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Post by jorjel1 on Jan 5, 2021 14:23:12 GMT -5
Hello, I am trying to debug the SW output issue I have with my RZ800. I don’t know its history, just got it like this. The subwoofer outputs are both not working and during initial setup I get the attached message. Playing a .1 source, I have a 0.1V reading on both outputs and no sound out of the sub. My other Onkyo (515) has a reading of 0 and everything works fine on both outputs. I was wondering if I should start from the top bord or if it can be likited to the baasp-1797 board. Thanks for checking  |
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Post by tjmotter on Jan 5, 2021 17:46:51 GMT -5
I thought I responded to this in a different post but after reflection, I would recommend that you check Q4617, Q4618, Q4607 and Q4608. These are the Mute transistors that control the two subwoofers. Other items in this area that could affect only the subwoofers would be Q4121 (op amp). Note that the opamp is unlikely to blow but you should check the +12/-12V supply lines for it that route through connector P9201.
These transistors are located on the bottom most board on the underside.
HTH
Todd
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Post by jorjel1 on Jan 5, 2021 23:17:47 GMT -5
Never removed so many screws to get to a board .... Will test the transistors tomorrow. I hope they are open  |
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Post by jorjel1 on Jan 6, 2021 10:44:27 GMT -5
I thought I responded to this in a different post but after reflection, I would recommend that you check Q4617, Q4618, Q4607 and Q4608. These are the Mute transistors that control the two subwoofers. Other items in this area that could affect only the subwoofers would be Q4121 (op amp). Note that the opamp is unlikely to blow but you should check the +12/-12V supply lines for it that route through connector P9201. These transistors are located on the bottom most board on the underside. HTH Todd Thank you, Todd, have tried to find the specs for these. Is the assumption from the picture correct? If yes, would the diode test be enough to determine if they are good or bad?  |
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Post by tjmotter on Jan 6, 2021 10:51:28 GMT -5
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Post by jorjel1 on Jan 6, 2021 12:45:03 GMT -5
On all of these transistors on the board with Positive to Emitter and Negative to Collector I get a reading. Can really all of them be bad? Only one is still good: Q4691
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Post by tjmotter on Jan 6, 2021 15:21:37 GMT -5
Q4691 is a PNP transistor while these should all be NPN. To answer your question, They tend to blow because of some event (like plugging/unplugging the SW while a large signal is being passed) so yes, in my experience when one goes, all 4 often blow.
These pre-biased transistors are a pain to test. The SW parts are identical to the other channels so they should measure the same as parts like Q4606, Q4616 etc.
In your case, because you currently have no SW signal at all, I would simply remove two and test the system. These transistor simply shunt the signal to ground when the "Mute" signal is applied to the collector so (for SW1) if you remove Q4618 and Q4608, you have eliminated the ability for the "Mute" signal to trigger. Don't be surprised if you start getting popping noises at startup and during transitions (which is why this is only a diag test and isn't a good "fix") but this will let you know immediately if they are the source of the problem.
I once repaired an NR616 that had been struck by lighting. It blew the Main CPU, the Volume chip and dozens of parts including 100% of the mute transistors. I did the big work first and only realized that the Mute transistors were bad because I would get a loud popping noise at startup.
HTH
Todd
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Post by tibimakai on Jan 6, 2021 18:10:25 GMT -5
Todd, do you remember my 800? I had to replace a lot of these transistors(all of them, for all the channels), I even had a bad opamp as well, had a hole in it.
jorjel1, watch out, because these boards do not like to be heated up much, they tend to pop up(bubble up).
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Post by jorjel1 on Jan 6, 2021 21:28:25 GMT -5
That is my fear with how many are on the board. Will be also hard to source parts locally as these components are not considered essential  Do you recommend an online store that ships to Canada? |
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Post by tibimakai on Jan 6, 2021 21:35:12 GMT -5
I buy my parts from Digikey. There I have purchased those transistors from, that Todd recommended. I select the basic postal service, to be cheap the shipping. Last time I had a similar issue, I think that I have replaced, at least 18 of those.
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Post by jorjel1 on Jan 6, 2021 21:53:21 GMT -5
Seems that the RN1441 is discontinued based on digikey’s site
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Post by jorjel1 on Jan 10, 2021 18:11:11 GMT -5
It seems all mute transistors are fried on the peamp board, 28 NPN and 1 PNP. This will be fun...
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Post by jorjel1 on Jan 13, 2021 15:48:30 GMT -5
Replaced the 4 mute transistors...nothing changed
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Post by tjmotter on Jan 21, 2021 16:40:46 GMT -5
Were you able to find RN1441's? If not, send me a PM with your address. I still have a couple of new parts and can spare a couple.
Also, if they weren't RN1441's, I would want to confirm that this is the issue. The easiest way to do this would be to remove the 4 transistors and test it again. If no resistors are present, you will get a popping noise during startup and will also hear a popping noise during conversions (like DTS to Dolby). If you get the popping noises, replacing the transistors with the proper ones may solve the issue.
The only other thing I can think of is that the SW solderball on the DSP has detached. Fixing this would require a reflow of the DSP chip. Not the easiest repair but do-able.
Let us know.
thx
Todd
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