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Post by tjmotter on May 6, 2019 10:01:47 GMT -5
Yes, I would expect both channels (SW1 and SW2) to measure very similarly.
Can you check C4913 and C4914? These two capacitors store the charge for the +/- 12V lines. They are only rated for 16V so they could have been damaged when the opamp blew. They shouldn't affect the output side so you should definitely work to track down why the R4607/R4608 numbers are so different. There are a lot of parts in that circuit so it will be hard to estimate the resistance you should see but they should definitely be close to each other. These little suckers are in parallel with the capacitors as well as the transistors. I have a hard time believing that C4609 or C4607 would blow but they should be checked. I would pull them out of the circuit and see if either is shorted.
Most Onkyo's use a similar circuit here so I will try to carve some time out to take one of mine apart to give you some readings of what they should be. This will help narrow down which component is bad.
HTH
Todd
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Post by tibimakai on May 6, 2019 15:15:34 GMT -5
I have also noticed differences with C4125/C4126. I have removed C4125 and it shows 10nF, also C4607 shows 22uF. I will remove the pairs of these as well and see, if there is any difference with those.
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Post by tjmotter on May 6, 2019 15:42:31 GMT -5
Ok, I have had a deeper look at this circuit. First, I had a typo. I should have said C4609, NOT C4809.
Unfortunately, none of the models I have use exactly the same circuit but I did some quick calculations and came up with an expected resistance of a little over 20K so I think your SW1 is probably ok but your SW2 has a bad component in it. FWIW, the calculations I did look like this:
Looking first at SW1
You have two resistors in parallel from the signal to the ground: a 220K (R4608) and a 22K (R4638). If you calculate the parallel resistance of these two: R1*R2/(R1+R2) you get = 20K. Next you would add in the resistors that are in serial: R4648 (47 ohm), R4628 (100 ohm), R4618 (220 ohm). Everything prior to this is going to be blocked by the capacitor (C4609) so we can ignore it. Adding up all of this we get: 20K + 47 + 100 + 220 = 20.3K. The slight deviations between this number and your measurement (19.9/20.1) are minor so this calculation holds up.
Now, looking at SW2, the serial resistors are R4637 (22K) and R4607 (220K) and the serial resistors are R4647 (47) R4627 (100) and R4617 (220). It would appear that you have a device partially shorted somewhere between C4607 and the output pin for SW2. I doubt that it is a resistor because the resistors that are in serial are too small to affect the total resistance in your measurements. This leaves one of the following:
Q4607 or Q4617 - one of these two could be partially shorted to ground between the collector and the emitter
R4607/R4633 - not likely because they would typically blow open or shorted. If one blew open you would be seeing the value of the other on your meter (220K or 22K). If one blew closed you would be measuring 0 ohms.
R4617/R4627/R4647 - again, not likely because if either of these blew open you would read infinite resistance and if they blew closed it would have only a very minor effect on the parallel resistance circuit.
I would recommend looking harder for R4617 (follow the trace off of Pin 7 of the opamp until you find it) but I think your real issue is that either Q4607 or Q4617 is partially shorted. the only other possibility I can see is that if C4607 were shorted it would bring a lot more components into the calculation.
HTH
Todd
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Post by tibimakai on May 6, 2019 16:42:42 GMT -5
The problem with these transistor, that they show something only at collector emitter and nothing on the other two pins. Base to collector, or base to emitter is OL. Between collector and emitter shows, either 1.5V or 1.1V.
I don't remember which side it was, but on one side, both transistors were showing 1.5V(C & E) and on the other side it was 1.1V(C & E).
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Post by tibimakai on May 7, 2019 0:31:36 GMT -5
I have replaced those four transistors, and everything is symmetrical now.
In my opinion they were all open. The new ones, showed completely different, when I have tested them.
The sub is back. I have hooked up 5.1 channels and it's working great.
Tomorrow I will test it a bit more.
Thank you very much Todd, for your help. It is greatly appreciated.
Without your help, it would be collecting dust.
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Post by tjmotter on May 7, 2019 7:41:39 GMT -5
Congratulations! This was a tough one. As I said early in this thread, lightning does a LOT of damage to these receivers. They can always be fixed but this is one of the toughest things to repair since it affects so many different parts of the system. It took a lot of patience and a lot of work but GREAT JOB in getting this receiver working again!!
Todd
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Post by tibimakai on May 7, 2019 10:04:07 GMT -5
I have never done it, but there is a test that I could do, to make sure that everything is fine? I know that in the service mode there are some tests that can be done. It is worth dealing with that, if all the speakers work, audio/video at HDMI work, Wi-Fi, Bluetooth, also the tuner works.
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Post by tjmotter on May 7, 2019 10:43:30 GMT -5
I have run some of those tests and they can take many hours and frankly, I have never learned anything from them. In my experience, if you are getting sound out of every speaker, HDMI, Network and Bluetooth are working, the "SETUP MIC" function works and the system is behaving properly, there is no need to run all of the tests. Having said this, I will often run through the tests for the Fan's simply because I can't easily simulate that on my bench.
Note that some of those tests require you to do input specific frequencies and/or force a short. I don't have access to the media they use to generate the frequencies and I have never seen a good reason to induce a short (this is required to test the IProtect function IIRC). The code on that system is pretty smart already so if it detects an issue it will shut down. That is good enough for me.
HTH Todd |
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Post by tibimakai on May 7, 2019 12:02:23 GMT -5
On my last receiver(646) that I have sold, I gave three days warranty. No calls, no nothing. That person contacted me after almost two months, that some analog inputs do not work and if I can help with the repair money. I was like, what?!
He did not have speakers at that time, to test it out.
I wasn't aware, that the receiver had that issue.
Course I could not help him out, I'm not Costco, or Walmart. He had three days to test, so I don't consider myself a bad person by not helping him out.
I would like to protect myself, in cases like this.
I don't use analog, optical inputs, so I have no idea if they work or not.
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Post by tjmotter on May 7, 2019 13:54:48 GMT -5
My test rig includes:
1- HD TV (small one that sits on top of my CD Changer) - connected through HDMI
1- BluRay Player - connected through HDMI
1 - CD Changer - connected through Optical as well as analog (so that I can test both)
1 - Subwoofer
1 - center speaker
2 - front speakers
4 - surround speakers
I can test almost everything with this setup. I keep an old VCR around and if I suspect an issue with the analog video subsystem or if I am getting errors on the video processor I will pull it off the shelf and connect it through SVideo (on old receivers) and analog to see if the upscaling functions are working. I also keep an old DVD player around so that I can check the Component inputs the same way. I don't usually check the RCA Digital Audio ports simply because if the Optical is working, these have always worked as well. I did run into an issue once where the optical port wasn't working and found a broken connection. Stymied me for a minute because the Digital Audio RCA port worked. Easy fix though. Short length of wire between the voltage rail and the optical port and all was good again.
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Post by jorjel1 on Jan 4, 2021 8:28:24 GMT -5
Happy new year!
Sorry to resuscitate an old thread, but it’s relevant to my situation.
Are the subwoofer components all on the baasp-1797 board? Have a rz800 with both sub outs not working. Not very familiar with this kind of repair, but would like to at least check where it’s coming from.
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Post by tjmotter on Jan 4, 2021 14:39:35 GMT -5
The subwoofer circuits span across the entire system. For all audio outputs (including the subwoofer), the signal must flow through the DSP, DAC, ADC, Volume Chip and Mute circuits before it exits the rear. Issues in any of these areas can cause lack of output. These issues include:
DSP - top board - cracked solderball on the DSP chip - not likely since it is rare for only 1 to break
DAC - side board - there are a number of components here but if something were to fail it would most likely be an op-amp and those rarely fail.
ADC - side board - again, a number of components here but it is an unlikely subject since it would typically break other channels as well
Volume chip - bottom most board (underside) - when this goes bad everything stops working
Mute circuits - bottom most board. This is a possibility but I have only seen these fail under extreme circumstances like power surges
Are you sure the subwoofers have been enabled in the setup menus?
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Post by jorjel1 on Jan 4, 2021 17:00:56 GMT -5
Yes, the system is setup as 3.1 and during the speaker test I get the message from attachment and no sound coming out of the sub. Have tried even a Y cable from both outputs to the sub, same result. Strange is that I get a “pop” from the sub when I plug the cable.  |
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Post by jorjel1 on Jan 5, 2021 13:30:33 GMT -5
When I measure with a multimeter I get a small reading on outputs. On my Onkyo 515 there is nothing, but the sub works just fine.
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Post by tibimakai on Jan 5, 2021 14:04:52 GMT -5
You should open a new thread with your receiver.
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