Onkyo Receiver Fried? (TX-SR806) -- please help

[TLS Guy]

Everything went well with the repair.. I am testing the repaired channel as I type... I will post the exact parts + cost this weekend and throw up some pics....
here is a shot of the amp section.... you can see I removed parts from one channel to test the damaged one..... (it was the right surround)

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Interesting pictures. The first I have seen of one of these receivers really disemboweled.

Please keep up the posts. The real issue will not be the parts, those will likely be less than $10, if the problem stops at the output stage, but the time you have invested in it. Those pictures already look like a fat bill at a service center.

By the way the pictures show why I'm really suspicious that receivers deliver any semblance of decent quality at power, or any power for that matter. Those 14 power transistors are really small and all lined up very close together. I would bet the biasing is very close to class B operation and little towards A. Other wise it would self destruct or shut down from heat.

It would be really good if you could show some pictures from you scope of sign waves at various powers, especially low powers. I would like to see if crossover distortion is visible.

Really nice thread this is now. I will follow along like a hawk.

 

[andrewcoffin]

The real issue will not be the parts, those will likely be less than $10, if the problem stops at the output stage, but the time you have invested in it. Those pictures already look like a fat bill at a service center.
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My thoughts exactly. I read the above post first on my phone, without the photos, and started to think I may have sold the receiver too quickly. Definitely felt better after seeing the parts and tools strewn around!

 

[MADMAN66]

The parts are 18.00 shipped. 8 in total were damaged. 6 transistors and 2 resistors.

the blown channel is working fine now and I have beat the living crap out of it today holding it @ -5 for 15 min steady....

total hours will be 3.5 hours... not to bad for not doing it for awhile...

As far as the amp goes I felt it looked a bit weak as well for what its rated at.
My 13 year old Sony seemed to have more punch... dunno maybe its not dialed in as I have no clue how to use it yet coming from such an old AVR.
The Sony also seemed brighter?

One thing I can say is I took it up to +10 and it freaked me out a bit still clear and sounding good.... the Sony would clip LONG before that...
heres another pic of it going together for testing... I will take more when I take it apart to restore the side channel I stole the parts from.

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[TLS Guy]

The parts are 18.00 shipped. 8 in total were damaged. 6 transistors and 2 resistors.

the blown channel is working fine now and I have beat the living crap out of it today holding it @ -5 for 15 min steady....

total hours will be 3.5 hours... not to bad for not doing it for awhile...

As far as the amp goes I felt it looked a bit weak as well for what its rated at.
My 13 year old Sony seemed to have more punch... dunno maybe its not dialed in as I have no clue how to use it yet coming from such an old AVR.
The Sony also seemed brighter?

One thing I can say is I took it up to +10 and it freaked me out a bit still clear and sounding good.... the Sony would clip LONG before that...
heres another pic of it going together for testing... I will take more when I take it apart to restore the side channel I stole the parts from.

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Good work. I really would like to see a sine wave on your scope at a range of powers.

If it is producing the power you say, it has to be far to heavily biased towards class B.

Where did you get the circuit from by the way, to find your way around?

 

[MADMAN66]

Honestly I just went from memory.. funny 20 years have gone by and they still make them the same way..... I did find the service manual but all it was really is the schematics... didn't help///
I really only needed the DVM as the pre-drive was fine....

As far as the scope goes I have no load for the unit... I primarily use the scope for digi stuff like this....NO its not a bomb... its a 3d printer...
I am interested in testing though... I'll need some time to purchase or build a load and get up to speed as I am an "audiophile newb"
I think maybe the 3310CI could be a good start as I wont be using it for a bit..(hehe the Onkyo is already in my rack as HDMI switching is my new friend....) plus its fine as a 5.1 until I receive the parts...
The 3310Ci is due on Monday so it wont be long!
oh btw.... I officially hate this thread now.....This has caused me to realize its time to upgrade my 100 year old SM120's (fronts) DO NOT LAUGH I was young and very poor when I bought them...
I will be looking for a new set in the 1k-1.2k range uh now?

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[AVRat]

Good job! Eh, Heh, welcome to the club!