Onkyo TX-NR609 Blown output

[dolivas27]

Ok looking for a little help with this one I picked up another TX-NR609 off of eBay knowing it had a bad HDMI board.

So I get the unit plug it in to test it out a bam it blows the SBR channel and I mean with a POP.

So I take the unit apart and replace the blown output Transistor and the few resistors that have blown. Put the unit back together and get ready to adjust the idling current.

I start to adjust the idling current and BAM blows the new out Transistors and now the 2SC5171 transistor also blows.

So once again I replace the parts that have blown and recheck everything again to see if I have missed anything. Everything looks goods.

Put the unit back together plug it in and I have the meter on the SBR channel as soon and I turn the unit on I see the meter start to climb so I let it run for a few seconds and then shut it down I notice that the SBR Transistor are starting to get HOT. What do you think I am missing?

Here is a list of what was replaced on the AMP Input stage.

R5356 & R5366 18 Ohm ¼ Resistors
R5476 82 Ohm Resistor
Q5266 2SC5171
Q5256 2SA1930 (Did not test bad but I had them on hand so I replaced it)

Everything else around this tested ok resistors, transistors, caps from what I can tell.

Here is what I have replaced on the AMP Section.

Q6056 2SC4468 (I replaced this with a Fairchild Semiconductor FJA4310OTU)
Q6066 2SA1695 (I replaced this with a Fairchild Semiconductor FJA4210OTU)
R6106 dual .22 Ohm Resistor (This did not test bad but after the replacement transistors popped again I also replace it as I had some on hand)

Once again everything else in this circuit testing good unless I am missing something.

Do you think the replacement transistors are causing a problem? I have used them in the past without problems.

Also question on the Idling Current Adjustment for the other Onkyo Amps I have worked on it says to fit the test jig with two 100 Ohm resistors and in the service manual for the TX-NR609 it does not say anything about the 100 Ohm resistors? Are they not needed on this model or is Onkyo just assuming that we know they are needed?

One last question do you think the defective HDMI board could be causing the problem? I would think not but at this point I am just not sure. I need to fix the defective channel before I can send it back to Onkyo to replace the HDMI board.

So any help that you can provide would be greatly appreciated.

Thanks,
Dean

[mmartell]

Re: Onkyo TX-NR609 Blown output

Did you check the smd resistors on the underside of the preamp board ?

[dolivas27]

Re: Onkyo TX-NR609 Blown output

Yes I have but I will check them again. I have checked and rechecked everything and just don't see any bad parts. I know I must be missing something simple I have repaired over 50 of these onkyo's.

At this point I think it might be a driver transistor so I am going to have to remove them from the circuit and test them.

Any other thoughts other than the resistors?

I am going to take it all apart later this evening to see what I can find.

Thanks,
Dean

[Longbow]

Re: Onkyo TX-NR609 Blown output

Did I miss the link you posted to the schematic? Is this actually a TX-NR906 by any chance?

[mmartell]

Re: Onkyo TX-NR609 Blown output

Nah this is the 609 - I think any one person would have a hard time coming across 50 906's.

He didn't post the link but here it is..

http://elektrotanya.com/?q=showresul...at2=schematics

[dolivas27]

Re: Onkyo TX-NR609 Blown output

Thanks guys I already have the Service manual and yes it's an TX-NR609 and when I was taking about repairing over 50 units it has been different models but I have repaired about 8 of this model.

Thanks

[mmartell]

Re: Onkyo TX-NR609 Blown output

The manual was for Longbow He knows his audio stuff if he comes back he can give you some suggestions.

[dolivas27]

Re: Onkyo TX-NR609 Blown output

I think I have it fixed I will update later today after I get some sleep.

[dolivas27]

Re: Onkyo TX-NR609 Blown output {FIXED}

Ok after several hours of trying to fix this I have it fixed and here is what the problem was.

The pad that connected to the base of Q6006 had broken from the trace.

After checking and rechecking everything for the 5th time I decide I was going to replace the Q6006 transistor.

Once I applied the iron with some solder wick to the base pin to remove the solder BAMN there was the problem all along the pad and trace had cracked apart. You would have never seen it without removing the solder.

So three sets of Output transistors and several hours of trouble shooting and I have it fixed ready to go back to Onkyo for the HDMI board replacement. WOOHOO

So in the end I had about $10 in parts for the repair and about $1000 in labor hours HAHAHA but it was worth it not to be beat! I knew I was missing something simple well simple now in hindsight of finding it.

Here are some pics of the pad and the repair.

[mmartell]

Re: Onkyo TX-NR609 Blown output

Excellent job. Where are you getting the output transistors so cheap ?

[dolivas27]

Re: Onkyo TX-NR609 Blown output

I usually purchase 25 at a time from here. and the defective ones go here


https://www.rocelec.com/parts/detail...255e1e&build=0

https://www.rocelec.com/parts/detail...255e1b&build=0

[tibimakai]

Re: Onkyo TX-NR609 Blown output

I had this happen to me too with a Yamaha receiver.
I had a fiery situation, when I turned it on.
Heatsink, it was on top of that transistor. When I have installed the heatsink, I have cracked that trace and did not know about it.
On Ebay there used to be somebody, who was repairing these boards for around $65. I have not checked lately if it is still there though. He is in Garden Grove CA. I have used him once. He installed a small voltage regulator board, on top of an IC and he may have done something else also, just did not notice.

[Agent24]

Re: Onkyo TX-NR609 Blown output

Interesting how things can blow when stuff is just disconnected! I was recently watching a video where a guy ruined some tubes in a tube amp before discovering the plate connection in the socket was loose and intermittently opening.