

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Oct 9, 1999
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That or an internal fuse/circuit breaker has switched. You may also need to do a full factory reset, which is typically accomplished by pressing and holding the power button for 5 seconds and a screen will appear with something like "Press Enter to Clear All", hit "enter" on the remote and it will then flush to factory settings. Just make sure you have written down all your configuration data like speaker distance settings, EQ settings, SPL level matching settings, etc., etc., before you do this since all of that will be removed.
 

Slickone

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Dec 31, 1999
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That is usually caused by a short in one of the speakers. Try disconnecting them one by one to see when (if) it does finally power up. Keep the volume Down. When it does, that one has the problem.
As I said, it does it without anything connected (incl. speakers).

That or an internal fuse/circuit breaker has switched. You may also need to do a full factory reset, which is typically accomplished by pressing and holding the power button for 5 seconds and a screen will appear with something like "Press Enter to Clear All", hit "enter" on the remote and it will then flush to factory settings. Just make sure you have written down all your configuration data like speaker distance settings, EQ settings, SPL level matching settings, etc., etc., before you do this since all of that will be removed.
That doesn't seem to work on this model. It's an older receiver that doesn't have an 'enter'. This shows pictures of it.
 

PM650

Senior member
Jul 7, 2009
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It's probably detecting DC on the output of one of the channels. If it was being overdriven before this happened, it could be a shorted output transistor. Otherwise, hard to say without opening it up.
 

Slickone

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Dec 31, 1999
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It is opened. :) Not that I really know how to troubleshoot circuits. But I didn't see anything burned. There is a glass tube fuse by the transformer that looks good. I looked for cold solder joints, but I'm no pro, so if there are any, I could easily miss them.
Probably already assumed, but when it does go into protect mode, I can hear the transformer click off. The same noise it makes when you turn it on.
 

Number1

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Feb 24, 2006
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COuld be a shorted output transistor. If you can identify them try measuring them with a ohm meter. If there is a problem youll see a dead short between the leads.

You might also want to put a ohm meter between the speaker output terminal and see if there is a difference between some of them. Just a shot in the dark but you never know and make sure you unplug the unit before you make your measurements.
 

Slickone

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Dec 31, 1999
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^
I get this when I try to download it:
"Sorry. Model description. SONY STR-D665 is temporary unavailable."
 

bruceb

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Aug 20, 2004
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I was just able to redownload it .... you need to enter the validation code. If you want PM me your Email and I can send you the file.
 

mikeford

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Jan 27, 2001
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You can download the service manual from here (it has the schematics and parts list)
You need to enter a code so the site knows it is a human asking for it. Also the .pdf comes up in an odd view, but Esc in Acrobat will put it back to a normal view in Adobe reader.

http://www.givemefile.net/smanuals/radios/sony/file/30453.html

Interesting, site still is up, but I see on cost of about 4 Euros to download (a different manual). Since I did find a manual for something I own, but that isn't broken, I will keep it n mind, but skip for now.

Checking some other items I found a link to another site which had many real manual to freely download. These are real deal, service manuals, but no idea how long the site will remain active so I grabbed manuals for all the items I own.

sportsbil dot com slash sony slash STR slash STR-D