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YAMAHA DSP-A970 Wont Stay Powered On.

 
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kevinflath



Joined: 29 Nov 2012
Posts: 2

PostPosted: Thu Nov 29, 2012 9:19 pm    Post subject: YAMAHA DSP-A970 Wont Stay Powered On. Reply with quote

I have a DSP-A970 and its shuts off after about 3 seconds when I try to power it on.
I havent been able to find any kind of trouble shooting guide on this thing and I was hoping to get some input as to what could be the problem. I am an RF technician and quite familiar with circuit repair. Any advice would be GREATLY appreciated!
Thanks

BTW, I have looked for the Service Manual and cant find it anywhere.
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Thu Nov 29, 2012 11:23 pm    Post subject: Reply with quote

Kevin,
There is a diagnostic mode that can help out. You may have a blown channel or power supply problem. From my former days in consumer electronics, I happened to have a manual & will try to send it.
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kevinflath



Joined: 29 Nov 2012
Posts: 2

PostPosted: Thu Nov 29, 2012 11:32 pm    Post subject: Reply with quote

Thanks Vtech... I just checked the voltages out of the transformer 5v, 19v and 31v. No idea what its supposed to be LOL so the specs would be very helpful!
Thanks.
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Srinath



Joined: 26 Nov 2012
Posts: 17
Location: Charlotte NC

PostPosted: Wed Dec 05, 2012 8:54 pm    Post subject: Shorted transistor Reply with quote

This is almost textbook shorted transistor. I have had a denon that whe nI removed the output transistors off the board it would come on and stay on ... I put a new sheet of mica, some more thermal compound and it worked after that. Hope that helps.
Cool.
Srinath.
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ricortes



Joined: 15 Dec 2013
Posts: 1
Location: United States

PostPosted: Sun Dec 15, 2013 2:18 am    Post subject: Reply with quote

Zombie thread!

I found the manual. Kind of a zombie thread but if you are still around, the problem is the power supply board when it goes out this early in the start up. On mine I was only getting 3.6V on the 5V supply. I replaced the 7805 type regulator and it started up and stayed on.
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