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Post by tibimakai on Mar 9, 2019 20:37:52 GMT -5
After you find the bad channel, check every component at that channel, before and after repair. Best practice, is to compare the measurements with another channel, as mentioned above.
Todd, if there is a problem in the pre-amp section, the idle current still has to be adjusted, or only if there was an issue, with the final section.
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Post by tjmotter on Mar 9, 2019 20:48:55 GMT -5
After you find the bad channel, check every component at that channel, before and after repair. Best practice, is to compare the measurements with another channel, as mentioned above. Todd, if there is a problem in the pre-amp section, the idle current still has to be adjusted, or only if there was an issue, with the final section. Idle current tends to drift off of spec over time as the transistors wear so I always adjust them, even if I don't touch the AMP section. Good call!! |
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Post by kopraish on Mar 11, 2019 3:57:11 GMT -5
Two days i check everything on the pre-amp, i found something, but i don't know is it normal or no. On SL (Q5443),C (Q5442),R (Q5441) channels these transistors is diferent from other. Emiter-Collector 2SA949 SL (Q5443),C (Q5442),R (Q5441) when i measureon ''diode mode'' i have 1334-1445. On all same transistors on other channels (SBR,SR, L, SBL) i have only 1 when i measure with multimeter on diode mode. Is it normal? All resistors are perfect, all zener diode seems normal. i i check some capacitos with ESR meter, but they are fine.... Is it true, the problem is 100% on pre-amp board? 
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Post by tjmotter on Mar 11, 2019 6:35:30 GMT -5
Every channel should measure the same. They are identical circuits.
Yes, the pre-amp board is the most likely problem. Understand that even with this board out of the system, the Main AMP section is getting full power so if there was a problem there, the unit would shut off.
You should try to confirm that C5101, C5102 and C5103 are not damaged
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Post by kopraish on Mar 11, 2019 7:58:57 GMT -5
Yes, C5101, C5102 and C5103 are excellent. I have also this values (1300-1450 on diode mode) on Q5263 (SL), Q5262 (C) and Q5261 (R). At this moment how can i know which channels is bad and which are not..., i have 3 channels with same values, and 4 channels with another same values?  |
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Post by tjmotter on Mar 11, 2019 9:45:37 GMT -5
I am not sure why you could see a difference between these channels and not have something wrong but I trust that you have tested everything so we need to look elsewhere.
Looking at the schematic again, I see one other potential area for failure. Q6000, Q6001, Q6002, Q6003, Q6004, Q6005 and Q6006. These are all located on the Main board (not the pre-amp) BUT, they receive their power from the pre-amp board so one of these could be bad. These transistors are physically located between each set of Power Transistors and are hard to see. They are typically bent over so that they rest in a small cutout on the heat sink and are usually slathered in heat sink compound. You can measure them from the bottom side of the board.
Since they get their power from the pre-amp board, they wouldn't trip the Voltage protect circuit if that board was removed so it is possible that one of these is blown. I have never seen a transistor in this location fail (it is usually it's mate on the pre-amp board that fails) but it could happen.
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Post by tibimakai on Mar 11, 2019 10:32:51 GMT -5
The three main channels(LCR) are usually the same and the surrounds are a bit different(less power).
It could be one resistor at fault. It may not be a semiconductor.
On the newer Onkyos, 82 Ohm, 33 Ohm, 2.2 Ohm, 820 Ohm SMD (+ SMD transistor next to it) resistors fail the most. They are, at the connector and around the higher powered transistors.
I don't have a 609 service manual, in front of me.
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Post by kopraish on Mar 11, 2019 11:00:59 GMT -5
I am not sure why you could see a difference between these channels and not have something wrong but I trust that you have tested everything so we need to look elsewhere. Looking at the schematic again, I see one other potential area for failure. Q6000, Q6001, Q6002, Q6003, Q6004, Q6005 and Q6006. These are all located on the Main board (not the pre-amp) BUT, they receive their power from the pre-amp board so one of these could be bad. These transistors are physically located between each set of Power Transistors and are hard to see. They are typically bent over so that they rest in a small cutout on the heat sink and are usually slathered in heat sink compound. You can measure them from the bottom side of the board. Since they get their power from the pre-amp board, they wouldn't trip the Voltage protect circuit if that board was removed so it is possible that one of these is blown. I have never seen a transistor in this location fail (it is usually it's mate on the pre-amp board that fails) but it could happen. I measure Q6000, Q6001, Q6002, Q6003, Q6004, Q6005 and Q6006. They are absolutly same. But interesting. On every E-C on these transistors i have 1350-1360 on diode mode. if I follow the logic , and if we see my measure on Q6000, Q6001, Q6002, Q6003, Q6004, Q6005 and Q6006 may be the heath channels are SL (Q5443),C (Q5442),R (Q5441), beacouse i have there same values or i am wrong? I will re-check other four channel (capacitors) and will write. tibimakai Here, on TX-NR609 every channel is absolutly same like other( watts), all channels - same watts. Construction in pre-amp board is (L,R,C SL, SR, SBR, SBL) is perfect same, but i have 3 same channel (SL, C,R) and 4 (SR,L, SBR, SBL) other same channel when i measure. |
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Post by tjmotter on Mar 11, 2019 13:48:01 GMT -5
It is rare (but not impossible) to have multiple channels fail at once. Do you know the history on this unit? Specifically, did you own it before it failed or did you buy it broken?
I fixed an SR605 once that had 3 blown channels. The sad thing was that it was my own unit :-(.
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Post by kopraish on Mar 11, 2019 14:40:44 GMT -5
The history... i take this Onkyo from my brother. One morning receiver never won't to turn on. I am first person which open this receiver.
In your SR605 what you mean ''blown channels'' ....short or something else?
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Post by tjmotter on Mar 11, 2019 15:25:07 GMT -5
The history... i take this Onkyo from my brother. One morning receiver never won't to turn on. I am first person which open this receiver. In your SR605 what you mean ''blown channels'' ....short or something else? The short story is that I turned the Receiver on in 2012 and left it running continuously for 5 years. When it finally died, I opened it up to investigate and found that the Power Transistors on 3 channels had all shorted, The big 0.22ohm 5 Watt resistors for these channels were blown open, the high gain transistors (1740_S) that control the idle current were blown and the pre-amp section for each channel was damaged. In addition, about 70% of the capacitors in the Receiver had degraded significantly. This was my first Onkyo project. FWIW, this Receiver is now working perfectly again :-).
I am glad to hear that you know the history. It means that the amp was likely cared for properly. In this context, I am doubtful that the amp was abused as much as mine but it might not hurt to understand how many hours the Receiver has on it. To find this you can do the following:
1) Turn the amp on. 2) Press and hold the "DISPLAY" button 3) While holding "DISPLAY" press the "ON/STANDBY" button - the MAIN Firmware level will now be displayed 4) Release both buttons and within 3 seconds, press the "SETUP" button. - the hours of use should now be displayed.
thx Todd
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Post by kopraish on Mar 12, 2019 7:38:48 GMT -5
2888h  |
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Post by tjmotter on Mar 12, 2019 18:43:46 GMT -5
GREAT! with such low use it is not likely to have multiple blown channels. I am traveling right now but will spend some more time on the schematics when I get back
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Post by kopraish on Mar 13, 2019 1:10:13 GMT -5
I need to work only L/R, what will happen if i resold all connectors on pre-amp boadr without L/R?
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Post by mastertech on Mar 13, 2019 10:38:51 GMT -5
I really hate it when working blindly. I would be trying to identify which channel(s) have the problem. I would try doing the idle current test to see if a channel reads higher then others. I would not try to adjust, just test.
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